The Study On Control Measure For Flower And Fruit Of Xanthoceras Sorbifolia Bunge,a Kind Of Subtropical Oil Trees

The Xanthoceras sorbifolium Bunge is the main Tree Species as Bio-energy in north China, it has great potential development. But because of "flowers few fruit", " flower and fruit drop " and "low yield" and other reasons, severely limit its industrialization development. Therefore cultivate high yield and good quality raw material forest is the key of industrialization development of Xanthoceras sorbifolium Bunge. And flower and fruit regulation is the important measures to solve the key problem. In order to make further explorations about the internal and external cause, which effect on the flower and fruit of Xanthoceras sorbifolium Bunge. And find out the reasonable control measures. This study took the 4-year-old Xanthoceras sorbifolium Bunge in Chi Feng as experimental materials. Explore the effect of canopy microclimate and the dynamic change of endogenous hormone on the flower and fruit. At the same time carry out the test such as spraying boric acid, spraying sucrose, thin flowers, picking and so on. Provide the theory and practice base for improving the existing measures and the exogenous hormone spraying, to improve yield of Xanthoceras sorbifolium Bunge and promote its industrialization development. The main results were as follows:(1) The temperature and humidity between different directions and areas of the canopy were no significant differences in addition to the daytime temperature difference. The effect of different directions on the environmental factors was weak. There was no significant difference between light in different directions but showed in different regions of the canopy as below:upper outer> under outer> upper inner> under inner. The fruit-set rate and fertile flowers proportion of next year in the different areas of the canopy also showed the same trend as the light. Through the correlation analysis, the fertile flowers proportion, fruit-set rate and other indicators in different regions had a significant difference. Content seed oil had no significant difference between different regions. Fertile flowers proportion, yield, fruit-set rate all had significant positive correlation with light.(2) The content of IAA in fertile flowers is about 59%-262% higher than sterile flowers during the whole florescence of Xanthoceras sorbifolium Bunge. Before the full-bloom stage, the content of GA3 in sterile flowers is 63%-215% higher than fertile flowers and after that the content of GA3 and ZT in fertile flowers are 12%-19% and 31%-69% respectively higher than those in sterile flowers. During the whole florescence the contents of ABA in sterile flowers is continuously elevated and in fertile shows a trend of rise first then fall. During the whole fruit growth period, the contents of GA3, ABA and ZT show a trend of rise first then fall and keep high content in a rapid growth period. The contents of ABA and ZT respectively reach the maximum 1047.754ng/g.FW and 992.328 ng/g.FW at 30 days after flowering. The contents of GA3 reach the maximum 1923.020ng/g.FW at 40 days after flowering. At the same time, the content of IAA shows a trend of just like "M". The first peak appears at 20 days after flowering then the second peak appears at 50 days after flowering. The balance between ABA and IAA reflects the process of flowering and falling. The content of ABA and ZT affect the fruit expansion growth. GA3, IAA and ABA affect the phenomenon of young fruit drop. In productive process, we can try to spray IAA or GA3 in inflorescence extension and young fruit period to reduce its premature flower and fruit drop, increase the yield.(3) Spraying sucrose at the early sprouting period could significantly increase the proportion of fertile flowers. The proportion of single inflorescence could up to 59%. And single branch could be up to 84.5%. Spraying 0.3% to 0.5% sucrose solution was the most significant for fertile flower proportion of single inflorescence and fruit set percentage. High concentration (1.5%) sucrose solution would reduce its fruit set percentage. Spraying boric acid solution at full-bloom stage, the fruit set percentage was significantly higher than that spraying early flowering stage and before flowering. Spraying 0.05% to 0.3% boric acid solution could significantly increase the fruit set percentage and improved the fruit quality. And 0.2% boric acid solution was the best. The seed setting rate could reach 5.6%. Compared to the controls, it was 47.4% higher. Therefore, in the actual production, we can spray 0.3% to 0.5% sucrose solution at early germinating stage in order to increase the proportion of fertile flower. At the same time, spray 0.2% boric acid solution at full-bloom stage to increase the fruit set percentage and improve the quality purposes.(4) Thinning fertile flowers could significantly improve the fruit-set rate in florescence elongation stage. There was no significant effect of thinning sterile flower at this period. Thinning according to the length of terminal inflorescence could improve the fruit-set rate and the 1/3 thinning strength was best. It could make the fruit-set rate significantly increase 57.5%.Picking could significantly increase soluble sugar and starch content of leaves in the process of flower bud differentiation. The carbon nitrogen ratio could significantly improve 6.6%-23.2% by picking. It would be beneficial to promote the process of flower bud differentiation.