UNIVERSIDADE FEDERAL DE SANTA MARIA CENTRO DE CINCIAS RURAIS

PROGRAMA DE PS-GRADUAO EM AGRONOMIA

ESCALA FENOLGICA, REA FOLIAR E DESENVOLVIMENTO DE HASTES FLORAIS DE

GLADOLO EM FUNO DA POCA DE PLANTIO

TESE DE DOUTORADO

Natalia Teixeira Schwab

Santa Maria, RS, Brasil

2014

ESCALA FENOLGICA, REA FOLIAR E

DESENVOLVIMENTO DE HASTES FLORAIS DE GLADOLO

EM FUNO DA POCA DE PLANTIO

Natalia Teixeira Schwab

Tese de Doutorado apresentada ao Programa de Ps-Graduao em Agronomia, rea de Concentrao Produo Vegetal, da Universidade Federal de Santa Maria (UFSM, RS), como

requisito parcial para obteno do grau Doutor em Agronomia

Orientador: Prof. Nereu Augusto Streck

Santa Maria, RS, Brasil

2014

2014 Todos os direitos autorais reservados a Natalia Teixeira Schwab. A reproduo de partes ou do todo deste trabalho s poder ser feita mediante a citao da fonte. E-mail: natalia_schwab@hotmail.com

Universidade Federal de Santa Maria Centro de Cincias Rurais

Programa de Ps-Graduao em Agronomia

A Comisso Examinadora, abaixo assinada, aprova a Tese de Doutorado

ESCALA FENOLGICA, REA FOLIAR E DESENVOLVIMENTO DE HASTES FLORAIS DE GLADOLO EM FUNO DA

POCA DE PLANTIO

elaborada por Natalia Teixeira Schwab

como requisito parcial para a obteno de grau de Doutor em Agronomia

COMISSO EXAMINADORA:

Nereu Augusto Streck, Dr. (UFSM)

(Presidente / Orientador)

Rogrio Antonio Bell, Dr. (UFSM)

Fernanda Alice Antonello Londero Backes, Dr. (UFSM)

Fernanda Ludwig, Dr. (UERGS)

Claudia Petry, Dr. (UPF)

Santa Maria, 28 de maio de 2014.

OFEREO

Aos meus pais, Luiz Alberto e Beatriz,

Pelo constante exemplo de vida; Por me ensinarem o valor do trabalho, da persistncia e da honestidade;

Pelas tantas vezes que abriram mo de seus sonhos em favor dos meus. Fica aqui a minha gratido, o meu carinho e o amor que sinto por vocs!

AGRADECIMENTOS

Aos meus pais, Beatriz e Luiz Alberto: no tenho palavras para agradecer o

apoio que me deram nesta caminhada. Espero um dia poder retribuir tudo o que

fizeram por mim.

Professor Nereu Augusto Streck: agradeo a oportunidade cedida, a

confiana depositada e os ensinamentos que levarei para a vida.

Professores Rogrio Antonio Bell e Fernanda Alice Antonello Londero

Backes: gostaria de expressar minha gratido pelo apoio, carinho e cumplicidade.

Fotgrafo e amigo Patrcio Orozco Contreras: reconheo enormemente sua

contribuio tcnica e artstica para a construo deste trabalho.

Aos colegas de laboratrio: agradeo a troca de experincia e amizade em

especial aos que mais de perto acompanharam este trabalho - Camila Becker, Bruna

Ribeiro, Lilian Uhlmann, Josana Langner, Giovana Ribas, Charles Oliveira, Eduardo

Wink e Luana Gabriel. Recordaes da sala 2 sero eternas.

Por fim, agradeo a CAPES pela bolsa de estudos e tambm aos programas

PIBIC/CNPq/UFSM e PIBIC-EM/CNPq/UFSM pelas bolsas de Iniciao Cientfica.

A Universidade Federal de Santa Maria, pelos longos anos de acolhimento.

Desta instituio levo o orgulho de ter feito parte.

Homens convictos so prisioneiros.

Friedrich Nietzsche

RESUMO

Tese de Doutorado

Programa de Ps-Graduao em Agronomia Universidade Federal de Santa Maria

ESCALA FENOLGICA, REA FOLIAR E DESENVOLVIMENTO DE HASTES FLORAIS DE GLADOLO EM FUNO DA POCA DE

PLANTIO

Autor: Natalia Teixeira Schwab Orientador: Nereu Augusto Streck

Data e Local de Defesa: Santa Maria, 28 de maio de 2014.

O gladolo uma importante flor de corte cultivada em vrios pases do mundo e, no Brasil, esta cultura florcola de grande relevncia comercial, especialmente em Finados, mas trabalhos relacionados sua biologia ainda so escassos. Estudos sobre a fenologia dos cultivos agrcolas so importantes, pois fornecem informaes para a definio do manejo e tratos culturais adequados espcie, os quais so determinantes na produo e qualidade final do produto. Os objetivos foram: (a) propor uma escala fenolgica para a cultura do gladolo, que seja visvel a olho nu, com critrios no destrutivos e facilmente identificveis a campo; (b) determinar um modelo matemtico emprico que melhor estime a rea da folha do gladolo a partir de dimenses lineares e aplicar o modelo matemtico para determinar o perfil vertical da rea das folhas em diferentes posies na planta; (c) sugerir um termo para representar o intervalo de tempo entre a abertura de botes florais sucessivos em inflorescncias e testar a aplicabilidade deste termo em gladolo de corte; (d) determinar as pocas de cultivo em que possvel produzir hastes de gladolo cultivado em ambiente subtropical que atendam aos padres comerciais do mercado nacional de flores de corte. Ensaios de campo com diversas cultivares, alm de dois experimentos campo com 12 pocas de plantio e trs cultivares de gladolo em cada experimento foram conduzidos para se testar e alcanar os objetivos acima propostos, atravs de observaes e mensuraes dirias. Os resultados obtidos possibilitaram a construo de uma escala fenolgica para a cultura do gladolo, a determinao de um modelo linear capaz de estimar a rea de folhas de gladolo, a determinao de um termo adequado para descrever o desenvolvimento floral (antocrono) e a determinao das pocas mais apropriadas para o cultivo do gladolo com vistas a obteno de hastes florais com melhores parmetros quantitativos, relativos ao padro comercial, nas condies do Rio Grande do Sul. Palavras-chave: Gladiolus x grandiflorus Hort. Fenologia. rea de folhas. Antocrono. poca de plantio.

ABSTRACT

Doctoral Thesis

Graduate Program in Agronomy Federal University of Santa Maria

PHENOLOGICAL SCALE, LEAF AREA AND FLORAL STEMS DEVELOPMENT OF GLADIOLUS AS A FUNCTION OF

PLANTING DATE

Author: Natalia Teixeira Schwab Advisor: Nereu Augusto Streck

Date and Place of defense: Santa Maria, May 28th, 2014.

Gladiolus is an important cut flower cultivated in several countries worldwide and, in Brazil, this floricultural crop is commercially important, especially in All Souls Day, but its studies on its biology are still scarce. Studies on the phenology of crops are important because they provide information to define the management and cultural practices appropriate for the species, which are crucial in the production and final product quality. The objectives are: (a) to propose a phenological scale for growing gladiolus, which is visible to the naked eye, with non - destructive criteria and easily identifiable in the field; (b) to determine an empirical mathematical equation that better estimates the area of individual leaves of gladiolus from linear dimensions and apply the mathematical model to determine the vertical profile of leaves area at different positions on the plant; (c) to suggest a term to represent the time interval between the opening of successive of floral buds and inflorescences and test the applicability of the term to cut gladiolus; and (d) to determine the planting dates in which it is possible to produce stems of gladiolus grown in subtropical environment that meet commercial standards of the national market of cut flowers. Field trials with different cultivars, and two field experiments with 12 planting dates and three cultivars in each experiment were conducted to test and estimate the above proposed objectives through daily observations and measurements. Results allowed the construction of a phenological scale for gladiolus, the determination of a linear model capable to estimating the leaf area of gladiolus, determining an appropriate term to describe the floral development and determining the most appropriate months for planting gladiolus in order to obtain floral stems with commercial quality in Rio Grande do Sul clime conditions, Brazil. Key-words: Gladiolus x grandiflorus Hort. Phenology. Leaf area. Antochron. Planting date.

LISTA DE SMBOLOS

S0 Cormo Dormente

S1 Aparecimento das razes

S2.1 Aparecimento do primeiro catfilo

S2.2 Aparecimento do segundo catfilo

S2.3 Aparecimento do terceiro catfilo

VE Emergncia

V1 Primeira folha

V2 Segunda folha

V3 Terceira folha

Vn Ensima folha

VF Folha bandeira

R1.0 Incio do espigamento

R1.1 Metade do espigamento

R1.2 Espigamento completo

R2 Desenvolvimento dos botes florais

R3 Incio da Antese

R3.4 Metade da Antese

R3.5 Incio da senescncia da haste floral

R3.6 Metade da senescncia da haste floral

R4 Final da Antese

R5 Senescncia completa da haste floral

R6 Senescncia da planta

SUMRIO

1 INTRODUO ....................................................................................................... 19

2 REVISO DE LITERATURA ................................................................................. 21

2.1 Gladiolus sp. ........................................................................................................ 21

2.2 Escalas de desenvolvimento das culturas agrcolas ........................................... 23

2.3 Efeito de pocas de plantio sobre o desenvolvimento de culturas agrcolas ...... 26

2.4 Estimativa da rea de folhas em culturas agrcolas ............................................ 27

2.5 Objetivos ............................................................................................................. 28

2.6 Hipteses ............................................................................................................ 29

3 CAPTULO I A PHENOLOGICAL SCALE FOR THE DEVELOPMENT OF

GLADIOLUS ............................................................................................................. 31

3.1 Abstract ............................................................................................................... 31

3.2 Introduction .......................................................................................................... 32

