Studies On Seed Physiological Characteristics Of Ceratoides (Tourn.) Gagnebin

The thesis studied on the physiological characteristics of Ceratoides L . The contents were composed of the germination characteristics, the resistance of seed and seedling, the nutritive composition, the hormone content, the seed production and the molecular physiology, we studied the deterioration mechanism of seed as well.The proper germinating temperature of Ceratoides L seed is the constant temperature of 25 C and variable temperature of 15-25 C; The seed belongs to nonphotosentive one; The water requirement of germination ranged from 4.05 to 6.95 times of dry weight , and the minimum requirement existed obvious differences between materials ,in which C. arborescens requirement was the lowest (4. 05 time of seed dry weight);The seed quickly absorbed water during germination , The speed generally was 0. 6-0.7g/h.g seed and seed imbibtion was saturated after 7-8h. Under the same environmental condition, the physiological activity of seeds displaied differences between species , ecotypes or plant with different age. The physiological indexes of C.arborescens all obviously dominated other species. The seeds of Ceratoides L. had great power of drought resistance and salt resistance, meanwhile, there are great differences between species, ecotypes or plants with different age.The nutritive composition and hormone contents of seed existed differen- ces between Species, ecotypes or plants with different age. The correlation between sugar content and seed physiological activity was not obvious, while N,P contents and seed physiological activity obviously correlated. The appropriate measures could remarkably improve the. production and quality of seeds of Ceratoides L. in field .The analysis of isozyme and RAPD of seeds dedicate that there were abundant variations on isozyme and genomic DNA, there were also ecologi-cal multiplicity between species ,ecotypes or plants with differents age in Ceratoides L. There were obvious differences between reproductive organ (seed) and nutritive organs (root, stem and leaf). The result of cluster analysis showed that the materials with fewer morpholo- gical difference and nearer geographical distribution had nearer relationship. This result was in keeping with the result of morphology on the whole and could provided molecular basis for the systematic study of Ceratoides.L plants.The deterioration of seed was due to two reasons. That were genetic factor and environmental factor. First, the Ceratoides.L seed belongs to low nutrition seed and it' s nature longetivity was short; second, because of the harsh environment during seed developing ,seeds were short of nutrition and the development were uncomplete; Third, because of the unsuitable storage condition, especially because the water contens was higher, the seed deteriorated rapidly.