Effects Of Low Light On Tomato Physiology And Selection Of Low Light Tolerance Germplasm

Following more and more popular application of vegetable protective field cultivate in China, especially in tomato. There is an emergent necessity of breeding new varieties, which can adapt the environment of low temperature and light. To solve this problem, the selection of materials which can tolerate low light should be strengthened firstly. In this experiment, several tomato varieties are treated by three different extent of shading (i.e. complete natural light, 55% natural light and 25% natural light) in different developmental stages (i.e. seedling stage, blooming and setting stage). By studying the morphological and physiological changes of tomato in low light station, we look for convenient and reliable indexes to identify low light tolerance of tomato materials, and apply them to select ideal germplasm. The results show: the tomatoes whose seedling suffering low light express the tendency of spindling, the rising of SLW and LAR ,the increase of Chlorophyll content, Chlorophyll b/a value and percentage of fertile fruit, and the decrease of soluble sugar and protein content; during blooming and setting stage, it shows spindling, the increase of SLW, Chlorophyll content, Chlorophyll b/a value, POD activity and soluble protein content, the decrease of soluble sugar content and percentage of fertile fruit, and the change of Chloroplast ultrastmcture. Each index of the same varieties changes identically in different extent of low light. Tomatoes in seedling stage have no correlation with those in blooming and setting stage on low light tolerance. Relative plant height/diameter stem and relative Chlorophyll b/a value can be applied as identifying indexes of low light tolerance in seedling stage. Relative plant height/diameter stem and relative soluble protein content can be applied as identifying indexes of low light tolerance in blooming and setting stage. At last, we deduce a regression equation to evaluate the low light tolerance. Six materials which can tolerate low light in seedling stage are selected in this experiment: L. pennellii, P91, T129, T135, P3 and T141. Postgraduate: Hou xing-liang Major: Vegetable Breeding Advisor: Prof. Lijing-fu...