3.3 Material and Methods .......................................................................................... 34

3.4 Results ................................................................................................................ 37

3.5 Discussion ........................................................................................................... 39

3.6 References .......................................................................................................... 44

4 CAPTULO II DIMENSES LINEARES DA FOLHA E SEU USO NA

DETERMINAO DO PERFIL VERTICAL FOLIAR DE GLADOLO ...................... 57

4.1 Resumo ............................................................................................................... 57

4.2 Introduo ........................................................................................................... 58

4.3 Material e Mtodos .............................................................................................. 59

4.4 Resultados e Discusso ...................................................................................... 63

4.5 Concluso ........................................................................................................... 67

4.6 Referncias ......................................................................................................... 67

5 CAPTULO III ANTOCRONO: UM TERMO PARA REPRESENTAR O

DESENVOLVIMENTO FLORAL EM INFLORESCNCIAS ..................................... 75

5.1 Resumo ............................................................................................................... 75

5.2 Introduo ........................................................................................................... 76

5.3 Material e Mtodos .............................................................................................. 77

5.4 Resultados e Discusso ...................................................................................... 79

5.5 Concluso ........................................................................................................... 82

5.6 Referncias ......................................................................................................... 82

6 CAPTULO IV PARMETROS QUANTITATIVOS DE HASTES FLORAIS DE

GLADOLO CULTIVADO EM DIFERENTES DATAS DE PLANTIO ........................ 91

6.1 Resumo ............................................................................................................... 91

6.2 Introduo ........................................................................................................... 91

6.3 Material e Mtodos ............................................................................................. 93

6.4 Resultados e Discusso ..................................................................................... 95

6.5 Concluso ......................................................................................................... 100

6.6 Referncias ....................................................................................................... 100

7 DISCUSSO GERAL .......................................................................................... 111

8 CONCLUSES ................................................................................................... 127

REFERNCIAS BIBLIOGRFICAS ...................................................................... 129

APNDICES ........................................................................................................... 135

1 INTRODUO

A floricultura uma atividade do setor agrcola altamente tecnificada e

rentvel, que utiliza intensivamente mo-de-obra e apresenta alta competitividade de

mercado, sendo possvel sua aplicao em pequenas reas ou, at mesmo, em

reas consideradas imprprias para cultivos agrcolas convencionais (SCHWAB,

2011). Os produtos da floricultura apresentaram movimento comercial internacional

estimado, no ano de 2010, de US$ 20,2 bilhes, e neste mesmo ano, no Brasil, o

setor foi responsvel por movimentar em torno de US$ 3,8 bilhes, com destaque

exportao de materiais propagativos, como cormos de gladolo (JUNQUEIRA;

PEETZ, 2011), o que constitui considervel participao nacional neste mercado.

O gladolo (Gladiolus x grandiflorus Hort.) uma importante flor de corte

cultivada na maioria dos pases tropicais e subtropicais (AHMAD et al., 2011), e vem

apresentando destaque no comrcio internacional de flores, sendo que em 2008

ocupava a oitava posio mundial no comrcio de flores de corte (AHMAD; AHMAD;

QASIM, 2008), passando para a quarta posio, em 2012 (SINGH et al., 2012).

uma flor de corte que produz altos retornos financeiros para produtores ao redor do

mundo (CHANDEL; DEEPIKA, 2010).

No Brasil, por volta da dcada de 50, o gladolo comeou a ser cultivado por

imigrantes holandeses, tornando-se o primeiro produto florcola a ser explorado

pelos produtores de Holambra (SP), passando a ser a principal atividade econmica

(TOMBOLATO et al., 2005). Atualmente, no Brasil, a espcie apresenta particular

importncia comercial em Finados, data de maior consumo.

Apesar da importncia do gladolo para a floricultura nacional e mundial, at o

momento so escassas as pesquisas relacionadas sua biologia, sendo dados

encontrados na literatura respeito do desenvolvimento pouco detalhados. Em

estudos relacionados biologia das espcies, importante que o desenvolvimento

vegetal seja descrito e quantificado, pois tal processo refere-se diferenciao de

clulas e iniciao e aparecimento de rgos, podendo se estender durante todo o

ciclo da planta at a senescncia (HODGES, 1991; WILHELM; McMASTER, 1995).

Diferentemente de outras culturas agrcolas, como milho (HANWAY, 1966; RITCHIE

et al., 1993), trigo (LARGE, 1954), soja (FEHR; CAVINESS, 1977) e arroz (COUNCE

20

et al., 2000), e mesmo florcolas como a rosa (MEIER et al., 2009b), no foi

encontrada na literatura uma escala fenolgica para a cultura do gladolo. Tambm

aspectos relacionados rea de folhas e desenvolvimento floral para essa espcie

devem ser objeto de estudos cientficos, pois, em conjunto, podem fornecer

informaes relevantes para o manejo da cultura (GRAMBONE-GUARATINI et al.,

2004).

Na literatura reportado que o cultivo do gladolo pode ser realizado ao longo

do ano todo (BARBOSA et al., 2011). Porm, em condies de inverno nas regies

subtropicais, como o caso do Rio Grande do Sul, eventos de baixa temperatura,

como as geadas, e diminuio da luminosidade podem causar redues de

produtividade, ficando, dessa forma, o cultivo de gladolo condicionado a perodos

com condies climticas mais indicadas para a cultura, o que deve ser investigado.

Esta tese est dividida em quatro captulos. No Captulo I proposta uma

escala fenolgica para a cultura do gladolo; No Captulo II so apresentadas

equaes empricas para a estimativa da rea de folhas individuais de gladolo; No

Captulo III proposto um termo para descrever o desenvolvimento floral em gladolo

(antocrono) em analogia ao filocrono (usado para descrever o desenvolvimento

foliar); No Captulo IV feita uma anlise dos parmetros quantitativos de hastes

florais de gladolo em funo da poca de plantio em ambiente subtropical.

2 REVISO DE LITERATURA

2.1 Gladiolus sp.

O gnero Gladiolus complexo dentro da famlia das Iridceas (ESPINOSA

et al., 2003). tido como o maior gnero conhecido de monocotiledneas

petalides, ocorrendo em maior concentrao na regio mediterrnea e sul da

frica, onde existem mais de 100 espcies de gladolos silvestres (GREVIG, 1987;

TOMBOLATO et al., 2005; RIAZ et al., 2010).

As cultivares de gladolo de corte atualmente cultivadas pertencem ao gnero

Gladiolus, espcie grandiflorus, ordem Iridales, famlia Iridaceae, sub-famlia

Iriodae e apresentam inflorescncia do tipo espiga (POON et al., 2009). uma

espcie hbrida, comercialmente empregada como flor de corte e, ocasionalmente

utilizada no paisagismo na construo de macios. As cultivares so obtidas por

meio de hibridaes, resultando em gentipos que apresentam grande variedade de

cores de inflorescncias e variabilidade em relao ao perodo de tempo necessrio

para a florao (POON et al., 2009). Tais hibridaes so originadas de um

complexo intercruzamento de, pelo menos, 11 espcies, representadas por

diferentes formas, cores e variedades botnicas (TOMBOLATO et al., 2005).

As folhas do gladolo so lanceoladas e partem das gemas axilares do cormo,

podendo variar em nmero de um a doze. A haste herbcea, composta por uma

inflorescncia do tipo espiga1, rgo de interesse comercial. A espiga formada de

floretes que so conectados diretamente ao eixo central, chamado rquis, podendo

atingir um nmero acima de trinta floretes por espiga. Nos floretes, os trs

segmentos mais externos formam o clice2 e o verticilo de trs segmentos seguintes

compreende a corola3. O perianto4 circunda trs estames e um pistilo tricarpelado

com um estigma trifurcado. O ovrio contm entre 75 e 150 vulos. Cada boto floral

1 Espiga: tipo de inflorescncia composta por flores ssseis, distribudas ao longo de uma haste.

2 Clice: conjunto de spalas de uma flor.

3 Corola: conjunto de ptalas de uma flor.

4 Perianto: conjunto composto por clice e corola.

22

encerrado separadamente com sua prpria espata, que consiste de duas brcteas

verdes (TOMBOLATO et al., 2005; POON et al., 2009; AHMAD et al., 2011).

Os floretes de gladolo podem possuir vrias cores, dependendo da cultivar,

apresentam simetria bilateral ou radial e as ptalas podem ser planas, onduladas,

lacinadas, recurvadas ou pontiagudas. Os floretes podem apresentar tamanhos

variados (de 2 cm a 18 cm de dimetro), disposto em espigas compactas ou laxas,

com caule nico ou ramificado (TOMBOLATO et al., 2005), dependendo da cultivar.

O material propagativo comercialmente utilizado um bulbo slido,

denominado botanicamente de cormo, que se constitui em um caule subterrneo de

reserva. Durante o perodo em que a planta encontra-se dormente, esta estrutura

tem capacidade de mant-la viva, at que o desenvolvimento seja retomado, o que,

nos centros de origem da espcie, ocorre aps o incio das chuvas de primavera

(AHMAD et al., 2011).

Aps o plantio, o cormo (cormo-me ou cormo velho) comea a produzir em

sua parte superior um novo cormo (ou cormo-filho) e inicia um processo de secagem

e morte de seus tecidos, chamado mumificao. O desenvolvimento das folhas

ocorre na parte superior do novo cormo formado e a base destas passa a recobrir o

mesmo, formando escamas, que sobrepem umas as outras e agrupam-se em um

ponto na parte superior do cormo. Enquanto o novo cormo (cormo-filho) est se

formando sobre o cormo-me, pequenas estruturas propagativas, chamadas

cormilhos, so produzidas na base deste (LARSON, 1992). Cormos e cormilhos

(Figura 2.1) so as principais maneiras de propagao do gladolo, enquanto as

sementes so utilizadas como material propagativo em programas de melhoramento.

