枫香属植物对不同程度干旱胁迫的响应毕业论文(编辑修改稿)

枫香属植物对不同程度干旱胁迫的响应毕业论文(编辑修改稿)内容摘要：

eriment, to research the drought resistance strength of three kinds of maple seedlings, the results are as follows: (1)After 30 days water deficit and recover, no deadth phenomenon, and are appear different degrees of death phenomenon, mortality was %, and mortality was %。 after drought 60 d found that three maple seedlings are different degrees of death phenomenon, mortality was about 18%, China of north American maple with liquidambar and mortality were %, % height growth along decreased with the elongation of drought stress time. with the prolonged drought stress has been on the decrease tendency, in the arid first 18 d reduce tendency obvious, leveling off after 18 d, the overall growth rate is lower than the control kinds of sweet gum seedling biomass with the elongation of drought stress time, the root, stem and leaf, total 枫香属植物对不 同程度干旱胁迫的响应 4 biomass were under lower trend, leaf weight ratio with trend of reduce in the extension of drought stress time, stem weight than up, the root weight ratio first decreases and then increases. It will facilitate the absorption of moisture indry conditions and maintenance of water balance. (2)Shortterm (30 d) drought stress conditions, the actual photosynthetic efficiency of three kinds of sweet gum (Yield), coefficient of photochemical quenching (qP), non cyclic electron transport rate (ETR) in drought around 12 d are reduced in different degrees, NPQ was a slow upward trend. PS Ⅱ potential activity (Fv/F0), maximum quantum yield of photochemical reaction (Fv/Fm) in drought around 24 d began to decrease. and in the short term drought (30 d) and longterm (60 d) drought stress, the Yield, Fv/F0, Fv/Fm, qP, ETR is reduced, NPQ increased, while the each parameter in the shortterm drought (30 d) there were no obvious difference pared with controls, processing after 60 d pared with the control group, the actual photochemical efficiency coefficient (Yield) and photochemical quenching (qP), PSⅡ potential activity (Fv/F0) and photochemical quenching coefficient (qN), non cyclic electron transport rate (ETR) is reduced, the PSⅡ maximum photochemical efficiency (Fv/Fm) remains the maple seedlings leaf pigments absorb light energy dissipating appear abnormal, leading to the condition of dark adaptation the initial fluorescence value increased, the fluorescence emission dissipating energy ratio increased. (3) in short term (30d) under drought condition, leaf SOD activity increased, SOD/CAT value decreased, MDA content decreased, the long drought (60 d) results in the decrease of SOD activity, POD activity increased, SOD/POD, SOD/CAT were decreased pared with control subjects。 in the shortterm drought (30 d), the leaf SOD activity decreased and POD activity increased, SOD, POD, SOD/CAT value decreased, MDA content increased, the CAT has no obvious change, and prolonged drought (60 d), the SOD activity increased, SOD/POD increased value, SOD/CAT value decreased, MDA content decreased. in the shortterm drought (30 d), leaf SOD/POD value rise, MDA content increased, the long drought (60 d), SOD and POD activity showed different amplitude reduced, SOD/POD value increased. root SOD activity, CAT activity showed a trend of reduce the rise, fall after rise first POD activity, SOD/POD value is reduced, SOD/CAT value increases after the first reduce。 root SOD activity, CAT activity increased after lower first, SOD/POD, SOD, CAT values decrease after rising first, POD value increased。 SOD activity, CAT activity, SOD/POD value first increased and then decreased, POD activity, 枫香属植物对不 同程度干旱胁迫的响应 5 SOD/CAT value decreased, MDA content are rising. Indicated a certain stress level and time, to activate SOD, POD,CAT activity to regulate the stress of their damage. (4)Maple leaf anic carbon content has a slow upward trend with the elongation ofdroughtstress time., but the upward trend is not obvious, leaf N content is increased, there is no consistent change in , leaf nitrogen content decrease after drought 60 d. leaf C/N showed a certain degree of decline, and was showed a rising trend. the root system of anic C, total N and C/N ratio changes with the degree of drought stress, showing obvious differences between the species. (5)Three kinds of sweet gum leaf soluble sugar content, soluble protein content, proline content has the varying degree rise, the root system of anic osmoregulation substances soluble protein and proline content were rising trend, no consistent change in soluble sugar content .Ca2+, Mg2+ content is slightly lower trend, K+ content has a tendency to rise, root peration of inanic ion (Ca2+, K+, Mg2+) levels were slightly rising trend. In the short term, with the extension of drought time, three kinds of maple leaf relative water content (RWC) gradually reduced, water saturation deficit (WSD), anization (TD) in dry density before 12 d, has a rising trend in the late dry, three maple bay leaf water potential increased with the decreasing of soil water content. (6)Three kinds of sweet gum specific root length (SRL), specific surface area (SRA), relative surface area (RSA) all showed a trend of reduce the rise, but longterm drought (60 d) causes specific root length (SRL), specific surface area (SRA), relative surface area (RSA) decreases, and the average diameter (ARD) showed lower before rising trend, with the elongation of drought stress time, the three kinds of sweet gum root activity showed obvious interspecific differences, including fragrance rising along with the prolonged drought, root activity, and were the extension of drought stress time, root activity has been in a downward trend, root relative electrical conductivity and root cap ratio increases. It demonstrated that shortterm drought promotes liquidambar seedling root growth, longterm droughts inhi。