| Lotus root (Nelumbo nucifera Gaertn) is a perennial hydrophytic herb plant. It is one of the most archaic dicotyledon and it also has many monocotyledon's characters. Lotus root originates in India and China, which is planted over China , Japan and other Southeast Asian countries . Fresh lotus root, powder of lotus root and seeds of lotus , which are the products of lotus root, are considered as good tonic foodstuffs. They contain a large amount of starch, protein, multivitamin and mineral nutrition ,and they are thought as excellent characteristic vegetables and fine non-staple foodstuffs in China and they are also good for the nutritional health care. Recently, with the continual adjusting of plant industry in China and the rapid exploiting of lotus root products, we make more and more profits from the export ,and lotus root has become one of the most important vegetables. We can see that the future of produce and process industry for lotus root is very vast.Now, there are few study of lotus root's quality development, and we also has no special varieties for processing. So, we can't choose the raw material scientificly according to the require of processing , it often reduce the culture benefits. So, to prove up the carbohydrate metabolism and its relationship with quality during lotus rhizome development and storage in fields through the winter is what we should do urgently.Based on the former studies, this paper works on the carbohydrate metabolism of different varieties, configuration of amyloid and starch gelatinization characteristic during the lotus rhizome swollen and storage in fields through the winter. The results are as follows:1. Carbohydrate metabolism of four cultivars of Nelumbo nucifera Gaertn during the lotus rhizome development was studied. The results showed that glucose content increased continuously from the start stage to the middle stage of lotus rhizome development, and decreased sharply with starch increasing at the end stage and theextent of decreasing was 60%-80%; fructose content increased between the start stage and the early stage, and decreased 60%-80% with lotus rhizome development, then rose again in matured rhizome; from the start stage to the early stage sucrose levels of four cultivars all increased, at the early stage sucrose content was 3.0-7.3 times more than the start stage, then slightly decreased between the early stage to the middle stage, and from the middle stage to the end stage sucrose contents of four cultivars all increased again, which showed sucrose was most accumulated at the end stage. The changes of contents of total dissoluble sugar had the same style as glucose.2.Changes of starch ( including amylose and amylopectin), glucose , fructose and sucrose content in lotus rhizome during storage in field through the winter were studied. The result showed that the main storage nutrition of lotus rhizome was starch. In matured rhizome of Wuzhi No.2 starch content achieving 12.8%, was the highest among the four varieties, while E lian No. 1 's achieving 11.2% was the lowest. Before the end of November, carbohydrate content in rhizome almost remained the same; from the end of November to the end of January, with the temperature successively running down, a large amount of starch decomposed and the content decreased 19.6%-26.4%,the content of glucose and fructose increased significantly and a part of them then transformed into sucrose for storage; from the end of March to the end of April, a large amount of starch in rhizome broke down again, the content decreased 18.7%-33.9%, the content of glucose and fructose increased significantly for the second time. In the whole course, starch breaking down gave priority to amylopectin.3. The observation of amyloid form during lotus rhizome development by SEM indicated that in different stage, amyloid consisted in cells with different forms; at the start stage, there were only a little single amyloid distributed in each cell; at the early stage, the volume of amyloid enlarged and the amount manifolded, but some amyloid began to break...
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