Usualmente os produtores de gladolo de corte compram cormos de empresas

especializadas, os quais j foram submetidos ao processo de quebra de dormncia

por frio (vernalizao).

As cultivares comerciais existentes no mercado podem ser colhidas com a

maioria dos botes ainda fechados, j que o melhoramento gentico possibilitou a

abertura normal destes aps a colheita, quando mantidos em vaso com gua

(TOMBOLATO et al., 2005). As hastes colhidas devem permanecer na posio

vertical, para evitar que o geotropismo negativo, caracterstico da espcie, cause

problemas de tortuosidade nas hastes, o que pode desclassific-las para a venda,

conforme descrito pelos padres Veilling Holambra (2013).

23

Figura 2.1. Esquema ilustrando as estruturas de propagao vegetativa de gladolo. Santa Maria, 2014.

2.2 Escalas de desenvolvimento das culturas agrcolas

A descrio das etapas de crescimento e desenvolvimento das plantas

sempre foi uma questo de interesse da pesquisa, sendo reportada desde perodos

bastante remotos, como apresentado em manuscritos que datam 750 d.C. e

apresentam registros sobre o perodo de florao das cerejeiras no Japo (MORAIS

et al., 2008). Quando espcies vegetais ou animais tm seus processos de

crescimento e desenvolvimento como objeto da pesquisa, estes so organizados e

descritos atravs de escalas fenolgicas ou escalas de desenvolvimento, que

utilizam nomenclaturas prprias para descrever o ciclo de vida das espcies. Estas

escalas de desenvolvimento tm como objetivo uniformizar a comunicao entre os

envolvidos em atividades agrcolas e tambm representar a idade fisiolgica das

plantas para fins de manejo das lavouras.

Para Meier et al. (2009a), a fenologia o estudo dos eventos no ciclo de vida

de planta ou animais, sendo que estes eventos so influenciados, em diferentes

nveis, por fatores ambientais. Atualmente, o conhecimento da fenologia das

espcies de grande importncia, e partir dele possvel realizar o planejamento

24

das pocas apropriadas para a realizao de diversas prticas culturais (ARCILA et

al., 1998), bem como na estimativa de safra e previso da poca de maturao

(PEZZOPANE et al., 2003).

No caso de espcies agrcolas, o ciclo de desenvolvimento geralmente

dividido em duas fases, vegetativa e reprodutiva, podendo haver maior detalhamento

destas e a incluso, na descrio da escala, de fases como dormncia, brotao,

maturao, entre outros, dependendo das particularidades de cada espcie.

Comumente, para espcies vegetais, durante a fase vegetativa computada a

emisso de folhas sucessivas no cartucho da planta at a emisso e expanso da

ltima folha ou folha bandeira. Durante a fase reprodutiva, descrito o

desenvolvimento dos rgos relacionados a reproduo das espcies, tais como

flores, frutos e sementes, podendo esta fase se estender at a senescncia

completa da planta.

Espcies agrcolas como soja (FEHR; CAVINESS, 1977), milho (HANWAY,

1966), trigo (LARGE, 1954) e arroz (COUNCE et al., 2000), apresentam vasta

literatura que descreve em detalhes os eventos ocorrentes durante seu ciclo de vida,

denominados estgios de desenvolvimento. Os estgios de desenvolvimento

geralmente so caracterizados pela data de aparecimento de um rgo na planta,

sendo que o intervalo de tempo entre os estgios denominado fase de

desenvolvimento (STRECK et al., 2003 a).

Para culturas florcolas, esto disponveis na literatura a descrio de

algumas escalas de desenvolvimento, como para rosa (MEIER et al., 2009b) e znia

(GONALVES et al., 2008) porm, para a cultura do gladolo, apenas relatos pouco

detalhados sobre o desenvolvimento da espcie foram encontrados (TRINKLEIN,

2005; CUEVAS,1999; PAIVA et al., 1999; HARTLINE, s.d) e, por isso, julgou-se

necessria a construo de uma escala de desenvolvimento para a cultura.

Na Tabela 2.1 so apresentados esquemas encontrados na literatura que

descrevem de modo simplificado o ciclo de desenvolvimento do gladolo. Tais

esquemas enfatizam o desenvolvimento da parte da planta que fica abaixo do solo,

no possibilitando especificaes aprofundadas do desenvolvimento da parte area.

25

Tabela 2.1. Esquemas encontrados na literatura em que representado o ciclo de desenvolvimento do gladolo. Santa Maria, RS, 2014.

Referncias Ciclo de desenvolvimento do gladolo segundo literatura

TRINKLEIN (2005)

CUEVAS (1999)

PAIVA et al. (1999)

HARTLINE (s.d.)

26

2.3 Efeito de pocas de plantio sobre o desenvolvimento de culturas agrcolas

A escolha da poca de semeadura ou plantio para uma espcie definida por

um conjunto de fatores ambientais que interagem com a planta e,

consequentemente causam variaes na produo e afetam as caractersticas

agronmicas da cultura (PEIXOTO et al., 2000). Cultivares, quando

semeadas/plantadas em diferentes pocas, expressam suas potencialidades de

forma variada, como resultado da sua resposta s condies do ambiente (BARROS

et al., 2003). Como os fatores ambientais variam de ano para ano, so necessrios

ensaios com cada gentipo para quantificar a resposta destes s interaes

ambientais (PELUZIO et al., 2008). Para flores de corte, a programao das datas

de plantio tem papel crucial no atendimento da demanda do mercado consumidor.

Quando essa programao adequada, o abastecimento do mercado atendido,

principalmente para datas comemorativas, quando a necessidade dos consumidores

por produtos da floricultura maior.

Uma srie de trabalhos, ainda na dcada de 70, demonstrou que variaes

nas condies ambientais, tais como intensidade luminosa, comprimento do dia,

temperatura e umidade do solo, podem influenciar o desenvolvimento e produo de

hastes florais de gladolo (SHILLO; HALEVY, 1976a; SHILLO; HAVELY, 1976b;

SHILLO; HAVELY, 1976c; SHILLO; HAVELY; 1976d). Segundo Zubair et al. (2006),

o momento da florao do gladolo bastante previsvel quando o plantio realizado

em uma poca que apresente condies ambientais adequadas para o

desenvolvimento da cultura, o que auxilia o produtor na programao da data de

plantio e, consequentemente, na data de colheita das hastes, conforme a demanda

do mercado.

Alguns trabalhos reportam que o gladolo pode ser cultivado ao longo de

todas as pocas do ano (BARBOSA et al., 2011), porm, em alguns perodos,

podero ocorrer problemas no cultivo, principalmente se houver reduo de

luminosidade e temperatura, condies tpicas do perodo invernal de regies

subtropicais. Dessa forma, se faz necessria a realizao de pesquisas em regies

subtropicais onde sejam experimentados plantios em todas as pocas do ano, a fim

de definir qual dessas pocas possibilita cultivo rentvel e de qualidade para o

gladolo.

27

2.4 Estimativa da rea de folhas em culturas agrcolas

Segundo Leme et al. (1984), a produo em culturas agrcolas est

diretamente relacionada ao aproveitamento da energia solar, que por sua vez

transformada em energia qumica durante o processo fotossinttico. O

aproveitamento da radiao solar depende da sua interceptao pelo dossel vegetal,

o qual tem relao direta com a rea de folhas da planta, que consequentemente

sero as estruturas responsveis pela produo de fotoassimilados, que implicaro

na produtividade biolgica da cultura (STRECK et al., 2003a).

durante a fase vegetativa das culturas que h o aumento da rea de folhas,

importante na interceptao de radiao solar para a fotossntese. Os

fotoassimilados produzidos durante esta fase so empregados, no caso do gladolo,

para a formao e crescimento de novas folhas, crescimento da espiga floral, razes,

cormo novo e cormilhos, que ocorrem durante a fase reprodutiva (SHILLO; HAVELY,

1976e).

Segundo Marshall (1986), a rea foliar de uma cultura ir depender do

nmero e do tamanho das folhas da planta, e pode ser determinada a partir de

mtodos de medio destrutivos (diretos) ou no destrutivos (indiretos). Fagundes

et al. (2009) citam, dentre os mtodos destrutivos utilizados para a determinao da

rea foliar, o dos discos foliares (em que a rea foliar real estimada por meio de

vazadores com rea conhecida e do peso do restante da folha), o da pesagem das

silhuetas (em que feita a comparao entre o peso de uma rea conhecida de

papel com densidade definida e os pesos das silhuetas das folhas sobre eles), o da

medio direta (realizada com uso de medidores automticos de rea foliar), e o

gravimtrico ou planimtrico. J dentre os mtodos no destrutivos encontram-se

aqueles em que a rea foliar estimada por meio de medidas lineares tomadas nas

folhas (comprimento x largura mxima) pela equao de regresso linear entre as

medidas lineares tomadas na folha e um mtodo padro, realizado em laboratrio ou

por meio de um fator de correo (K),calculado do quociente entre o somatrio das

reas calculadas pelo mtodo padro e o somatrio das reas calculadas pelas

medidas lineares das folhas.

Dentre os mtodos citados para a determinao da rea foliar, o mtodo da

regresso linear j foi utilizado para diversas culturas agrcolas, tais como girassol

28

(AQUINO et al., 2011), batata (SILVA et al., 2008), feijo-caupi (LIMA et al., 2008),

feijo-vagem (TOEBE et al., 2012), couve-folha (MARCOLINI et al., 2005) e consiste

em realizar uma regresso linear entre essas duas variveis (comprimento x largura

mxima), forando-se a reta a passar na origem (coeficiente linear nulo). Isso

permite estimar o quociente entre a rea real e o produto do comprimento pela

largura mxima (coeficiente angular) e, a partir desse quociente, chamado de fator

de correo, possvel estimar a rea de qualquer folha de uma mesma espcie,

ao ser multiplicado pelo produto de suas dimenses lineares (comprimento x largura

mxima) (CLEMENTS; GOLDSMITH, 1924; DARROW, 1932).

