TEMPERATURE EFFECTS ON IMBIBITION AND GERMINATION OF CUCUMBER (CUCUMIS-SATIVUS) SEEDS

Unlike horticulturally mature fruit of 'Dasher II' and 'Poinsett 76' c ucumbers (Cucumis sativus L.), two cultivars that differ significantly in their level of chilling tolerance, imbibing and germinating seeds of these two cultivars responded similarly to chilling temperatures (e .g., increases in fresh weight, time to radicle emergence, and root gr owth). 'Dasher II' and 'Poinsett 76' seeds were imbibed and germinated at 10 to 30C, and seeds germinated at 25C for 24 h were chilled at 2. 5C for various durations. In comparison, seeds from an aged lot of 'Po insett 76' seed (1989) responded very differently from the 1992 seed l ots in all experiments. The chilling tolerance level of germinating 'P oinsett 76' seed varied with the seedling age as measured by resumptio n of root growth. Our results suggest that some factor that confers ch illing tolerance is gradually lost during the early stages of germinat ion following imbibition.