SEEDBED ECOLOGY OF WINTERFAT - IMBIBITION TEMPERATURE AFFECTS POST-GERMINATION GROWTH

Seed imbibition is a critical first step in the awakening of an embryo plant. To determine if imbibitional conditions influenced post-germin ation growth, seeds of 3 winterfat (Eurotia lanata) ecotypes were imbi bed at 5 temperatures from 0 to 20-degrees-C, and at 5 oxygen concentr ations from 0 to 40%. After a 4-day imbibition period the seeds were e ither dried and weighed or they were cultured in the dark at 20-degree s-C. Seedling axial length was measured 5 times between 5 and 14 days post-germination to assure that maximum growth was measured. The study was repeated 3 times for each ecotype. Oxygen concentration had littl e effect except at 0%. As imbibition temperature increased both post-i mbibition dried seed weight and seedling axil length decreased. This i ndicates the probability for successful germination, establishment, an d survival of winterfat decreases when seeds are imbibed at 15-20-degr ees-C as compared to 5-degrees-C. Therefore winterfat should be sown d uring those parts of the year when diaspores will imbibe at cool tempe ratures. Winterfat should be imbibed and held at 5-degrees-C for 4 day s, then germinated at 15-degrees-C when testing germination.