2.5 Objetivos

O objetivo geral contribuir para aumentar o conhecimento sobre o

desenvolvimento do gladolo e que este futuramente sirva para auxiliar no

entendimento do manejo da cultura e incrementar a produtividade de hastes de

gladolo.

Os objetivos especficos so:

(a) propor uma escala fenolgica para a cultura do gladolo, baseada em

indicadores que sejam visveis a olho nu, com critrios no destrutivos e

facilmente identificveis a campo;

(b) determinar um modelo matemtico emprico que melhor estime a rea da

folha do gladolo a partir de dimenses lineares e aplicar o modelo

matemtico para determinar o perfil vertical da rea das folhas em diferentes

posies na planta;

(c) sugerir um termo para representar o intervalo de tempo entre a abertura de

botes florais sucessivos em inflorescncias e testar a aplicabilidade deste

termo em gladolo de corte;

(d) determinar as pocas de cultivo em que possvel produzir hastes de gladolo

cultivado em ambiente subtropical que atendam aos padres comerciais do

mercado nacional de flores de corte.

29

2.6 Hipteses

a) possvel construir uma escala de desenvolvimento no destrutiva para o

gladolo a partir de observaes de campo, relatando e apontando as

modificaes morfolgicas durante o ciclo de desenvolvimento da cultura.

b) possvel determinar um modelo matemtico emprico que estime rea da

folha do gladolo a partir de dimenses lineares.

c) possvel descrever e testar um termo que representa o intervalo de tempo

entre a abertura de botes florais sucessivos em inflorescncias.

d) possvel determinar as pocas de cultivo em ambiente subtropical que

sejam produzidas hastes de gladolo que atendam aos padres comerciais do

mercado nacional de flores de corte.

3 CAPTULO I A PHENOLOGICAL SCALE FOR THE

DEVELOPMENT OF GLADIOLUS

Artigo submetido revista Annals of Applied Biology em 20/01/2014.

Situao atual: com os autores para atender aos comentrios e sugestes dos

revisores.

3.1 Abstract

A staging system for development of gladiolus (Gladiolus x grandiflorus Hort.) that

relies on easy, naked-eye, non-destructive and fast criteria was proposed. Four field

trials were conducted during the spring 2010, fall/winter 2011 and winter 2011 at

Santa Maria, RS, Brazil, with different gladiolus cultivars, in order to observe the

developmental stages of the above-ground parts and their dry matter. The

developmental cycle, which starts at dormant corm and ends with plant senescence,

is divided into four developmental phases: dormancy phase, sprouting phase (from

filiform roots appearance to sheaths appearance), vegetative phase (from emergence

of the first leaf tip to emergence of the final leaf tip on the stem) and reproductive

phase (from flower initiation to plant senescence). The developmental stages during

the dormancy phase and during the sprouting phases are coded as S-stages: S0 =

Dormant corm, S1 = Appearance of roots, S2.1 = First sheath, S2.2 = Second sheath

and S2.3 = Third sheath. Vegetative phase is coded as V-stages: VE = emergence

of the sheaths above ground, V1 = first leaf, V2 = second leaf, Vn = nth leaf and VF=

flag leaf. Leaf tip is the marker for V1 to VF. The developmental stages during the

reproductive phases are coded as R-stages: R1 = heading, R2 = blooming, R3 =

onset of flowering, R4 = end of anthesis, R5= end of florets senescence and R6 =

plant senescence (leaves and florets axis are brown). Sub-stages have also been

assigned between R1 and R2 and between R3 and R4. Illustrations (photographs) of

each developmental stage taken from field pot-grown plants are provided in the

paper and the proposed scale was tested with field observations. The proposed

32

system is an easy, visible, non-destructive and fast tool for both practical purposes by

farmers and for research purposes in experimental trials.

Key words: Gladiolus x grandiflorus, morphological criteria, phenology,

developmental scale, developmental stages, floriculture.

3.2 Introduction

Gladiolus or sword lily (Gladiolus x grandiflorus Hort.), Iridaceae family, is an

important cut flower propagated from corms (solid bulbs). Gladiolus is considered the

genus with the largest known number of species with the petaloid monocots,

occurring naturally mainly in the Mediterranean and Southern Africa regions, where

there are more than 100 wild species of gladiolus (Greving, 1987; Tombolato et al.,

2005; Riaz et al., 2010). The marketable flower of gladiolus is botanically a long one-

sided spike with many florets. The flowers of the different gladiolus cultivars come in

a variety of colours. In addition to growing it as a cut flower, the beautiful blossom of

gladioli may also be used to compose flowerbeds in colourful gardens (cottage style)

such as in the reconstructed Monets garden at Giverny, France (Willery, 2010).

Even though gladiolus is grown in many tropical, subtropical and temperate

regions worldwide (Ahmad et al., 2011), detailed studies on the phenology of

gladiolus are scarce. Previous studies on gladiolus phenology have been dedicated

more to describe the below-ground development (Trinklein, 2005) whereas the

above-ground development has been described with fewer details (Cuevas, 1999). A

detailed description of the above-ground development for gladiolus is important for

basic studies on the biology and phenology of the species as well as for practical

purposes, such as the timing of field management practices like nitrogen side

dressing, harvest scheduling, and disease and insects control (Greving, 1987; Smith,

2006). Therefore, a better understanding of gladiolus phenology has the potential to

improve flower quality and minimize environmental impacts in commercial production

systems.

Phenology is the study of development (Hodges, 1991). Plant development

can be defined as a process by which individuals or organs go through several

33

identifiable stages during their life cycle (Wilhelm & McMaster, 1995), and includes

cell differentiation and organ initiation and appearance, and may extend throughout

the plant cycle until senescence (Hodges, 1991; Wilhelm & McMaster, 1995). Meier

et al. (2009a) defined phenology as the study of the events in the life cycle of animals

and plants, and these events are influenced by environmental factors. A

developmental stage is usually characterized by the appearance (morphogenesis) of

an organ while the interval of time between two stages is defined as a developmental

phase (Streck et al., 2003). An organ can appear to the observer either to the

naked eye or under some magnification (small hand lens or a microscope).

The description of plant developmental stages has been of interest for

centuries with records dating from A.D. 750 on the flowering period of cherry trees in

Japan (Morais et al., 2008). Once the relevant developmental events in a plants life

cycle are determined, their sequence can be assembled into a developmental or

phenological scale with stages designating those events. Developmental staging

systems are useful tools to standardize communication between those involved in

agricultural activities such as farmers, consultants, extensionists, crop insurers,

educators and scientists, and are an aid in information for crop management

practices (Counce et al., 2000). Developmental scales have four main parts: the

name of the developmental phases, the name of the developmental stages within

each developmental phase, a code (a number, a set of letters or a combination of

letters and numbers) of the developmental stages, and a description (criteria) of each

developmental stage (Zadoks et al., 1974; Fehr & Caviness, 1977; Counce et al.,

2000).

Developmental scales have been proposed for several agricultural crops,

including annual grain crops like soybean (Fehr & Caviness, 1977), maize (Hanway,

1966; Ritchie et al., 1993), wheat (Large, 1954; Zadoks et al., 1974) and rice

(Counce et al., 2000), and fruit crops such as persimmon tree (Garcia-Carbonell et

al., 2002), olive tree (Snz-Corts et al., 2002), coffee tree (Morais et al., 2008) and

mango tree (Delgado et al., 2011). Some flower crops also have phenological scales

such as Rosa sp. (Meier et al., 2009b) and Zinnia elegans (Gonalves et al., 2008).

The BBCH system (Biologische Bundesanstalt, Bundessortenamt and CHemical

industry) includes a scale for bulb vegetables, not for bulb flowers (Feller et al.,

1995). Bulb vegetables (onion, garlic) are biennials whereas bulb flowers, including

gladiolus, are perennials and they differ greatly in development, so the BBCH scale

34

for bulb vegetables in not suitable for gladiolus. We are unaware of a comprehensive

and adaptive staging system for gladiolus, which constituted the rationale for

developing a phenological scale for this flower crop.

With regard to the coding approach, we opted for presenting a staging system

for gladiolus where the code is comprised by a letter and a number, following the

widely used coding systems of maize (Ritchie et al., 1993), soybean (Fehr &

Caviness, 1977) and rice (Counce et al., 2000), where letters represent the

developmental phase and numbers represent the developmental stage. This

approach is easier for end users such as extensionists and growers than a system

coded only with numbers like the Zadoks scale (Zadoks et al., 1974) and the BBCH

system (Meier et al., 2009a).

The objective of this study was to propose a staging system for describing the

development of gladiolus that relies on easy naked eye, non-destructive and fast

criteria.

3.3 Material and Methods

A plant development system has to have four main features (Counce et al.,

2000): (a) dichotomous criteria based on plant morphogenesis (i.e. discrete

morphological criteria which are either present or absent) to identify developmental

stages and phases; (b) based on actual events rather than indications; (c) wide range

of application rather than local applications, and (d) visibility of criteria, naked-eye

markers or with a small hand lens (about 10x magnification) are preferred rather than

requiring a microscope to identify developmental stages. Furthermore, a staging

system should have the vegetative development based on cumulative leaf number

(CLN), which is a biologically sound way to express plant age (Counce et al., 2000).

The Hauns system (Haun, 1973) was the first staging system to formally incorporate

CLN as a continuous developmental stage for wheat. Fehr & Caviness (1977)

incorporate CLN as V-stages in their soybean system recognizing that the vegetative

development overlaps the reproductive development. We considered all the above

requirements in our development system for gladiolus.

35

The approach we used for constructing the development of the staging system

followed the one used by Counce et al. (2000), for developing their rice staging

system, which included laboratory and field experiments where gladiolus corms and

plants were observed as they developed, taking notes of the dates that phenological

events took place on the same plants, studying and updating the literature on plant

development, and discussion with scientists from biology and floriculture disciplines.

