Trocas gasosas e eficiência fotoquímica de cultivares de algodoeiro herbáceo sob aplicação de silício foliar
Carregando...
Arquivos
Data
2014-01-01
Autores
Souza Ferraz, Rener Luciano de [UNESP]
Macedo Beltrao, Napoleao Esberard de
Melo, Alberto Soares de [UNESP]
Magalhaes, Ivomberg Dourado
Fernandes, Pedro Dantas
Rocha, Maria do Socorro
Título da Revista
ISSN da Revista
Título de Volume
Editor
Univ Estadual Londrina
Resumo
The objective of this study was to evaluate gas exchange and photochemical efficiency of cotton cultivars under leaf application of silicon. Therefore, the experiment was conducted in a completely randomized in a factorial 3 x 5, three cotton cultivars ('BRS Topazio', 'BRS Safira' and 'BRS Rubi'), five silicon concentrations (0, 50, 100, 150, 200 mg L-1) and four replications. Gas exchange and photochemical efficiency were determined by measuring the rate of CO2 assimilation, transpiration, stomatal conductance, internal CO2 concentration, instantaneous efficiency in water use, instantaneous carboxylation efficiency, initial fluorescence, maximum quantum efficiency of the variable and photosystem II (PSII). The data variables were subjected to analysis of variance and regression test comparison of means. There were significant differences in gas exchange and photochemical efficiency in response to concentrations of silicon. There were also significant differences among cotton cultivars evaluated. In cultivar 'BRS Top zio', the application of silicon increased CO2 assimilation rate and quantum efficiency of PSII. In 'BRS Safira' silicon reduced the rate of assimilation and internal CO2 concentration. In 'BRS Rubi' element increased the fluorescence of chlorophyll 'a' and quantum efficiency of photosystem II, and reduced the rate of assimilation and internal CO2 concentration and stomatal conductance. Silicate fertilization provided 'BRS Topazio' to express better photosynthetic rate in relation to 'BRS Safira' and 'BRS Rubi'. No damage occurred in PSII when 'BRS Top zio', 'BRS Safira' and 'BRS Rubi' cultivars received silicon as supplementary nutrition.
Descrição
Palavras-chave
Gossypium hirsutum L., leaf nutrition, photosynthesis, potassium silicate
Como citar
Semina-ciencias Agrarias. Londrina: Univ Estadual Londrina, v. 35, n. 2, p. 735-748, 2014.