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通过盆栽控水实验,模拟科尔沁沙地由东至西50年的年均降水量及最大、最小年降水量下的土壤水势,分析了不同水分处理(土壤水势分别为-16.18、-5.09和-4.50bars,即A、B和C处理)对樟子松2年生幼苗膜脂过氧化产物[丙二醛(MDA)、脂膜相对透性(RC)和超氧阴离子自由基(O2.-)产生速率]、渗透调节物质[可溶性糖(SS)、可溶性蛋白(SP)和脯氨酸(Pro)]和膜保护酶(SOD酶和POD酶)的影响。不同水分处理对樟子松幼苗针叶内的保护酶、渗透调节物质及膜脂过氧化的作用影响显著。随着土壤水势的降低,幼苗的SOD酶呈现微下降再升高的趋势;POD酶活性呈逐渐升高的趋势;幼苗的渗透调节物质(SS、SP和Pro)的含量均呈现上升趋势;3种水分处理的可溶性糖和可溶性蛋白含量上升的幅度最大,A处理分别是C处理的1.8倍和2.4倍,脯氨酸的含量持续积累;随干旱胁迫加重,MDA、RC和O2.-产生速率均有明显上升趋势,以O2.-产生速率上升幅度最大。这表明,樟子松幼苗通过体内的生理生化机制,尤其是增加渗透调节物质的含量,实现对干旱胁迫较强的忍耐性和较好的适应性。A处理针叶内的自由基大量积累和膜脂过氧化程度加重,对植物造成不可逆的损伤。
The effects of different water treatments (soil water potentials -16.18, -5.09 and -16.18, respectively) were analyzed through the pot experiment of water control to simulate the average annual precipitation of Horqin sandy land from east to west in 50 years and the maximum and minimum annual rainfall. 4.50 bars, ie treatments A, B and C) on the lipid peroxidation products (MDA, lipid permembrane relative permeability (RC) and superoxide anion free radical (O2.-) Production rate], osmolytes [soluble sugar (SS), soluble protein (SP) and proline] and membrane protective enzymes (SOD and POD enzymes). The effects of different water treatments on the protective enzymes, osmotic adjustment substances and membrane lipid peroxidation in coniferous seedlings of Pinus sylvestris var. Mongolica were significant. With the reduction of soil water potential, the SOD enzyme activity of seedlings showed a slight downward trend and then upward trend. The activity of POD enzyme increased gradually. The content of osmotic adjustment substances (SS, SP and Pro) of seedlings showed an upward trend. 3 The content of soluble sugar and soluble protein in the treatments of water treatment increased the most. The contents of proline in A treatments were 1.8 times and 2.4 times that of C treatments respectively. With the drought stress aggravated, the contents of MDA, RC and O2.- All showed a clear upward trend, with the largest rate of increase of O2.-. This indicates that Pinus sylvestris seedlings achieve stronger tolerance and better adaptability to drought stress through physiological and biochemical mechanisms in vivo, especially increasing osmotic adjustment substance content. A treatment of conidia free radical accumulation and membrane lipid peroxidation increased, causing irreversible damage to plants.