Studies On Methods For Breaking Dormancy And Germination Physiology Of Magnolia Officinalis Rehd. Et Wils. Seeds

Magnolia officinalis Rehd. et Wils. is an unique, precious tress species commonly used in Chinese herbal medicines, which belongs to the 3st-class protection of national critical protected endangered plants. It can be used as medicine ,timber and ornamental plant.The thesis systematically studied the methods for overcoming seed dormancy of Magnolia officinalis and the dynamic changes of physiological and biochemical characteristics during the stratification. The main results were as follows:1. The study of the methods for overcoming dormancy showed that the seed dormancy could be effectively overcome by both alternative (warm and cold) stratification and cold stratification, and alternative stratification is better than warm stratification.2. The treatment of exogenous GA₃ could quickly break the dormancy of Magnolia officinalis seeds, and the seed germination percentage ascended with increasing GA₃ concentration. The seed germination percentage could be 70% after soaking with 1000mg·L^-1GA₃ solution for 36h and then treating with fluctuating stratification (day and night) for 40d, which was best in all treatments.3. The seed storage materials were degradated ,conversed and utilized during the course of breaking dormancy, which could provide plenty materials and energy for seed embryo growth. Meantime, the activities of enzymes related to metabolism was gradually enhanced and the changes of endogenetic hormones were synchronistic with the seed germination. The treatment with exogenous GA₃ accelerated the physiological and biochemical process in seed germination .