GERMINATION OF PEA SEEDS EXPOSED TO SALINE STRESS

ABSTRACT Salinity up to 200 mM NaCl has very little effect on the germination of Alaska peas as expressed by root protrusion. However, it strongly affects the emergence of the epicotyl. This effect is expressed by slower increases of fresh weight and of the water potential of the embryonic axis and results in delayed emergence. The imbibition of the cotyledons is apparently not affected. Parallel to inhibition of epicotyl emergence, salinity induces accumulation in the cotyledons of ABA and proline, although the rate of increase in content of these two substances is not identical. It is proposed that on exposure of pea seeds to salinity ABA accumulates in the cotyledons, is transported to the embryonic epicotyl and inhibits water uptake. When proline accumulates, water uptake is resumed and epicotyl emergence occurs.