Discerning the Response of Rice (Oryza sativa L.) Cultivars to Salinity underContrasting Moisture Regimes

摘要

Rice is an important cereal grown under different cultivation systems. The impact of different cultivation system on salinity is a concern. A study using six genotypes (having varied level of salt tolerance) with five saline treatments under aerobic and wetland conditions imposed at reproductive stage showed different behavior for different genotypes. Salinity tolerance at cellular level was understood by quantifying apoplastic, intracellular sodium (Na+) and potassium (K+). Pokkali varieties exhibited lower Na+ in the apoplastic space reflecting their saline tolerance character. ARB6 recorded higher apoplastic Na+, indicating a possible trade-off between drought resistance (aerobic condition) and saline tolerance. Same trend was also seen in intracellular Na . There was no significant difference for K~+/ Na~+ ratio between aerobic and wetland conditions. T test indicated the significant difference for apoplastic Na~+ accumulation and intracellular K~+ accumulation between two cultivation systems of rice. Tiller number and root volume manifested significant difference between two conditions studied. Salt accumulation under aerobic condition was significantly higher than wetland conditions in all varieties, indicating different mechanism of salinetolerance among cultivation systems.