As developmental stages were defined (their morphological criteria), at least two

different persons made observations on the plants in the experiments, and if criteria

were not clear (dichotomous and objective), difficult to see or interpreted differently

by different observers, we discussed the criteria until these problems were solved.

Gladiolus morphogenesis was divided into four phases: corm dormancy, bud

sprouting, vegetative and reproductive. Corm dormancy is regulated by internal

growth inhibitors and in commercial production systems dormant corms are stored

under low temperatures (5C) to delay sprouting and at same time vernalized them

(Vidalie, 1990). After corms are planted, roots start to grow from root nodules at the

bottom of the corm (filiform roots), leaf primordial differentiate at the apex of the bud

and usually three leaf sheaths grow from the bud to protect the growing leaves.

Vegetative development occurs by the accumulation of leaves that appear at the

whorl one after other in opposite sides of the shoot. The period between the

appearance of successive leaf tip upwards on the shoot is one phyllochron and can

be easily determined by naked eye. Reproductive development starts with spike

iniciation when the apex is approximately 6mm in length and there are three leaves

visible at the whorl (Shillo & Havely, 1976). Development (differentiation) of florets is

acropetal and the spike is visible at the whorl when 8 to 10 leaves have appeared to

the observed. As the peduncle of the spike elongates above the uppermost leaf (final

leaf number), the rachis also elongates and the distance among florets increases.

Florets open acropetaly on the spike until the uppermost floret; florets senescence

starts at the botton of the spike when about half of the total number of florets are

open and proceeds upwards, until the last floret senesces. Leaves stay green after

florets for some weeks or a few months (photoassimilates produced are devoted to

grow the new corm and the cormels), and eventually senesce, so that the above-

ground parts (leaves and floral axis) are brown (no photosynthetic activity).

The four developmental cycle of gladiolus is divided into four phases:

dormancy and sprouting, which are coded with letters S, and vegetative and

36

reproductive, coded with letters V and R, respectively. Each phase is divided into

several developmental stages coded with a number that follows the letter, so that the

sequence of development can be easily followed. The number denoting the

developmental stages can be either an integer or a decimal.

The developmental stages of the Sprouting phase were observed in five corms

of cultivar Jester, kept in a lab, in dark conditions and temperature of 25-30C, and

laid on a wet cotton mesh, during January 2012. As the developmental stages were

reached, the corms were taken to a professional studio lab and photographed. For

the developmental stages of the above ground parts (vegetative and reproductive

phases), gladiolus plants (cv. Jester) were grown in 3.5 litter pots in open field

conditions at Santa Maria, RS, Brazil (latitude 29 43 23S, longitude 53 43 15W

and altitude 95m), from July 2011 to February 2012. When the developmental stages

were reached, the plants were immediately taken to a professional studio lab and

photographed.

The developmental stages of the above ground parts were observed in three

field trials conducted at the Departamento de Fitotecnia of the Universidade Federal

de Santa Maria (UFSM), in Santa Maria, RS, Brazil. The first trial was carried out

from 08 Sep. 2010 to 29 Dec. 2010 with seven cultivars: T704 (purple), Traderhorn

(red), Sunset (yellow), Jester (yellow and red), Priscilla (pink and white), Peter Pears

(orange), e Rose Supreme (pink). The seven gladiolus cultivars are commonly grown

and representative of the wide range of colours and developmental cycles of

gladiolus cultivars used in Brazil. The second trial was carried out from 30 Mar. 2011

to 31 Dec. 2011 using three cultivars: Traderhorn, T704 and Jester. In these two

trials, observations were made on five plants of each cultivars. The third trial was

carried out from 05 Aug. 2011 to 08 Apr. 2011 using three cultivars (Peter Pears,

T704 and Jester) and observations were performed on 24 plants of each cultivar. The

three trials with plantings at different times of the year allowed evaluating the

repeatability and consistency of the criteria for each developmental stage of the

scale.

In these field trials, commercial vernalized corms were planted in beds with

two rows of plants, 40 cm among rows and 20 cm among plants within the rows, ten

corms per cultivar in the two first trials and forty corms per cultivar in the third trial.

Agronomic practices used by local growers were used during the trials, which

included fertilization, weed control by hoeing, irrigation, and supporting plants

37

vertically with individual bamboo stalks in the first and second trials and with plastic

net in the third trial. Plants were observed daily and the dates of occurrence of the

developmental stages were taken. The criteria for the identification of the

developmental stages were quick and easy-to-view in the field and non-destructive.

While analysing the plants, observers made notes about the difficulties in applying

the criteria to identify each stage of development.

A fourth trial with cultivar Jester planted at 14 Sep. 2012 was conducted in

Santa Maria, RS, Brazil, order to determine dry matter accumulation at each

developmental stage along the development cycle of gladiolus. Corms were planted

in a 10m bed in the same plant spacing and management practices during the trial

were the same used in the previous trials. Plants were observed daily and five plants

were randomly sampled when they reached each successive developmental stage.

The soil was removed from the corm and roots by washing them with tap water.

Sampled plants were separated into leaves, old corm, new corm, cormels, filiform

roots, contractile roots, and floral stem, which were then oven dried at 60C. Dry

matter distribution among the different parts was calculated as a percentage of total

dry matter at each developmental stage.

3.4 Results

The developmental scale for gladiolus is presented in Table 1. Pictures of

each developmental stage are presented in Figures 1 to 7.

The Dormancy phase is visible as a dormant corm which is not yet sprouted

(Stage S0, Figure 1A). There are four stages within the Sprouting phase: S1 (Figure

1B), S2.1 (Figure 1C), S2.2 (Figure 1D), and S2.3 (Figure 1E). In the field, the

developmental stages of the sprouting phase occur in the soil.

The vegetative phase starts when the shoot (usually composed by three

sheaths) emerges from the soil surface. Vegetative developmental stages are

designated as V-Stages, beginning at VE (emergence of the sheaths above the

ground) and extends until the last leaf (here called the flag leaf as in other monocots)

is visible. After VE, the number in the code denotes the number of true (foliage)

leaves above the last sheath, i.e. the cumulative leaf number, so that a plant at V1

38

has one leaf, V2 two leaves and so forth until the final (flag) leaf is visible (VF). The

marker for V1 to VF is when the leaf tip is visible to the observer, i.e. the leaf tip

appearance. Pictures of gladiolus plants at VE, V1, V2, V3, V6 and VF are in Figures

2A, 2B, 2C, 2D, 2E and 2F, respectively.

The reproductive phase starts in the proposed staging system when the spike

is first visible at the whorl and ends when the plant senesces, and developmental

stages are denoted as R-Stages. Heading (when the tip of the spike is visible at the

whorl), Blooming (when florets show the colour of the corolla), Anthesis (florets are

open and anthers are visible) and Florets Senescence (when the corolla dehydrates

and dies) are major developmental stages, with some divisions within them (Table 1).

Pictures of plants at R1.0, R1.1 and R1.2 are in Figure 3A, 3B and 3C, respectively.

Plants at R2 and at R3 are in Figure 4A and 4B, respectively. As florets continue its

opening upwards on the spike after R3, when the floret at the middle position of the

spike is open, the plant is at R3.4 (Figure 5A). When the first floret at the bottom of

the spike starts to senesce, plant is at R3.5 (Figure 5B) and when the floret at the

middle position of the spike senesces, plant is at R3.6 (Figure 5C). Florets opening

continues on the spike until the last floret opens (R4, Figure 6A) and so does the

floret senescence until the last floret senesces, when plant is at R5 (Figure 6B). At

the end of the developmental cycle, the whole plant is senesced, i.e., all leaves and

floral axis are brown with no photosynthetic activity, and this is the stage R6 (Figure

7).

The developmental sequence of gladiolus, with illustrations of the

developmental stages, is presented in Figure 8. The morphological criteria for R1.0,

R1.1 and R1.2 stages are shown in details. Also shown in Figure 8 is the floret

initiation stage (R0) at V3 and its identification is only possible by dissecting the plant

and under magnification (14 x), as the apex in only about 6mm in length (Shillo &

Havely, 1976). In Brazil, a major holiday for gladiolus consumption is the All Souls'

Day (02 November). In order to have marketable flowers for this holiday, planting is

usually done during the second half of July, V-stages occur from end of August to

mid-October, and R3 has to occur 2 to 4 days before the holiday.

The number of days after planting to reach each developmental stages of the

vegetative phase (V-stages) and the reproductive phase (R-stages) in plants of the

field trials is in Table 2, 3 and 4. In the first trial (planting on 08/09/2010) the stages

R1.1, R1.2, R3.4, R3.5, R3.6, R5 and R6 were not observed (Table 2), in the second

39

trial (planting on 30/03/2011) the stages R1.1, R1.2, R3.4, R3.6, R5 and R6 were not

observed (Table 3) and in the third trial (planting on 05/08/2011) only the R3.6 stage

was not observed (Table 4). The missing stages in the trials were because at that

time, we were constructing the scale and those developmental stages had not been

defined yet.

The time (in days) to each developmental stage varied with cultivar. For

instance, the marketable harvest time (stage R2) varied from 81 days for cultivar

Priscila to 97 days for cultivar Jester in the first trial (Table 2). Among planting dates,

for cultivar Jester the R2 was the shortest (95 days after planting) in the third trial

(Table 4) and the longest in the second trial (122 days after planting) (Table 3),

indicating strong effect of temperature on the rate of development.

