Study On Physiological Characteristics Of Flag Leaf In Early Aging Near-Isogenic Lines And High Light Induced Anthocyanin Accumulation In Wheat Leaf

Wheat is one of the important food crop in China, its yield has a crucial role to food security. The wheat grain yield comes mainly from assimilation products of leaves in the latter period,especially the flag leaves. So the intensity and duration of the flag leaf function has an important role to grain yield. Early aging wheat significantly reduced the photosynthetic time of function leaves, and the photosynthetic efficiency, seriously affecting their grain yield. Study on the physiological and biochemical and genetic basis in early aging wheat has an important theoretical and practical significance.to understand the causes of premature senility, and breed high yield wheat varieties.In this experiment, the test material is wheat near-isogenic lines and the normal strains, which separated from F8 in Xiaoyan 54×8602. After the flag leaf fully expanded, based on the agronomic traits differences, photosynthesis and physiological and biochemical characteristics of late growth period between the two lines, discussed the early aging characteristics and cause of its physiological and biochemical.Antioxidants anthocyanin was studied deeply in recent years. In another experiment, Jing 411 for material, Xiaoyan 54 for controlled is used to study high light induced anthocyanins accumulation distribution, species and locate anthocyanin synthetic gene in wheat leaf.The main findings are as follows:1. Compared with normal control strains, chl b in flag leaf of early aging lines degradated rapidly after expanded, resulting in a sharp decline in chlorophyll content; Net photosynthesis rate dropped earlier and reduced violent, high value photosynthetic rate is short in relievo, photosynthetic capacity declined sharply.2. The SOD activity in early aging lines was lower than that in normal lines when at incipient stage after flag leaves expanded, so that early aging lines would not clear the .O2- in time, and the .O₂^- content accumulated rapidly. Compared with normal control strains, early aging lines AsA-GSH cycle antioxidants and enzymatic overall activity was non-significant difference. Only late in grouting, AsA-GSH system activity reduced slightly than normal control lines. Therefore, .O₂^- accumulation may be the case of premature senility to destroy active oxygen metabolism. The accumulation of active oxygen, result in leaf membrane damage , MDA accumulated rapidly .3. The enzymes SPS, SS activity of early aging lines in the process of glucose metabolism, especially SPS, and sucrose content in flag leaves was higher than normal lines; The flag leaf nitrate reductase NR activity and total nitrogen in leaves very significantly lower than normal lines. Therefore, the carbon and nitrogen metabolism disorders are a major reason for early aging wheat.5. Light-induced anthocyanin pigment types may be pelargonidin. the old leaves accumulate anthocyanin first, and its content decreased from the bottom to turn. Department of the same leaf tip the anthocyanin content decreased from tip to leaf base gradually. The anthocyanins QTL localed on chromosome 7A.