AMELIORATION OF SALINITY EFFECT IN SALT TOLERANT RICE (ORYZA-SATIVA L) BY FOLIAR APPLICATION OF PUTRESCINE

Amelioration of NaCl (electric conductivity 15 mmho cm-1) toxicity in the salt tolerant rice cultivar Co 43 was investigated on 25th and 45th day old plants by foliar application of diamine putrescine (10-mu-M) in a pot culture experiment. Exogenous supply of putrescine on salt stressed plants considerably increased the shoot growth (fresh weight and dry weight) and grain yield. Foliar application of putrescine inhibited the Na+ and Cl- uptake, and accelerated the accumulation of K+, Ca2+, Mg2+, proline and endogenous putrescine in the leaves of salt-stressed plants. Furthermore, putrescine application prevented degradation of chlorophyll and inhibited the reductions of soluble protein, total protein, RNA and DNA contents, and elevated their concentrations in the leaves of plants exposed to salinization. The physiological role of putrescine in several stress-related processes is discussed with salt tolerance of plants.