Study On Relationship Between Off-season Floral Induction In Longan And Nutrition Of The Carbon And Nitrogen

In this research, By Field-grown and potted trials,'Songfengben'Longan (Dimocrupus longan lour. cv. Songfengben) (late-maturing species) and'Fenglisui Longan'(Dimocrupus longan lour. cv. Fenglisui) (medium species) were employed as materials for application of potassium chlorate induced off-season flowering in August 2008 and September 2009. From the perspective of carbon and nitrogen,during flower bud differentiation of physiological, dynamic changes of photosynthesis, carbon and nitrogen metabolism,sucrose-related enzymes, and endogenous hormones on the role of regulation of carbohydrate formation and accumulation was studied to explore mechanism of off season floral formation induced by potassium chlorate application in longan. The study yields the following results:1,The results of research on Daily and dynamics variation of photosynthesis show that, during flower bud differentiation of physiological, along with the decline of photosynthetic rate, stomatal conductance and transpiration rate decreased, the intercellular CO2 concentrations conversely increased, while chlorophyll a, chlorophyll b and carotenoids have decreased after the 7th, which demonstrate that decline of photosynthetic capacity was mainly due to the inhibition of photosynthetic apparatus activity. These results indicate that the reduction of photosynthetic activity is an important physiological characteristic.2,By studied on nutrition metabolism of leaf carbon, the results show that accumulation of carbohydrates during flower bud differentiation of physiological is conducive to flower bud differentiation. Soluble sugar, fructose and glucose content were increased, and the sucrose content was significantly increased, while starch content decreased. Further By analysis and comparison on relationship between the carbohydrates and sucrose-related enzymes, SS activity has positively significant correlation with sucrose content, while negative significant correlation with the starch content SPS activity and fructose or starch content has negative significant correlation; AI activity has negative significant correlation with sucrose, however, positively significant correlation with fructose. accordingly during flower bud differentiation of physiological, accumulation of carbohydrates is an important physiological index of inducing off-season flowering of longan.3,Results of research on nitrogen metabolism show that during flower bud differentiation of physiological, decline in total nitrogen and nitrate nitrogen content, Amino acid nitrogen content is favourable to flowering, and then, reduction of the soluble protein content in the prophase and in the anaphase increases indicate Early leaf physiological differentiation protein may have a transfer to reproductive development center for the flower bud differentiation to provide the necessary structure material. And then, study and analysis on the C/N value indicated that, in the prophase of flower bud differentiation of physiological, high value of C/N is conducive to flower bud differentiation.4,Has studied the relations between the carbohydrates and changes of endogenous hormone levels, finally indicated that: the IAA and the fructose have the remarkable relevance, but the starch achieves a negative significant correlation. the GA3 was a significant negative correlation with starch, while glucose was significantly positively correlation GA3. ABA and the soluble sugar assume the remarkable inverse correlation, to have the extremely remarkable inverse correlation with the sucrose, to have positively significant correlation with the starch. zeatin has significantly positively correlated with sucrose and glucose.This showed that the hormone may play a regulating role in carbohydrate distribution and transformation, making it to be more advantageous in becomes the direction of flowering transfer and transformation.In summary, in the critical period of flower bud differentiation of physiological, various material transformations in plant leaves have been taken place: the degradation of photosynthetic pigments, photosynthetic capacity decreased, accumulation of soluble sugar, sucrose, fructose and glucose, massive hydrolysis of starch, as well as mutual metabolism between carbohydrate and related enzymes, the content of the total nitrogen and the nitrate nitrogen reduces, the content of Amino acid increase, the C/N value increases obviously. It can be considered: in the critical period of flower bud differentiation of physiological (20d) is a critical period of inducing off-season flowering of longan, synthesized above dynamic change of accumulation of carbon and nitrogen nutrient, had strongly indicated that high value of the C/N is advantageous to the flower bud differentiation. This provides an important theoretical basis for off-season flowering of longan in the future...