Studies On The Changes Of Physiological And Biochemical Characteristics Of Toona Sinensis Seeds During Initial Germinating Stages

The seeds of Toona sinensis were cultivated at (25±1)℃and the metabolic mechanism during initial germinating stages was discussed by measuring the changes of moisture content, respiratory rate, stored materials, enzymes activities and hormone contents.The results were showed as follows:1.The cotyledon cell of Toona sinensis seeds contains abundant black granules and lipid materials, and they degraded sharply after incubation for 18h.2.Changes of moisture content and respiratory rate were not absolutely similar.3.Stored substance were degraded, conversed, and utilized during initial germinating stages.But the endosperm did not degrade obviously during the first 27h and decreased sharply during the latter stage of cultivation.4.Activities ofα-amylase,β-amylase, proteinase and ACP were increasing during initial germinating stages and the peak value appeared at radicle emergence.5.The activities of PGI, MDH and G-6-PDH and 6-PGDH increased during initial germinating stages.PGI activity increased at first then decreased, and those of MDH, G-6-PDH and 6-PGDH were increasing all the time, but MDH increased a little and maintained in a low level.6.The content of ABA in the embryo gradually decreased and that of GA3 and IAA increased during the initial germinating stages, but those of ZR increased at first then decreased.The ratios of GA3/ABA, ZR/ABA and IAA/ABA gradually increased, and were consistent with seed germination of Toona sinensis.