Saline (NaCl) stress in germinated seedlings of rice cv. Rupsail causes an increase in polyamine content and concomitantly an enhancement of arginine decarboxylase (ADC) activity; in the case of putrescine, the increase is 100%. The responsiveness of coleoptiles and roots is different; ADC activity is maximum in roots and coleoptiles at 50 mM and 100 mM respectively. Difluoromethyl arginine, a potent inhibitor of ADC, reduces both polyamine accumulation and ADC activity. NaCl can enhance the activity of ADC by 1.6-fold in vitro. [14C]leucine incorporation into protein at 400 mM NaCl is decreased 4- and 10-fold in coleoptiles and roots, respectively. Efflux of sugar, amino acid, polyamines and total electrolytes increased gradually with the increase in concentration of salt. Influx of Na+ and Cl- and efflux of K+ in coleoptiles and roots are directly proportional to the concentration of NaCl applied.
K+ Efflux and Retention in Response to NaCl Stress Do Not Predict Salt Tolerance in Contrasting Genotypes of Rice (Oryza sativa L.)
