Studies On The Changes Of Physiological And Biochemical Characteristics Of Pinus Tabuliformis Seeds During Initial Germinating Stages

The seeds of Pinus tabuliformis Carr. 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 endosperm cell of Pinus tabuliformis seeds contains abundant black granules and lipid materials,and they degraded sharply after incubation for 27h.2. Changes of moisture content and respiratory rate were absolutely similar and could be divided into three stages as follows:rapid increase,much slowly increase and anew rapid increase.3. Stored materials 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,proteinase and ACP were increasing during initial germinating stages and the peak value appeared at radicle emergence. Meantime,activity ofβ-amylase increased greatly with peak value at 45h and decreased afterwards.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 endosperm gradually decreased and that of GA3 increased during the initial germinating stages,but those of IAA and 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 Pinus tabuliformis.