EFFECTS OF A LOW-TEMPERATURE PRESOWING TREATMENT ON THE GERMINATION OF TOMATO SEED UNDER TEMPERATURE AND OSMOTIC-STRESS

The germination responses of two seed lots of tomato seeds (Lycopersicon esculentum, cultivar 'Moneymaker') to a low-temperature pre-sowing treatment were investigated at 10, 20 and 30°C under ψms of 0, -0.25 and -0.5 MPa created by aqueous solutions of polyethylene glycol. After a low-temperature pre-sowing treatment, both lots of seeds germinated more rapidly than untreated controls under most combinations of temperature and polyethylene glycol concentration; the relative benefits increasing with the stress imposed. More significantly, seed treatment increased the final germination capacity of seeds under the severe stress conditions of high temperature and -0.5 MPa. Uniformity of radicle emergence differed greatly between the two seed lots. Pre-sowing treatment brought the uniformity of the poorer lot to levels comparable with, or better than, the other lot which responded less well to treatment in this respect. The physiological and horticultural implications of these results are discussed. © 1990.