Dry matter distribution among different plant parts (old corm, new corm, roots,

leaves and spike) changed with development stage (Figure 9). From emergence to

V3, about 80% of the plant dry matter is in the old corm and from V4 forward the

reserves in the old corm have all been used. Floret differentiation and spike growth

starts at V3, at V7 spike starts an intense linear growth and at VF (V8 in Figure 9)

leaf area is maximum. At R3-R4, spike dry matter is maximum and about 80% of the

total plant dry matter is in leaves and spike. Filiform roots are active until V4 and

concractile roots start to grow from that stage. Cormels usually start their growth at

R1 (it may vary among genotypes) and represent about 2% of the total plant dry

matter at R5. The new corm starts to grow at V1 but its growth is slow until R5. After

R5, the growth of the new corm increases because all photoassimilates produced by

leaves are translocated to below ground parts, until leaves senescence (R6).

3.5 Discussion

During the dormancy phase (S0, Figure 1A), the corm remains dormant due to

growth inhibitors, such as abscisic acid (ABA), as a strategy that allows the survival

of the structure in adverse field conditions, such as cold temperatures and low soil

moisture (Tombolato, 2004). The corm dormancy in gladiolus can be broken

artificially by cold storage (5C) or by applying growth regulators (Castro et al., 1970;

Vidalie, 1990).

40

The sprouting phase initiates when the corm is planted in the soil and roots

start to grow at the base of corm (S1, Figure 1B). Then sprouting takes place in the

upper part of the corm, and the root growth continues, concurrently with the sheaths

growth (insets of Figures 1D and 1E). It may be possible that some plants have a

fourth sheath and in this case the stage is coded as S2.4.

The vegetative phase contains a set of V-stages, starting at emergence (VE).

Note that at VE, only sheaths (incomplete leaves or bracts) are visible to the observer

(Figure 2A). Usually one or two bracts out of three, which work as protecting the first

true leaves that are growing inside the shoot whorl, turn out to be visible above soil

surface. Emergence is an important developmental stage in many phenological

systems (Zadoks et al., 1974; Fehr & Caviness, 1977; Counce et al., 2000), because

it represents the beginning of leaf area growth and therefore the beginning of solar

radiation interception by the canopy for photosynthesis.

During the vegetative phase, leaf area grows and intercepts solar radiation for

photosynthesis. Photoassimilates during the vegetative phase are used to grow

roots, the new corm and cormels, and the spike. An important field management

practice in gladiolus at the V3 stage is nitrogen side dressing because at floral

differentiation starts at this stage inside the whorl and is a strong nitrogen sink in the

plant (Shillo & Havely, 1976). When the last uppermost leaf tip (flag leaf) is visible

(Figure 2F), the final leaf number is defined, indicating that the vegetative phases has

ended.

The reproductive phase is composed of a set of R-stages, starting with R1.0

(Figure 3A). At this stage, it is important that plants are supported either with

individual stalks (wood or bamboo-made) or with a plastic net so that plants do not tilt

or lodge as the spike grows and becomes heavy. When gladiolus is part of a

composite in flowerbeds (Willery, 2010) lodging is usually not a problem as neighbour

plants work supporting gladiolus plant.

Following heading, the spike keeps growing in length. Florets grow from the

bottom upside within the spike (acropetal) and at some point in time the corolla of the

first florets shows the colour of the cultivar. In commercial plantations for cut flowers,

the R2 stage is the recommended harvest point for the spikes, giving them long life,

enough to be transported to the market and stay on the shelves, so that when

costumers see the spikes, these three florets are mostly open.

41

When the corolla of the first floret at the bottom of the spike is open, the stage

is named Onset of Anthesis (Figure 4B). In the Jester cultivars, the beautiful yellow

corolla is irregularly flamed with red, and is first visible at R3. When half of the florets

within the spike are open, the developmental stage is coded R 3.4 (Figure 5A).

Shortly after R3.5, usually the first floret at the bottom of the spike starts to senesce

(Figure 5B). Florets senescence occurs acropetaly from the bottom of the spike and

the R3.6 stage is reached when the floret located in the middle portion of the spike

starts senescence (Figure 5C). Anthesis and senescence of the florets proceeds

upwards within the spike until the last uppermost floret has its corolla open with

visible anthers (Figure 6A) and blooming ends. When the corolla of the uppermost

floret senesces (Figure 6B). After R5, the plant has green leaves, and

photoassimilates are translocated from the leaves to the new corm and cormels.

A gladiolus plant reaches the end of the cycle when the leaves have

completely died (leaves and floral axis are brown), coded R6 stage (Figure 7). At this

stage, translocation of assimilates to the new corm and the cormels ceases because

there are no more photosynthetically active organs. Thus, the maximum size of the

corm and the maximum number of cormels are set at R6.

The period from about R3 to R4 is the marketable life time of gladiolus as a cut

flower. The longer the R3-R4 period the better for costumers. Therefore, the search

for cultivars with longer R3-R4 period should be in the portfolio of desirable traits in

gladiolus breeding programs. The data on duration of R3 and R4 in Tables 2 to 4 are

based on gladiolus grown and left to flower in the field. As a cut flower, the spike is

removed from the plant and kept in vase from about R3 to R4, and florets open with

the reserves accumulated in the raquis before it was removed from the plant. Thus,

we expect a close relationship between the duration of the R3-R4 phase in the field

with its vase life, modulated by temperature.

The staging system proposed in Table 1 and illustrated in Figures 1 to 7 was

tested in the three field trails, where gladiolus plants of different cultivars grew in

distinct meteorological conditions. In the 2010 trial, vegetative development occurred

during mild temperatures in September and October (15 to 25C) while reproductive

development took place during warm temperatures (30 to 37C) in November and

December. In the 2011 trial, vegetative development occurred under mild

temperatures (20 to 25C) during the April, May and June, whereas reproductive

development occured under low temperatures (5 to 15C), during July and August. In

42

the third trial, the vegetative development occurred from August to October, when

temperatures were mild (15 to 25C) and reproductive development occurred in

November (25-30C), except the period between R5 and R6, which occurred from

December to March, under elevated temperatures (25-35 C). These trials provided a

good data set to evaluate the criteria for identifying each developmental stage of the

proposed staging system.

In our team we had a total of six personnel that went to the field and made the

observations of the developmental stages in the trials. In each visit to the plants, at

least two persons looked at the plants and independently evaluated the criteria.

Overall, the personnel graded the criteria as being easy and fast for all

developmental stages. These results are important, as detailed experiments where

several developmental stages have to be analysed can be very time-consuming and

labor-demanding. Another important feature in a developmental scale is if the criteria

are clear and objective. The personnel who did the observations unanimously agreed

about clearness and objectiveness of the descriptions provided in Table 1, rendering

consistency among observations made by different people.

The different planting dates in the three trials resulted in different durations of

vegetative and reproductive stages (Tables 2, 3 and 4). The average duration was 62

days, 77 days and 64 days for the vegetative (VE-VF) phase and 23 days, 40 days

and 22 days for the reproductive phase (R1-R5) in the trials planted on 08/09/2010,

30/03/2011 and 05/08/2011, respectively. The longest duration of all developmental

stages in the 30/03/2011 planting date compared to the other two planting dates is

because plants in the former planting date development during Autumn and Winter

(from April to August) when the air temperature varied from -1.1C to 31.7C whereas

plants in the other two planting dates developed during the warmest months (from

September to March) when air temperature varied from 1.2C to 36.3C. These

results indicate that air temperature has an important effect on the rate of the

development in gladiolus, as in other agricultural crops (Hodges, 1991; Wilhelm &

McMaster, 1995; Streck et al., 2003).

The phyllochron, which can be defined as the difference between successive

V-stages, varied from 1 to 13 days per leaf (Table 4), with greater values for the first

four leaves (V1 to V4) and smaller values for later leaves (V5 to V8). This difference

in the rate of leaf appearance is related to temperature, as the first four leaves

developed from 30/08/2011 to 01/10/2011 when mean air temperature was 16.3C

43

whereas the last four leaves developed from 07/10/2011 to 29/10/2011, when mean

air temperature was 19.6C. This effect of temperature on leaf appearance rate has

also been reported for other agricultural crops (Wilhelm and McMaster, 1995; Streck

et al., 2003).

Plant growth (dry matter accumulation and its partitioning among plant parts)

is modulated by developmental stages (Figure 9). As plant development progresses,

some growth processes are switched on or switched off at specific developmental

stages. For instance, in gladiolus during the vegetative phase, the majority of plant

dry matter accumulates in the leaves, at the V3-stage the spike starts its growth and

at the V4-stage the contractile roots starts their growth, whereas cormels only starts

their growth at R1 (Figure 9). This dynamic relationship between growth and

development is another example on how important is a detailed phenological scale

for gladiolus. We expect the dry matter partitioning pattern in Jester presented in

Figure 9 also works for other commercial gladiolus cultivars, which only small

variations related to the number of cormels and leaves per plant, which are genotype-

dependent traits.

The development scale proposed in this paper is an easy and practical field

scale, suitable for use by farmers and extensionists, and for research purpose in

experimental trials. The scale was tested with seven commercial gladiolus cultivars

(Table 2, 3 and 4) that are widely grown in Brazil and that have the same colours and

morphological features as gladiolus cultivars grown in Europe and North America.

Consequently, the developmental scale (Table 1) works for commercial cultivars of

gladiolus (Gladiolus x grandiflorus Hort.). The scale comprises stages during different

developmental phases, from sprouting, vegetative and reproductive phases,

including the period of commercial interest to producers of cut flowers (VE to R2) and

extends to plant senescence (R6), based on discrete (dichotomously) naked-eye

morphological criteria. The vegetative development is based on CLN and the system

can be expanded to include the development of the spike inside the whorl before its

appearance (R1). Floret differentiation (which occurs at V3, Figure 2D) is coded as

R0 so that early reproductive development (R0-R1) overlaps part of the vegetative

development (V3-VF). The partial overlapping between vegetative and reproductive

development also happens in other agricultural crops such as wheat (Zadoks et al.,

1974), soybean (Fehr & Caviness, 1977) and rice (Counce et al., 2000).

44

3.6 References

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the growth of gladiolus corm in Peshawar. Sarhad Journal of Agriculture, 27, 195-

199.

