Environmental effects on photosynthetic capacity of bean genotypes

Pesquisa Agropecuária Brasileira

Rafael Vasconcelos Ribeiro²  Mauro Guida Dos Santos²  Gustavo Maia Souza²  Eduardo Caruso Machado¹  Ricardo Ferraz De Oliveira²  Luiz Roberto Angelocci¹  Carlos Pimentel¹ 

[1] ,Escola Superior de Agricultura Luiz de Queiroz Dep. de Ciências Biológicas Piracicaba SP ,Brazil

关键词: Phaseolus vulgaris;    chlorophyll fluorescence;    gas exchange;    photosynthesis;    Phaseolus vulgaris;    fluorescência de clorofila;    fotossíntese;    trocas gasosas;   

DOI  :  10.1590/S0100-204X2004000700001

来源: SciELO

【 摘 要 】

Photosynthetic responses to daily environmental changes were studied in bean (Phaseolus vulgaris L.) genotypes 'Carioca', 'Ouro Negro', and Guarumbé. Light response curves of CO2 assimilation and stomatal conductance (g s) were also evaluated under controlled (optimum) environmental condition. Under this condition, CO2 assimilation of 'Carioca' was not saturated at 2,000 µmol m-2 s-1, whereas Guarumbé and 'Ouro Negro' exhibited different levels of light saturation. All genotypes showed dynamic photoinhibition and reversible increase in the minimum chlorophyll fluorescence yield under natural condition, as well as lower photosynthetic capacity when compared with optimum environmental condition. Since differences in g s were not observed between natural and controlled conditions for Guarumbé and 'Ouro Negro', the lower photosynthetic capacity of these genotypes under natural condition seems to be caused by high temperature effects on biochemical reactions, as suggested by increased alternative electron sinks. The highest g s values of 'Carioca' were observed at controlled condition, providing evidences that reduction of photosynthetic capacity at natural condition was due to low g s in addition to the high temperature effects on the photosynthetic apparatus. 'Carioca' exhibited the highest photosynthetic rates under optimum environmental condition, and was more affected by daily changes of air temperature and leaf-to-air vapor pressure difference.

【 授权许可】

CC BY   
 All the contents of this journal, except where otherwise noted, is licensed under a Creative Commons Attribution License