Differential response of rice genotypes to mild and severe osmotic stress during seedling stage

Though the response of plants exposed to severe drought stress has been studied extensively, little is known about how plants adapt their growth under mild drought stress conditions. In the present study seeds of sixteen genotypes were germinated under three treatments: non stress, 1% mannitol and 2% mannitol and the result revealed that average germination percentage was found to be low in both the treatments compared to non stress. However, better plant vigour on the basis of shot and root length was observed in 1% mannitol treated seeds compared to untreated and 2% mannitol treated seeds. Other traits like total protein content, catalase and peroxidase activity were also more at 1% mannitol compared to nonstress and 2% mannitol treatment. Among all the genotypes tested, AC 42994, AC 43030 and AC 43012 out performed in plant vigour as well as anti oxidant enzyme activities compared to other genotypes and tolerant check.

Author : Goutam Kumar Dash and P Swain*