Responses of fluted pumpkin (Telfairia occidentalis Hook. f.; Cucurbitaceae) seeds to desiccation, chilling and hydrated storage

The responses of fluted pumpkin (Telfairia occidentalis Hook f.) seeds to chilling and hydrated storage at 6, 16, and 25 °C, and excised axes to fast flash-drying or slow dehydration, were investigated. Flash- and slow-drying initially enhanced germination by 20% and 7%, respectively, which was sustained despite further water loss to 0.45 g g− 1 when axes were flash-dried, but not when slowly dried. Of the seeds stored at 6, 16, and 25 °C, 3.3%, 40%, and 88%, respectively, were discarded within 4 weeks after storage because of germination or fungal proliferation. Nevertheless, axis germination of the non-visibly contaminated seeds after 4 weeks storage at 25 °C was precluded in vitro by vigorous fungal proliferation, underscoring the role of the internal fungal inoculum in obviating seedling establishment. In the case of the seeds stored at 6 °C, germinability was lost within 4 weeks, suggesting their chilling-sensitivity. Ultrastructural evidence revealed marked damage associated with chilling, while the ultrastructure of seeds surviving storage for 4 weeks at 25 °C was indicative of enhanced metabolic activity. The results reveal that fluted pumpkin seeds are recalcitrant, being both desiccation- and chilling-sensitive, and that even short-term storage in the hydrated state appears to be unachievable in practice.