【作者】 李阳；

【导师】 齐曼·尤努斯；

【作者基本信息】 新疆农业大学 ， 果树学， 2006， 硕士

【摘要】 沙枣(Elaeagnus angustifolia L.)是新疆的一种重要的经济树种,具有较强的干旱适应性。本文选取尖果沙枣(E. oxycarpa Schlecht.)和大果沙枣(E. mooceroftii Wall.ex Schlecht.)一年生幼苗为试材,实验在遮雨棚中盆栽进行,设对照和三个干旱处理,土壤相对含水量分别是70～75%、50～55%、35～40%和15～20%,水分胁迫处理30天。系统研究了水分胁迫下尖果沙枣和大果沙枣的生长、渗透调节、光合特征和保护酶活性的变化,初步探讨了沙枣抗旱性鉴定方法及评价其抗旱性。主要结论如下:1)土壤相对含水量为35～40%和15～20%时,尖果沙枣和大果沙枣的生长明显受到抑制,但仍保持一定的生长和生物量增加,表现株高降低,叶的扩张变小,茎的加粗生长受到抑制,干物重降低,根冠比增加;干旱处理也导致叶片失水,严重时导致叶片失绿。15～20%土壤水分条件下对生长的抑制最为明显,但仍能生长,变化极为缓慢。复水后,则恢复了快速生长,且在一段时间内表现出一定的补偿性生长效应。2)随着水分胁迫的加强,两种沙枣叶片的叶绿素含量和叶绿素a/b值、净光合速率、气孔导度、蒸腾速率和水分利用效率下降。而且水分胁迫导致净光合速率变化由70～75%和50～55%水分梯度的条件下的单峰曲线变为35～40%和15～20%水分梯度的条件下的双峰曲线,而且导致光合速率的降低主要因素也由气孔因素转变成为非气孔因素。3)随着胁迫时间的延长及程度的增加,叶片的脯氨酸、可溶性糖、K+离子含量增加,蛋白质含量减少;叶片MDA含量增加,细胞膜透性增加,细胞膜受到伤害;SOD、POD、CAT活性表现不同的变化趋势,SOD活性先升高后降低,POD和CAT活性则一直升高。4)综合分析表明:尖果沙枣的抗旱能力高于大果沙枣。各抗旱性鉴定指标对抗旱能力的贡献不同,其中株高、叶面积与茎截面积比、生物量、根系长度、脯氨酸含量、可溶性糖含量、叶片相对含水量、净光合速率、蒸腾速率、气孔阻力、渗透率、保护酶活性和丙二醛含量作为沙枣的抗旱性鉴定指标能够更好地评价沙枣的抗旱能力。更多还原

【Abstract】 Elaeagnus angustifolia L. is one kind of important economical tree in Xinjiang Uygur Autonomous Region. It has the strong compatibility to the drought. One-year-olds seedling of E. oxycarpa Schlecht. and E. mooceroftii Wall.ex Schlecht. were used in this experiment as materials .The control and three drought treatment were designed ,the soil relative water content is 70-75%、50-55%、35-40% and 15-20% respectively, water supply was controlled and treated about 30 days by the weight method in potted mulberry under the rainproof awning, to study systemically the changes of the growth, the osmosis adjustment, the photosynthesis characteristic and the protection enzyme activity. And discussed the research measures of drought-tolerant characters and evaluate drought-tolerant ability of Elaeagnus angustifolia L..Main results as follows:1) The growth of E.oxycarpa Schlecht. and E.mooceroftii Wall.ex Schlecht. was restrained when the soil relative water content is 35～40% and 15～20%. Both of them still kept on growing the biomass weight The plant height declined, the leafs expansion changed slightly, the thicking stem was restrained, dry matter and Root-Crown ratio increased, and the leaf relative water content declined and it also lose its original color. And the affect is most obvious under the soil relative water content of 15～20%, they can still grow, but the progress is extremely slowly. They resumed to fast growth after rewatering, moreover displayed the certain compensating growth effect.2) Along with the increasing degree of water stress, leaf chlorophyll content and chlorophyll a/b value, net photosynthetic rate, stomatal resistance,transpiration rate and water use efficiency of E. oxycarpa Schlecht. and E. mooceroftii Wall.ex Schlecht.were all decreased. Daily change of net photosynthetic rate was a singlepeak curve under the soil relative water content of 70-75% and 50-55%, but it becomes doublepeak curve under the soil relative water content of 35-40% and 15-20%. Moreover the decreased net photosynthetic rate was mainly caused by the stomatal factors under the soil relative water content of 70-75% and 50-55%, and non-factors 35-40% and 15-20%.3) Along with the increasing time and degree of water stress, the leaf’s osmotic adjustment matter, such as soluble sugar content, Proline content and K+ content, increased, soluble protein decreased. the cell membrane systems of leaf of seedling of E.oxycarpa Schlecht. and E. mooceroftii Wall.ex Schlecht. were harmed and the cell membrane penetrability increased, relative electric conductivity and Malondiadehyde content increased. Different treatment suffered differently. Protective enzyme activities showed the variation tendency, Superoxide dismutase activities increased then decreased, Peroxidase, Catalase activities increased all the time of treatment.更多还原