Portal de Periódicos da CAPES

Artigo Acesso aberto Produção Nacional Revisado por pares

BIBTEX RIS

Photosynthetic parameters and leaf water potential of five common bean genotypes under mild water deficit

2009; Institute of Experimental Botany of the Czech Academy of Sciences; Volume: 53; Issue: 2 Linguagem: Inglês

10.1007/s10535-009-0044-9

1573-8264

Mauro G. Santos, Rafael Vasconcelos Ribeiro, Eduardo Caruso Machado, Carlos Pimentel,

Plant responses to elevated CO2

The leaf water potential, gas exchange and chlorophyll fluorescence were evaluated in five common bean (Phaseolus vulgaris) genotypes A222, A320, BAT477, Carioca and Ouro Negro subjected to moderate water deficit. At the maximum water deficit (10 d of water withholding), the leaf water potential of genotypes A320 and A222 was higher (-0.35 and -0.50 MPa) when compared to the other genotypes (-0.67 to -0.77 MPa). The stomatal conductance and net photosynthetic rate were significantly reduced in all genotypes due to the water deficit. The greater reduction in stomatal conductance of A320 under drought resulted in high intrinsic water use efficiency. Mild water deficit affected the photochemical apparatus in bean genotypes probably by down-regulation since plants did not show photoinhibition. The photochemical apparatus of A222 and A320 genotypes was more sensitive to drought stress, showing reduced apparent electron transport even after the recovery of plant water status. On the other hand, even after 10 d of water withholding, the maximum efficiency of photosystem 2 was not affected, what suggest efficiency of the photoprotection mechanisms.