EFFECT OF TRANSPIRATION RATE ON SODIUM ACCUMULATION IN RICE (ORYZA SATIVA L.) GROWN UNDER SALINE CONDITIONS

Uptake and transporting pattern of toxic ions to the shoot is a crucial response by plant under saline conditions affecting metabolic activities and thereby determines salt sensitivity/tolerance in rice. Experiments were conducted to compare the rate of transpiration and its effect on sodium accumulation in shoot of two inbred rice lines (IR55178 - 163 tolerant and IR55178 - 104 sensitive differing in salt tolerance along with a salt tolerant check Shua-92) under different levels of salinity (0, 50 and 75 mM). The parameters studied indicated that transpiration rates were sharply decreased in response to salinity in both genotypes. While, sodium uptake continued to increase however, the tolerant genotype maintained transpiration rate quite satisfactorily and also exhibited ability to maintain higher K: Na ratio and low Na concentration in the xylem than the sensitive genotype. It is concluded that transport of sodium ions in the present study was negatively correlated with transpiration (r = -0.806).