Osmoconditioning as a Means of Counteracting the Ageing of Pepper Seeds during High-temperature Storage

Abstract

Sweet pepper seeds were osmotically conditioned in 0.4 M mannitol solution for 4 d (at 25 °C, in darkness) before or after storage at 35 °C for up to six months, and their germination and viability was compared with that of untreated seeds stored under the same conditions. Seeds that had been osmoconditioned prior to storage retained a high rate of germination and germinated to a high final percentage (from 80 to 50 per cent) at both 15 and 25 °C throughout the storage period. By contrast, both the rate and total level of germination of untreated pepper seeds declined rapidly at both germination temperatures, and by three months of storage the total level of seed viability was already less than 10 per cent. Seeds that were first stored at 35 °C, and then osmoconditioned just prior to germination, showed a decline in germinability which when tested at 25 °C was the same as for untreated seeds, while tested at 15 °C occurred at a slightly slower rate than for untreated seeds. It is evident that osmoconditioning prior to storage, in addition to the acceleration of germination, resulted in a dramatic delay of the ageing rate, thus increasing considerably the longevity of seeds. On the other hand, osmoconditioning after storage did not seem to have any significant effect on seed viability, though it enhanced the germination rate.