CASTRO P.R.C.; MINAMI K.; GIL C.M.; DEMTRIO C.G.B. (1970) Efeitos da

vernalizao e de fitoreguladores no desenvolvimento de Gladiolus grandiflorus.

Anais da E.S.A Luis de Queiros, 36, 153-171.

COUNCE P.A.; KEISLING T. C.; MITCHELL M.J. (2000) A uniform, objetive, and

adaptative system for expressing rice development, Crop Science, 40, 436-443.

CUEVAS R.H. (1999) Produccin de Gladiolo. Instituto de Investigaciones

Agropecuarias - Centro Regional de Investigacion Carillanca.

DELGADO P.M.H.; ARANGUREN M.; REIG C.; GALVN D.F.; MESEJO C.;

FUENTES A.M.; SACO V.G.; AUGUST M. (2011) Phenological growth stages of

mango (Mangifera indica L.) according to the BBCH scale, Scientia Horticulturae,

130, 536-540.

FEHR W.R.; CAVINESS C.E. (1977) Stages of soybean development, Ames: Iowa

State University of Science and Technology (Special Report, 80).

FELLER C.; BLEIHOLDER H.; BUHR L.; HACK H.; HESS M.; KLOSE R.; MEIER U.;

STAUSS R.; VAN DEN BOOM T.; WEBER E. (1995) Phnologische

Entwicklungsstadien von Gemsepflanzen: I. Zwiebel-, Wurzel-, Knollen- und

Blattgemse. Nachrichtenbl. Deut. Pflanzenschutzd, 47, 193206.

GARCIA-CARBONELL S.; YAGE B.; BLEIHOLDER H.; MEIER U.; AUGUSTI M.

(2002) Phenological growth stages of the persimmon tree (Diospyros kaki). Annals

of applied Biology, 141, 73-76.

45

GONALVES C.; JNIOR M.J.P.; CASTRO C.E.F. (2008) Fenologia e estimativa da

durao do ciclo da znia 'Profusion Cherry' cultivada em vasos em ambiente

protegido. Bragantia, 67, 527-532.

GREVING A.J. (1987) Historical Materials from University of Nebraska-Lincoln

Extension: G87-852 Growing Gladiolus, University of Nebraska.

HANWAY J.J. (1966) Growth stages of corn (Zea mays L.). Agronomy Journal, 55,

487-492.

HAUN J.R. (1973) Visual quantification of wheat development. Agronomy Journal,

65, 116-119.

HODGES T. (1991) Introduction. In: Hodges T. (Ed.) Predicting Crop Phenology.

Boston: CRC 1-2.

LARGE E.C. (1954) Growth stages in cereal - Ilustration of the Feekes scale. Plant

Pathology 3: 128-129.

MEIER U.; BLEIHOLDER H.; BUHR L.; FELLER C.; HACK H.; HEB H.;

LANCASHIRE P.D.; SCHNOCK U.; STAUB R.; VAN DEN BOOM T.; WEBER E.;

ZWERGER P. (2009b) The BBCH system to coding the phenological growth stages

of plants history and publications. Journal FrKulturpflanzen, 61, 4152.

MEIER U.; BLEIHOLDER H.; BRUMME H.; BRUNS E.; MEHRING B.; PROLL T.;

WIEGAND J. (2009a) Phenological growth stages of roses (Rosa sp.): codification

and description according to the BBCH scale. Annals of Applied Biology, 154 (2),

231-238.

MORAIS H.; CARAMORI P.H.; KOGUISHI M.S.; RIBEIRO A.M.A. (2008) Escala

fenolgica detalhada da fase reprodutiva de Coffea arabica. Bragantia, 67, 257-260.

46

RIAZ T.; KHAN S.N.; JAVAID A. (2010) Management of Fusarium corm rot of

gladiolus (Gladiolus grandiflorus sect. Blandus cv. Aarti) by using leaves of

allelopathic plants. African Journal of Biotechnology, 9, 4681-4686.

RITCHIE S.W.; HANWAY J.J.; BENSON G.O. (1993) How a corn plant develops.

Ames: Iowa State University of Science and Technology, Cooperative Extension

Service (Special Report, 48).

SNZ-CORTS F.; MARTNEZ-CALVO J.; BADENES M.L.; BLEIHOLDER H.;

HACK H.; LLCER G.; MEIER U. (2002) Phenological growth stages of olives trees

(Olea europaea). Annals of applied Biology, 140: 151-157.

SHILLO R.; HALEVY A.H. (1976) Inflorescence development of flowering and blasted

gladiolus plants in relation to development of other plant parts. Scientia

Horticulturae 4: 79-86.

SMITH R.C. (2006) Giddy over Gladiolus. North Dakota State University, Fargo,

North Dakota.

STRECK N.A.; WEISS A.; XUE Q.; BAEZINGER P.S. (2003) Incorporating a

chronology response function into the prediction of leaf appearance rate in winter

wheat. Annals of Botany, 92, 181-190.

TOMBOLATO A.F.C.; CASTRO J.L.; MATTHES L.A.F.; LEME J.M. (2005)

Melhoramento gentico do gladolo no IAC: novos cultivares IAC Carmim e IAC

Paranapanema. Cientfica, 33, 142-147.

TOMBOLATO A.F.C. (2004) Cultivo comercial de plantas ornamentais. Campinas:

Instituto Agronmico de Campinas (IAC).

TRINKLEIN D. (2005) G6620 Summer Flowering Bulbs: Gladiolus. Missouri:

University of Missouri.

47

VIDALIE H. (1990) Les productions florales (Collection Agriculture dAujourdhui).

Paris: ditions Tec Et Doc / Lavoisier.

WILHELM W.W.; MCMASTER G.S. (1995) Importance of the phyllochron is studying

development and growth in grasses. Crop Science, 35, 1-3.

WILLERY D. (2010) The garden of Claude Monet. Paris: Ulmer.

ZADOKS J.C.; CHANG, T.T.; KONZAK C.F. (1974) A decimal code for the growth

stages of cereals. Weed Research, 14, 415-421.

48

Table 1. The developmental staging system for gladiolus.

Phase Stages Code Description

Dorm

ancy

Dormant corm S0 Buds and root nodules are at a rest and covered by the husks that overlap each other covering the corm and meeting at the

top of the corm.

Spro

utin

g

Appearance of roots

S1 Roots start growing from root nodules at the base of the corm.

First sheath S2.1 The first sheath that grew from the apex is visible at the top of

the corm pushing up the husks.

Second sheath S2.2 Sheaths continue its growth through the husks and the second

sheath is visible at the top of the corm. Third sheath S2.3 Third sheath is visible at the top of the corm.

Veg

eta

tive

Emergence VE Shoot is first visible above the ground.

First Leaf V1 First true leaf tip is visible at the shoot whorl.

Second Leaf V2 Second true leaf tip is visible at the shoot whorl.

Third Leaf V3 Third true leaf tip is visible at the shoot whorl. Floret

differentiation starts at the apex (R0).

Nth Leaf Vn n

th true leaf tip is visible at the shoot whorl.

Flag Leaf VF Last leaf tip is visible at the shoot whorl.

Repro

dutive

Heading

R1.0 Spike tip first visible at the shoot whorl.

R1.1 Half of the spike emerged. The tip of the spike is levelled with

the high of the tip of the last leaf.

R1.2 Emergence of spike completed. The peduncle of the spike is visible. After R2 the rachis elongates and florets grow apart.

Blooming R2 First three florets at the bottom of the spike show the colour of

the corolla. This is the marketable harvest point.

Onset of Anthesis R3 The corolla of the first floret at the bottom on the spike is open

with visible anthers.

Half of Anthesis R3.4 The corolla of the floret located at the middle portion of the

spike is open with visible anthers. Beginning florets

senescence R3.5

First floret at the bottom of the spike starts senescence (corolla of the first floret is dehydrated).

Half florets senesced

R3.6 Floret at the middle of the spike starts senescence

Anthesis completed

R4 The corolla of the last uppermost floret on the spike is open with

visible anthers. End of florets senescence

R5 Last uppermost floret on the spike senesced. Corolla of all

florets are dead.

Plant senescence R6 Above ground parts of the plant (leaves and floral axis) are

brown (dead plant).

49

Table 2. Number of days from planting to developmental stages (DS) in seven

gladiolus cultivars planted on 08 Sep. 2010, at Santa Maria, RS, Brazil.

DSa

Cultivars

Priscila Peter Pears

Trader Horn

Sunset Rose Supreme

T704 Jester

VE 20 30 29 28 21 27 32

VFb 81 86 95 86 90 91 91

R1.0 72 78 83 82 87 85 88

R2 81 87 92 91 96 94 97

R3 85 89 95 91 98 96 100

R4 93 102 107 105 111 106 109 a For description of developmental stages (DS) see Table 1. b Priscila and Peter Pears cultivars had eight leaves and the other cultivars had nine leaves.

Table 3. Number of days from planting to several developmental stages in three

gladiolus cultivars planted on 30 Mar. 2011, at Santa Maria, RS, Brazil.

Developmental Stagesa

Cultivars

Jester Trader Horn T704

VE 24 19 21 VFb 115 100 79 R1.0 110 91 100 R2 130 109 122 R3 132 114 126

R3.5 139 122 128 R4 148 131 143

a For description of developmental stages see Table 1. b Cultivar T704 had eight leaves and the other cultivars had nine leaves.

50

Table 4. Number of days from planting to several developmental of developmental

stages in three gladiolus cultivars planted on 05 Aug. 2011, at Santa Maria, RS,

Brazil.

Developmental Stagesa

Cultivars

Peter Pears T704 Jester

VE 23 26 22 V1 25 29 28 V2 35 42 41 V3 46 49 51 V4 54 59 57 V5 63 68 67 V6 69 72 74 V7 77 77 75 V8 82 85 80 V9 87 -b 87 VF 83 89 91

R1.0 85 87 85 R1.1 86 87 88 R1.2 87 90 88 R2 95 93 95 R3 97 98 99

R3.4 100 99 101 R3.5 99 99 102 R4 106 108 110 R5 109 109 112 R6 217 185 215

a For description of Developmental stages see Table 1. b Cultivar T704 had nine leaves.

