Study On The Relationship Between The Sucrose Metabolizing Enzymes And Sucrose Accumulation In Sugar Beet

In this dissertation,Tianyan7, Tianyan8 and shuangfeng8 sugar beet was selected as experimental sample,and experiments were made in the horticultural station of NEAU in 2008. The studies on the activities of SS (the direction of synthesis and decomposition), SPS(Suerose Phosphorus Synthetase),AI (acidic sugar-converting enzyme) and NI (neutral sugar-converting enzyme) were conducted in both roots and leaves of sugar beet ,as well as in the different nitrogen levels conditions, through the period of the enzyme in the simultaneous determination of the enzyme based on the performance characteristics of different periods in the analysis, a preliminary study the roots of sugar metabolism and the accumulation of the inherent mechanism. The main objectives of this experiment were to preliminarily understand the mechanism of sugar metabolism and accumulation in the root of sugar beet by measuring and analying the activities of mainly related enzymes.The result could be drawn as follows:During the whole period of sugar beet growth, the activities of the key sugar metabolism enzymes of the sugar beet roots and leaves varied in coordination with the change trends similar to each other.The activity of SPS,decomposition of SS, Synthesis of SS and AI are similar;only the activity of NI different from other enzymes.In the roots,the trend of the activity of SPS is similar with the activity of SS,indicating that they have certain synergies.The most productive period of the decomposition activity of SS is also the most productive period of the activity of SPS,show that the decomposition activity of SS provide guarantees for the normal of the SPS.In the sugar metabolism of the leaves,the activity of NI and the decomposition activity of SS paly a main role in the decomposition of sugar at the earlier growing stage,but the activity of AI and the decomposition activity of SS at the late growing stage. Different nitrogen levels have some effect on the activity of the key enzymes of the sugar metabolism of the sugar beet.The nitrogen fertilizer increase the activity of SPS ,in certain nutrients conditions of soil, nitrogen 120kg/hm2 improve the activity of SPS best. Applied nitrogen fertilizer, the synthesis and decomposition activity of SS in the sugar beet roots markedly improved, show that the activity of SS play a great role in the roots. The decomposition activity of SS paly a main role at the earlier growing stage and the synthesis activity of SS paly a main role at the late growing stage. With the increase in the proportion of nitrogen, the activity of AI in the sugar beet leaf and the activity of NI in the sugar beet roots gradually increased.The content of total soluble sugar in the sugar beet roots and leaf showed a single peak curve, reaching a peak was the most productive period of sugar metabolism. The content of fructose is higher at the earlier stage and lower in the seedling stage. During the growth period,the content of total soluble sugar, fructose and sucrose in sugar beet roots is higher than that in sugar beet leaves, show that root is the main sugar storage organ . The content of total soluble sugar, fructose and sucrose increased accompany with the increasing of the proportion of nitrogen, which may indicate that nitrogen nutrition play a promotion on the synthesis and accumulation of sugar. Under the different proportion of N, the content of chlorophyll of sugar beet leaves increased with the nitrogen application rate increasing. Nitrogen application and the ratio of root and cown were the negative correlation. the dry weight of sugar beet roots and leaves was "S" curve; and the dry weight increased with the amount of nitrogen fertilizer increased.The key enzyme of sucrose metabolism in sugar beet at earlier and late stage had a greater impact on the main products of sugar metabolism in leaves,but in roots at middle stage.The decomposition enzymes of sucrose metabolism had a greater impact on the main products of sugar metabolism at earlier stage,and the synthesis enzymes of sugar metabolism had a greater impact on the main products of sugar metabolism at late stage.