Effect of ascorbic acid on seed germination of three halophytic grass species under saline conditions

Abstract

Abstract Grasses on the P akistani coast are moderately to highly salt tolerant and have potential for utilization as a cash crop. This study was designed to determine whether seed germination of three halophytic grasses ( P hragmites karka, D ichanthium annulatum and E ragrostis ciliaris ) could be improved by exogenous application of ascorbic acid ( A s A ) under saline conditions. Seeds of P . karka were germinated in varying concentrations of NaCl and A s A under different temperature regimes, and seeds of D ichanthium annulatum and E ragrostis ciliaris were germinated at optimal temperatures only. In P . karka, concentrations of A s A (5 and 10 mM) alleviated the salinity effects better at cooler and moderate thermo‐periods, whereas higher concentrations (20 mM of A s A ) failed to improve germination under all temperature regimes. A s A was ineffective at a warmer thermo‐period (25/35°C). The rate of germination also increased at all thermo‐periods with the application of A s A except at 25/35°C under saline conditions. Application of A s A improved the germination of E . ciliaris seeds under saline conditions but was inhibitory for D . annulatum in comparison with the untreated control. The rate of germination followed the similar pattern as that of seed germination. Results indicate that A s A has the ability to partially alleviate the effect of salinity on seed germination of some grass species under optimal temperature regime.