Influences of Photoperiodism and light treatments during fruits storage on the phytochrome and on the germination of Cucumis prophetarum L. and Cucumis sativus L. seeds.

Day length, temperature, light quality and hormone treatments given to plants during the ripening of their seeds have been shown to influence the subsequent germination of these seeds. The present work demonstrates that the light conditions, SD, LD or continuous dark, red or far-red light, during storage of ripe fruits of Cucumis prophetarum and Cucumis sativum strongly influence the capacity of seeds, later removed from these fruits, to germinate in darkness.Direct measurement of phytochrome in seeds showed that the various light treatments (continuous dark, red or far-red light but not long or short days) directly affected the quantity of photoreversible phytochrome and more importantly, the percentage of active phytochrome P 730 which is critical for germination. The possible physiological implications of those results are discussed. It seems that the environment affects the dark germination of cucumber seeds through two different pathways: a phytochrome controlled and a daylength dependent mechanism.