Effects of Drought-induced and Salinity-induced Water Deficition on Some Physiological Characteristice and Carbohydrate Metabolism in Rice Seedlings (Oryza sativa L)(Thai)

Abstract

Effects of drought-induced and salinity-induced water deficit stresses on some physiological characteristics and carbohydrate metabolism were investigated in rice seedlings (Oryza sativa L. cv. Khao Dawk Mali 105). Rice seedlings were germinated and grown in MS medium. Drought was induced by adding sorbitol to the culture medium at concentrations of 0, 50, 100, 150 and 200 mM, while salinity was induced by adding sodium chloride to the medium at the same concentration. Rice seedlings were grown for 15 days. The result showed that rice grown under drought had increased root length whereas those grown under salinity had shorter roots. Both had decreased shoot length compared to the control group. Rice grown under drought had longer roots and shoots than those grown under salinity. The fresh weight of rice grown under drought was lower compared to that grown under salinity. Total chlorophyll content decreased in both treatments. Carbohydrate analyses showed that rice grown under stresses accumulated more total sugars and sucrose compared to the control group. Moreover, rice grown under drought accumulated more sugars than those grown under salinity. In addition, the starch content of rice grown under drought was higher than that grown under salinity.