Studies On Dormant Characteristic And Growth And Development Of Apricot Trees Under Protected Cultivation Conditions

There are two parts in this trial. One is that the chilling requirements of 24 cultivars of apricot, Dynamic state of H2O2 content .changes in antioxidate system, the dynamic changes of carbohydrates and the free proline were estimated and measured. The other is that the floral bud differentiation, fruit development, shoots growth, and Pn of apricot under protected cultivation conditions were observed and measured, and discussed the effect of breaking apricot bud in Ca(CN)2. The results were as follows:1. There were difference among chilling requirement of the apricot varieties given by different models. Chilling requirement was related to not only variety genetic characteristic, but also the environment conditions .so the chilling requirement was different for various cultivars, the basic trend was vegetative buds is bigger than floral buds' for one cultivar in a year.2. The content of H2O2 in shoots and buds of dormant apricot increases under low temperature, and it decreases after rest released, which indicated the changes of content of H2O2 is related to effect of breaking dormancy and activity of SOD, POD and CAT. Three antioxidate enzymes were analyzed during dormant period. It indicated that SOD activity was high at earlier stage, then dropped to a low activity. With the chilling requirement coming, only rising slighting after the end of dormancy, POD activity was low in earlier stage, then rose steadily, and the trend was similar to changing of H2O2 content, CAT activity was also low in earlier stage, with the chilling requirement accumulation, it rose quickly, dropped sharply with the end of endodormancy.3. During the winter dormancy, with the chilling requirement coming , The content of starch decreased and the content of soluble sugar increased. The content of free proline increased, it conversed while the end of endodormancy.4. Ca(CN)2 has a little effect on breaking the buds of apricot.5. Suture diameter and polar diameter growth curves of "Jintaiyang" and "Luotuohuang" apricot in greenhouses, whether basic temperature or high temperature, were both double sigmoidal growth curves.6. There were two fast-growing periods for the growth trends of shoots of "Jintaiyang" inside the greenhouse, One being 7th-8th week after blossom, i.e. the beginning of April, another being 16th-18th week after blossom, i.e. from the beginning to the middle of June. There was only one fast-growing for the shoots in the open field, which happened 11th-12th,i.e. the beginning of June. The shoot growing in the greenhouse far exceeded those in the open field.7. In Taigu, floral bud differentiation process of "Jintaiyang" apricot in greenhouse was: Bud differentiation began the middle of May, Calyx being from the end of June to the beginning of August Petal being from the beginning of July to the end of August, Stamen being the middle of July to the beginning of September, Pistil being from the middle of July to the middle of October .and appeared pistil degeneration phenomena.8. Average Pn in a sunny day in the open field appeared gently double peaks curve, but being typical double peaks curve inside the greenhouse, In cloudy, being gently double peaks curve in the open field and single peak inside the greenhouse. Season Pn in greenhouse emerged three peaks curve and double peaks one in the open field.