Abstract

Soil salinity is the major problem in arid and semi-arid regions, where rainfall is insufficient to leach salt and excess of sodium ion and it is one of the major constraints to the sustainability and expansion of rice cultivation. The depressive effect of salinity on germination could be related to a decline in endogenous levels of hormones. Presoaking seeds with optimal concentration of plant growth regulators (PGRs) has been shown to be beneficial to growth and yield of some crop species under saline conditions. It is extremely important to standardize the concentrations of PGRs as the activities changes drastically with concentrations. Therefore, we have used eight different concentrations of four PGRs along with absolute control and salinity stress treatments known to alter the germination viz., gibberellic acid, kinetin, salicylic acid and brassinosteriods and measured various physiological traits associated with germination. In case of germination percentage, brassinosteriods at 0.005 ppm was found to be the best as it registered highest germination percentage followed by gibberellic acid. Higher dry matter production was found in seeds treated with gibberellic acid and kinetin that recorded 37.4 % higher dry matter production than control. The critical enzyme in germination, a-amylase activity was higher in seeds treated with 500 ppm of gibberellic acid. These results strongly suggest that PGRs at optimum concentrations could be effectively used for improving germination associated traits undersalinity condition in rice.

Keywords: Plant growth regulators, Rice, Salinity stress