Data/hora: 09/06/2024 15:51:15

Provedor de dados: | 63
País: | Brazil
Título: | Salt stress induced damages on the photosynthesis of physic nut young plants
Autores: | Silva,Evandro Nascimento da; Ribeiro,Rafael Vasconcelos; Ferreira-Silva,Sérgio Luiz; Viégas,Ricardo Almeida; Silveira,Joaquim Albenisio Gomes.
Data: | 2011-02-01
Ano: | 2011
Palavras-chave: | Jatropha curcas; Chlorophyll fluorescence; Gas exchange; Ionic toxicity; Salinity.
Resumo: | Salinity is a major limiting factor to crop productivity in the world especially in semiarid regions. The aim of this study was to evaluate the photosynthetic resistance of Jatropha curcas (L.) young plants subjected to salt stress. The experiment was carried out in a completely randomized design with treatments in a 2 x 3 factorial: two NaCl levels (0 and 100 mmol L-1) and three harvest times: 7 and 14 days of salt exposure and three days of recovery. Leaf Na+ and Cl-concentrations and the K+/Na+ ratios, after seven days of salt exposure, did not reach ionic toxic levels, suggesting that the NaCl-induced osmotic effects prevailed over the ionic ones. Under this condition, the salt stress caused reduction in leaf gas exchange parameters, such as CO2 fixation, stomatal conductance and transpiration. In contrast, salt stress did not change the photochemical efficiency of photossystem II. Conversely, after 14 days of treatment, Na+ and Clions reached very high concentrations, up to toxic levels in leaves. Under such conditions, both leaf gas exchange and photochemistry suffered strong impairment probably caused by ionic toxicity. The recovery treatment for 3d did not significantly decrease the leaf salt concentrations and no improvement was observed in the photosynthetic performance. Physic nut young plants are sensitive to high NaCl-salinity conditions, with high leaf Na+ and Cl- concentrations, low K+/Na+ ratio and great photosynthetic damages due to stomatal and biochemical limitations.
Tipo: | Info:eu-repo/semantics/article
Idioma: | Inglês
Identificador: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162011000100010
Editor: | São Paulo - Escola Superior de Agricultura "Luiz de Queiroz"
Relação: | 10.1590/S0103-90162011000100010
Formato: | text/html
Fonte: | Scientia Agricola  v.68 n.1 2011
Fonte: | info:eu-repo/semantics/openAccess