| Mathematic model of sugar beet (Beta vulgarisL.) bolting in the first growth year induced by temperature and light was established, and the dissection structure of steffl apex meristem, the standard of physiology and biochemistry, the content of endogenous hormone and gene expression in the process of bolting were analyzed. The mechanism of bolting in the first growth year was studied preliminarily.The mathematic model of bolting was established by the design of quadratic quadrature votation combination mainly revealed that environmental factors such as temperature, day length and day number affected bolting in the first year . Temperature played the most significant role in controlling bolting. Day number had the smallest role compared with temperature and day lenth. One single factor analysis showed that temperature had a negative correlation with the ratio of bolting. The ratio of bolting was the biggest when the temperature was at from 4 to 5癈. After that, it decreased gradually with raising temperature. Photoperiod also had a great influence on the ratio of bolting. Day length had a positive correlation with it. The ratio of bolting was the highest when day length was from 15 to 17 hours. Day number had a positive correlation with it .The analysis of interaction between temperature and light indicated that they had an apparent interacting effect on the ratio of bolting. Temperature can compensate with light to make the ratio of bolting higher.Sugar beet is a kind of rosette leaf bunch plant. The traditional idea is that the growth of inflorence is a way of reproductive growth and bolting ( elongation of stem internode )symbolizes the beginning of reproductive growth .that is to say, it is a transition from vegetation growth to reproductive growth. However, in this experiment with temperature and light inducing bolting in the first growth year and stimulating the differentiation of flower bud, the growing of cauline leaf (belong to vegetative growth) lasted for an unexpected long tine when the growing of inflorence was being observed. But flower bud differentiation was not found at this time. This result was different from the previous result that flower bud had already differentiated before the elongation of stem (Pan ruizhi, Plant Physiology, second edition). Moreover, the dissection section of the stem apox meristem at this time showed that it was seedling apex and had a layer of tunica. Therefore,sugar beet bolting may belong to vegetative growth from the aspect of morphology dissection. The traditional idea that bolting is the boundary between vegetation growth and reproductive growth should be reconsidered.Many metabolic ways in sugar beet were changed after the seedling receivedtemperature and light induction to promote bolting and blooming. The activities of ascorbic acid peroxidase and cytochrome oxidase related to respiration first rose after induction and then decreased gradually while polyphenol oxidase activity increased continuously; Peroxidase activity decreased gradually with the growing of sugar beet; Peroxidase was located on cell wall and vacular membrane and cytochrome oxidase was on mitochondrial membrane. More peroxidase and cytochrome oxidase appeared on cell wall, vacular membrane and mitochondrial membrane respectively after induction but then they decreased gradually, which showed the same changing regularity with their activities; Proline content varied little before and after bolting; Protein content increased dramatically before bolting and blooming; Some unique proteins were synthesized after bolting: 28KD, 37HK 45HX lOSKDand 116KD. The enzyme changing and protein synthesization may have a relation with the expression of bolting gene.Endogenous hormone (IAA, GAS and ABA) from bolted and non-bolting plants in the first growth year and mother roots at different growth stages were assayed by high-pressure liquid chromatography, which indicated that the content of GAS and ABA, especially, the value of GA3/ABA had a close relation with bolting in the first growth y...
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