Different Light Front Of Excentrodendron Hsienmu Seedlings Growth And Photosynthesis

In this study, pot excentrodendron hsienmu (Excentrodendron hsienmu) seedlings as experimental material, set4light gradient (100%NS (natural sunshine),42.7%NS,15.3%NS and5,5%NS), shade half a year later, the observation and measurement of the growth, physiological index and photosynthetic indexes, and the correlation analysis, principal component analysis, value analysis method in comprehensive evaluation of fuzzy membership function and plasticity; analyzes its shade tolerance and shade tolerance mechanism, in order to provide a theoretical basis for its plant arrangement and landscaping. The results show that:(1) effects of different light intensity on the growth index of autumn maple seedlings are different. With the increase of the degree of shade, change trend of seedling height growth, autumn maple seedlings ground diameter growth, leaf area, underground fresh weight, shoot fresh weight, fresh weight of the whole plant, ground dry weight, shoot dry weight, plant dry weight were first increased then decreased, in42.7%NS light reaches the maximum value; and the total root volume, total root length, root surface area, total root number, total root average diameter showed a trend of decreasing.(2) effects of different light on physiological index of autumn maple seedlings are different. With the increasing of shade degree, first increased and then decreased indicators are:the content of soluble sugar, total chlorophyll content, chlorophyll a content, chlorophyll b content. The change trend of decreasing first and then rising index:the cell membrane permeability, malondialdehyde (MDA) content, proline content, catalase (CAT) activity, its are in the42.7%NS light minimum; soluble protein, superoxide dismutase (SOD) activity showed a trend of falling.(3) the different light intensity conditions had significant effects on Pn, Ci, Tr, Gs and WUE diurnal variation of biological. Conditions are respectively5%and15%light transmittance, Xian wood does not appear phenomenon at Pn decreased, moderate shading on the elimination of plant photosynthetic "nap" phenomenon has positive effect. With the strong light excentrodendron hsienmu seedlings in full sun, light transmission rate is15.3%and42.7%conditions, Fv/Fm, Yield and qP changes showed "V" curve. Diurnal variations under different illumination conditions qN, NPQ and ETR were "peak" curve, and with the decrease of light intensity and the decreasing trend.(4)Correlation analysis results showed, CAT, SOD, Ss, Sp, Fp between each other and photosynthetic parameters were significantly correlated as clams wood shade of evaluation; principal component analysis, the first principal component corresponds to a larger load values are:NPQ, Tr, Rd, Pn and leaf water content, the second principal component corresponds to a larger load is WUE, soluble protein content, CAT and height. Membership function evaluation obtained42.7%NS,15.3%NS and5.5%NS, respectively0.8544,0.5036,0.4485.Based on the above analysis, excentrodendron hsienmu seedlings of shade tolerance ordering for41.2%NS>15.3%NS>5.5%NS...