Study On The Mechanism Of Growth In Fritillaria Thunbergii Miq.

This thesis deals with the processes of the disintegrationand transport in the bulb and the mechanism of releasing dormancywith low temperature in Fritillaria thunberqii Miq.. Apreliminary study was also conducted on its cold adaptability and(?)echanism of releasing dormancy with low temperature in itsseeds.When the bulb disintegrated, several layers of parenchymal storage cells near the inside cortex were degraded first, and forming a clear breaking cell zone. The results of physiological and biochemical estimation showed the diastase for disintegration of bulb inner cells was transported from the bud and inside cortex, but the acid phosphatase was synthesized by bulb inner cells themselves.The starch in the storage cells was degraded to sucrose and then transported to the new organ. The metabolism of the bulb and bud becomes active before 20-25 days the bud germinating out of the ground. During the starch grain degradation, its plastid shell became thickened, and, the mitochondrion, endoplasmic reticulum as well as golgiosome of the cell played an important role for the whole process. In addition, the vescicles were shown either the importance on the cell disintegration and materials transportation. Besides, the plasmodesmata presented an efficient canal for the intercellular transportation.In the process of releasing dormany with low temperature of Fritillaria thunbergii Miq., the contents of internal GA3 in bud and bulb were increased processionly, but the internal ABA could'nt be detected constantly during the whole process. The results of several physiological estimations and histological as well as cytochemical studies indicated that the whole process of releasing dormancy with low temperature in Fritillaria thunbergii Miq. could be divided into four stages. Futhermore, before and after releasing dormancy the ultrastructure of the cells inside cortex which initially degraded were changed significantly. When the Fritillaria thunbergii Miq. was under the severe cold condition, the ultrastructures were also changed on the plastid, mitochondrion and nucleus in the cells of bud and bulb.When the dormancy of seeds in Fritillaria thunberqii Miq. were released by the temperatures of 8-10℃ and 3-5℃, many physiological parameters were both changed similarly in general, but the duration of timing was different.This study will be beneficial for the cultivation and production of Fritillaria thunbergii Miq., on the theoretical basis.