51

Figure 1. Developmental stages during the Dormancy and Sprouting phases in gladiolus: S0 = Dormant corm (A), S1 = appearance of roots nodules at the base of the corm (B),S2.1 = first shealth (C), S2.2 = second shealth (D), S2.3 = third shealth (E). The arrow in the insets of panels D and E indicates the filiform roots at the base of the corm.

52

Figure 2. Developmental stages during the vegetative phase of gladiolus: VE = emergence (A), V1 = first leaf (B), V2 = second leaf (C), V3 = third leaf (D) (the detail in V3 is the floret differentiation R0), V6 = sixth leaf (E), and VF = flag leaf (F).

Figure 3. Development of the spike during the reproductive phase in gladiolus: R1.0 = spike first visible at the whorl (A), R1.1 = half of the spike emerged from whorl (B), R1.2 = emergence of spike is completed (C).

53

Figure 4. Development of the spike during the reproductive phase in gladiolus: R2 = first three florets at the bottom of the spike show the colour of the corolla (A), R3 = the corolla of the first floret at the bottom of the spike is open with visible anthers (B).

Figure 5. Development of the spike during the reproductive phase in gladiolus: R3.4 = the corolla of the floret located at the middle portion of the spike is open with visible anthers (A), R3.5 = first floret at the bottom of the spike starts senescence (B), R3.6 = floret at the middle of the spike starts senescence (C).

54

Figure 6. Development of the spike during the reproductive phase in gladiolus: R4 = the corolla of the last uppermost floret on the spike is open with visible anthers (A), R5 = last uppermost floret on the spike senesced (B).

Figure 7. Development of the spike during the reproductive phase in gladiolus: R6 = above ground parts of the plant is senesced (dead plant).

55

Figure 8. Developmental sequence in gladiolus. For description of developmental stages see Table 1. The detail in V3 is the floret initiation at the apex (R0), which is only possible to be seen under 14 x magnification.

Figure 9. Dry matter distribution among different parts of a gladiolus plant (cv. Jester) as a function of developmental stage and days after emergence (DAE). Planting dates was on 14 Sep. 2012. Each point is the mean of five plants.

4 CAPTULO II DIMENSES LINEARES DA FOLHA E SEU USO NA

DETERMINAO DO PERFIL VERTICAL FOLIAR DE GLADOLO

Artigo submetido revista Bragantia em 03/03/2014.

Situao atual: aceito para a publicao no v.73, n.2, 2014.

4.1 Resumo

O gladolo, importante flor de corte, uma planta herbcea e suas folhas

apresentam forma lanceolada. O trabalho foi conduzido com o objetivo de determinar

um modelo matemtico emprico que melhor estime a rea da folha do gladolo a

partir de dimenses lineares e aplicar o modelo matemtico para determinar o perfil

vertical da rea das folhas de diferentes posies na planta. Para isso, foi realizado

um experimento de campo em Santa Maria/RS, com quatro cultivares de gladolo

(Peter Pears, Rose Friendship, Jester e Amsterd), sendo coletadas cinquenta

folhas de cada cultivar, e mensurou-se o comprimento (C) e a maior largura (L) de

cada folha. Em seguida, fotocopiou-se cada folha em um scanner, calculando-se a

rea individual (AF) com auxlio de um software. A relao entre rea e as

dimenses das folhas foi ajustada no modelo potncia e a capacidade preditiva das

equaes foi avaliada por vrias estatsticas. Resultados indicam que o modelo AF=

a (C.L) o mais indicado para a estimativa da rea foliar em gladolo, podendo-se

utilizar a = 0,644 para as quatro cultivares testadas. As menores folhas esto nas

posies basais e apicais e as maiores folhas na posio intermediria da planta.

Palavras-chave: Gladiolus x grandiflorus Hort., Palma-de-Santa-Rita, floricultura,

rea fotossintetizante.

58

4.2 Introduo

O gladolo ou palma-de-Santa-Rita (Gladiolus x grandiflorus Hort.) uma

importante flor de corte (Choudhar et al., 2011) cultivada na maioria dos pases

tropicais e subtropicais (Ahmad et al., 2011). Ocupa a oitava posio mundial no

comrcio de flores de corte (Ahmad et al., 2008) e no Brasil tem maior consumo em

Finados. uma planta herbcea, perene de ciclo anual, propagada por cormos e

com folhas simples de forma lanceolada.

Semelhante outras culturas agrcolas, estudos bsicos do crescimento e

desenvolvimento vegetal em espcies florcolas so importantes, pois tais estudos

explicam o rendimento final da cultura e auxiliam no refinamento de prticas de

manejo para maximizar a eficincia de ecossistemas com o mnimo de impacto

ambiental. Dentre os parmetros de crescimento vegetal, a rea das folhas

representa um dos mais importantes, pois est relacionada interceptao da

radiao solar, a qual responsvel pela produo de fotoassimilados, que

implicaro diretamente na produtividade biolgica e econmica da cultura. O ndice

de rea foliar (IAF) um dos ndices ecofisiolgicos mais utilizados em estudos da

dinmica do crescimento e desenvolvimento de folhas e representa a rea total das

folhas pela rea de solo que cada planta ocupa na lavoura. No entanto, nem todas

as folhas que compem o IAF esto diretamente expostas radiao solar, pois

existe um perfil vertical de distribuio da rea das folhas, que varia com sua

posio na haste (Fagundes et al., 2009). Em gladolo, a insero das folhas a

partir de pontos muito prximos, que saem de um caule subterrneo expandido,

denominado cormo.

A rea foliar de uma planta depende do nmero e do tamanho das folhas e

pode ser determinada a partir de mtodos de medio destrutivos (diretos) ou no

destrutivos (indiretos) (Marshall, 1968), tais como o uso de aparelho integrador de

rea foliar, para o primeiro caso, e a partir de medidas lineares do limbo, no caso de

mtodo indireto (Aquino et al., 2011). Os mtodos destrutivos tm a desvantagem de

no serem aplicveis em casos onde a quantidade de amostras limitada e/ou

quando se pretende manter a avaliao de outros parmetros em experimentos por

um longo perodo de tempo, o que impossibilita a destruio das unidades

experimentais ou parcelas para realizao de medidas diretas da rea foliar. J com

59

os mtodos no destrutivos (indiretos) as plantas amostradas so mantidas na

parcela e assim pode-se acompanhar o crescimento e a expanso das folhas de

uma mesma planta at o final do seu ciclo (Fagundes et al., 2009).

O mtodo indireto de determinao da rea de folhas a partir de dimenses

lineares j foi utilizado para diversas culturas agrcolas, tais como girassol (Aquino et

al., 2011), batata (Silva et al., 2008), feijo-caupi (Lima et al., 2008), feijo-vagem

(Toebe et al., 2012), couve-folha (Marcolini et al., 2005) e tambm para plantas

invasoras, como por exemplo Brachiaria plantaginea (Bianco et al., 2005), Brachiaria

subquadripara, Brachiaria mutica (Marchi et al., 2011) e Typha latifolia (Bianco et al.,

2003). Como neste mtodo usa-se modelos ajustados por regresso, os coeficientes

so dependentes da espcie e at da cultivar dentro de cada espcie devendo-se,

portanto, determin-los para cada gentipo. Em gladolo, no foi encontrada na

literatura relato sobre a estimativa da rea das folhas a partir de dimenses lineares,

o que constituiu motivao para a realizao deste trabalho.

Os objetivos do trabalho foram: a) determinar um modelo matemtico

emprico que melhor estima a rea da folha do gladolo a partir de dimenses

lineares e b) aplicar o modelo matemtico para determinar o perfil vertical da rea

das folhas em diferentes posies na planta.

4.3 Material e mtodos

Um experimento de campo com a cultura do gladolo foi conduzido em Santa

Maria (RS) (altitude local de 95 m, latitude 29 43 23 e longitude 53 43 15).

Foram realizados plantios em quatro datas, 18/4/2012, 19/7/2012, 14/9/2012 e

17/7/2013, com as cultivares Peter Pears (ciclo precoce), Rose Friendship (ciclo

mdio) e Jester (ciclo tardio) para as duas primeiras datas de plantio, Amsterd

(ciclo precoce), Rose Friendship e Jester, para a terceira data de plantio e Peter

Pears (ciclo precoce) para a quarta data de plantio. A adubao foi de 500 kg ha-1 de

NPK 5-20-20, seguindo a anlise de solo (Apndice H).

As plantas foram cultivadas em canteiros com 1 m de largura, distribudas em

linhas pareadas espaadas em 0,40 m e espaamento entre plantas de 0,20 m.

60

Foram realizados tratos culturais indicados para a espcie durante o ciclo de

desenvolvimento (Tombolato, 2004).

Para a estimativa das equaes que relacionam a rea de folhas individuais

com duas dimenses lineares, coletaram-se cinquenta folhas de plantas sadias de

cada cultivar na primeira data de plantio (Peter Pears, Rose Friendship e Jester) e

mais cinquenta folhas na terceira data de plantio (Amsterd), de diversos tamanhos

e posies na planta, nos mais variados estgios de desenvolvimento. Tomou-se o

cuidado de destacar as folhas na sua insero, de modo que somente a poro

fotossinteticamente ativa da folha fosse amostrada.

Aps o destacamento, foi medido o comprimento (C) e a maior largura (L) de

cada folha (Figura 1). O comprimento foi definido como a distncia entre o ponto de

insero da folha no limbo da folha antecedente e a extremidade oposta e a largura

como a maior dimenso perpendicular ao eixo do comprimento. Em seguida, cada

folha foi fotocopiada em um scanner e a rea ind