Study On Hight Synthetic Effiency And Low Light Tolerlance Germplasm In Peach (Prunus Persica Stoke.)

It is important to select the germplasm of high photosynthetic efficiency andLow Light tolerance for under structure culture and enlarging the area oftemperate-fruit , and increasing the yield . In the experiment, six peach cultivars weretreated by three different extent of shading (i.e. complete natural light, 70% naturallight and 30% natural light). By studying the Correlation analysis betweenmorphological and physiological index and photosynthetic efficiency, we can identifythe exact and ordinary indexes, and apply them to select ideal germplasm. Theexperiment also studied the morphological and physiological changes of peach in lowlight condition and analysed the physiological mechanism . At the same time we lookfor the convenient and reliable indexes to identify low light tolerance of peachmaterials. Some judging system which can be used to select the germplasm of highphotosynthetic efficiency and Low Light tolerance was also proposed. The results show: (1). The Correlation indexes between the integrative morphological index, photosynthesis at 9:00, the ratio between photosynthesis at 9:00 and respiration and plants'dryweight are prominent. so, these indexes can be used to select germplasm, andintegrative morphological index is the best. (2). Under the shading treatment, the relativity between the synthetic index andincrement of the whole plant's dry weight is prominent which means the synthesisadjustment is seasoned with shading conditions, i.e. the change of Cs(conductance ofstoma), Tr(transpiration rate), Apparent quantum yield. The morphological change iscomplex under shading treament. (3). The Correlation indexes between the Cs, Chlorophyll a/b value, proline contentand the increment of plants'dry weight are prominent under moderate shadingtreatment .so , these indexes can be used to select germplasm. It is unsuitable to selectgermplasm under severe shading treatment. (4). Some principle shoule be noticed in selecting germplasm. Firstly, we should makesure which level of shading treatment is suitable.Secondly, the purpose which selectgermplasm is to identify easy, exact index. Thirdly, some integrative morphologicalindex is the best choice. At the same time, the physiological change should bereferenced to select the peach germplasm.