Studies On Photosynthetic Characteristics And Starch Metabolism Of Four Sweet Potato Varieties

In this paper,two different types of sweet potato were used to study the relationship between photosynthetic characteristics and yield of sweet potato,the regularity of soluble sugar synthesis and starch accumulation in root enlargement stage and the dynamic change of starch content during root storage.The conclusions were as follows:1.The net photosynthetic rate of sweet potato was different because of different varieties.The net photosynthetic rate of high starch sweet potato was significantly higher than that of low-starch sweet potato.The variance analysis of yield traits of different types of sweet potato showed that the the percentage of dry matter,starch yield and fresh potato yield of high-starch sweet potato were significantly higher than those of low-starch sweet potato.The results showed that that the stronger the net photosynthetic rate,the more photosynthetic product accumulation,the more easily yield crops.2.The transport and distribution of soluble sugar in sweet and potato varieties with high and low starch types were closely related to the accumulation of starch in root.The accumulation of soluble sugar in the leaves of sweet potato was consistent with the change of starch accumulation in sweet potato.The accumulation of soluble sugar in stems and leaves was still at a high level at the later stage of expansion,but the rate of starch accumulation decreased to the lowest value,and no more starch was synthesized.3.The starch content of sweet potato roots decreased with the increase of storage time,and the starch descending rate of high starch sweet potato varieties was slower at low temperature,so the low temperature conditions were more suitable for the storage of high starch varieties.The soluble sugar content in the roots of sweet potato was the highest and then decreased,and all of them were higher than the initial values.