| Drought is one of the most important ingredients of environmental stresses, which can arose tremendous physiological change of plant. Photosynthesis is the most important physiological process, which is extraordinary sensitivity to drought stresses and have definite diversity among different plants. Color-leafed plants, as a group of special ornamental plants, applied more and more extensively in landscape greening. Some mutation of the fruit tree, such as Red-leaf peach, is belong to Color-leafed plants. So the studying of physiological responses to drought stress is not only helpful to open out physiological mechanism of red-leaf peach to stress, but also redounding to the ability of resisting stress or protecting Red-leaf peach from stress, with the feasible technological measures. In this paper, with the Green-leaf peach as control, we studied on the changes of index of stress physiology, Photosynthetic characteristic and Chlorophyll fluorescence characteristic of red-leaf peach under drought of different degrees. The results showed that:1 Studying on Photosynthetic characteristic and relative physiology index of Red-leaf peach under drought stress in summer(1)Along with the stress time extended and stress degree increased, leaf relative water content, photosynthetic pigment content and the diurnal integral value of Pn in Red-leaf peach and Green-leaf-peach were restrained in different degree, but the anthocyanin content, membrane permeability ,MDA content and Pro content increased distinctly. And antioxidant enzymes(SOD,POD,CAT)activity first arised and then declined. (2)Under drought stress in summer, AQY and CE of Red-leaf peach and Green-leaf-peach went down. Moreover the photosynthesis restraining was due to stomatal limitation early under Medium drought while the photosynthesis restraining was due to nonstomatal limitation under heavy drought. The declining of LSP and rising of LCP made the available light arrange shortened.(3)The analysis of Chlorophyll fluorescence characteristic showed that as the stress time went on and stress degree increased, the value of Fv/Fm,qP,Yield,ETR in Red-leaf peach and Green-leaf-peach decreased inapprent, while the value of NPQ rose up. (4)The gray relational grade analysis showed that the relationship between climate factors and Pn in Red-leaf peach and Green-leaf-peach were Ta in summer. While the relationship between climate factors and Pn in Red-leaf peach under drought stress were also Ta, in Green-leaf peach were Vp.2 Studying on Photosynthetic characteristic and relative physiology index of Red-leaf peach under drought stress in autumn(1)Along with the stress time extended and stress degree increased, leaf relative water content, photosynthetic pigment content and the diurnal integral value of Pn in Red-leaf peach and Green-leaf-peach was restrained in different degree, but the anthocyanin content, membrane permeability,MDA content and Pro content increased distinctly. And antioxidant enzymes(SOD,POD,CAT)activity first arised and then declined. (2)Under drought stress in autumn, AQY and CE of Red-leaf peach and Green-leaf-peach went down. Moreover the photosynthesis restraining was due to nonstomatal limitation. The declining of LSP and rising of LCP made the available light arrange shortened.(3)The analysis of Chlorophyll fluorescence characteristic showed that as the stress time went on and stress degree increased, the value of Fv/Fm,qP,Yield,ETR in Red-leaf peach and Green-leaf-peach decreased inapprent, while the value of NPQ rose up. (4)The gray relational grade analysis showed that the relationship between climate factors and Pn in Red-leaf peach and Green-leaf-peach was Ta in summer. While the relationship between climate factors and Pn in Red-leaf peach under drought stress were Vp.3 Comparison of the effect on Photosynthetic characteristic of Red-leaf peach under drought stress in summer and autumnComparison of Membrane Permeability,MDA content,Chlcontent,Ant content,antioxidant enzymes(SOD,POD,CAT)activity ,Pn day average value,WUE day average value,Fv/Pm day average value of Red-leaf peach under drought stress in summer and autumn.The results showed that the decrease range of Chl content in Red-leaf peach was higher in summer than in autumn and the ascending range of Ant content in Red-leaf peach is higher in summer than in autumn,so the decrease range of Pn day average value and Fv/Fm day average value was lower than in autumn. By combining with meteorological factors analysis showed that Membrane Permeability,Photosynthetic Apparatus and Photosystemâ…¡of Red-leaf peach under drought stress in summer were damaged lighter than in autumn.
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