| Flower bud differentiation is the basis of flowering. The tissues cultured seedlings of Siraitia grosvenorii was chosen as the material. In order to explore the potential physiological mechanisms of the floral bud differentiation of Siraitia grosvenorii and to provide the theoretical basis for improving the cultivation technology of its tissues cultured, the physiological and biochemical changes in the process of the flower bud differentiation, the effects of different concentrations and kinds of polyamines on the flower bud formation were studied in the dissertation. The main results were as follows:1. With the process of the flower formation, the content of the soluble sugar, the starch and the soluble protein increased at the very beginning, then declined, reaching to the peaks in the flower bud physiological differentiation period, so do the activities of POD, PPO and PAL. On the contrast, the activity of EST declined at first and then increased. The content of soluble sugar, starch and soluble protein in leaves of those plants whose flower bud hadn't formed were all at a relatively low level before the peak of flower bud physiological differentiation, after that time the soluble sugar increased continually, and the starch and the soluble protein had not appeared obvious reducing tendency. In the stage of flower bud differentiation, the activities of POD, PPO and PAL increased at first and then declined, too. But they were all at a relatively low level and no obvious peak value appeared. The EST activity maintained at a quite high level during the differentiation time. From the above, we can draw a conclusion that a large number of solubility sugar, starch and solubility protein, relatively high reactive level of POD, PPO and PAL, and relatively low reactive level of EST might be favorable to the flower bud formation.2. The POD isoenzyme bands were increasingly rich with the process of flower bud differentiation, two specific POD isoenzyme bands, Rf=0.20 and Rf=0.39, appeared at the period of flower bud differentiation. Rf=0.16, 0.66 and 0.73 of EST isoenzyme bands were changing throughout the growth period, in which Rf0.16 and 0.66 began to emerge after entering the period of occurring flower transition, and Rf0.73 bands disappeared after entering into the occurring flower transition and reappeared until the flowers formatted. Therefore it can be presumed that Rf0.16, 0.66 and 0.73, three EST isoenzyme spectrum bands, were possible to correlate with flower formation of Siraitia grosvenorii. Compared with the adult plants that can format flower, less POD isoenzyme bands were detected in the plant that had not formatted flowers and the bands whose Rf=0.20, 0.39 disappeared; EST isoenzyme bands whose Rf is 0.16, 0.66 did not emerge at all, and Rf0.73 band did not disappeare at the time between the flower bud differentiation and the flower bud formation. It is proved that POD and EST is closely related to flower formation from the reverse side.3. The treatments with either 10-4～10-6mol/L Spm or 10-4～10-6mol/L Spd could influence the distance between the nodes where the flower formed in a certain degree, promote the flower bud differentiation and enhance the rate of flowers occurring. While the consistence of Spm was 10-4mol/L and Spd was 10-5mol/L, the effect was most obviously, and the flowering rate was raised from the control of 100% to 122.8% and 128% respectively, and the flowering number was raised most prominently (p<0.01). While the consistence of Spm was10-6mol/L, the effect was the least evident. Studying on the Siraitia Grosvenorii whose flower bud had not formed in greenhouse, we could find out that, the treatments with either Spm 10-4mol/L, Spd 10-5mol/L or Spd 10-6mol/L could promote the flower formation, while the consistence of Spm was 10-4mol/L and the consistence of Spd was 10-5mol/L, the effect was most obviously.4. The treatments with either exogenous Spm or Spd could enhance the content of soluble sugar, starch and soluble protein and the POD, PPO and PAL activities in the leaves in the period of the nutritional growth transition to the reproductive growth, however the EST do the...
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