Salinity and drought induced changes in gas exchange attributes and chlorophyll fluorescence characteristics of rice (Oryza sativa) varieties

摘要

The present study was conducted to assess the effect of water deficit coupled with salt stress on physiological traits and stress tolerance mechanisms of rice (Oryza sativa L.) varieties differing in salt tolerance. Two salt tolerant (CSR 10 and CSR 36) and two salt sensitive (IR 29 and Pusa 44) rice varieties were evaluated in different combinations of controlled water deficit coupled with salt stress conditions. The salt tolerant variety CSR 10 has shown the best morphological or phenological growth performance; while IR. 29 performed the worst in terms of reduction in growth at 25 and 50% water deficit. At 50 and 100 mM NaCl along with 50% water deficit, 80% plants of IR 29 could not survive. Variety CSR 10 exhibited maintenance of higher total chlorophyll concentration (Chl(T)), relative water content (RWC), gas exchange characteristics and chlorophyll fluorescence attributes with lower membrane injury (MI) and thus ultimately showed better stress tolerance than other varieties.