西藏大学硕士学位论文拉萨半干旱河谷5种灌木的抗旱性研究姓名：王立辉申请学位级别：硕士专业：生态学指导教师：罗大庆20100501摘 要 I摘 要 本研究选取拉萨半干旱河谷 5 个乡土树种：砂生槐(Sophora moorcroftiana)、江孜沙棘(Hippophae gyantsensis)、拉萨小檗(Berberis hemsleyana)、矮锦鸡儿(Caragana maximovicziana)和绢毛蔷薇(Rosa sericea) 为实验材料，通过盆栽控水造成水分胁迫的方法，对其抗旱性生理生化指 标进行了研究，旨在揭示 5 个树种抗旱生理生化响应的差异并综合评价各 树种的抗旱性强弱，为筛选适合西藏半干旱地区的造林绿化树种提供一定 的理论依据。主要结论如下： 1. 在干旱胁迫下，各树种土壤含水量逐渐下降，土壤含水量变化基本 一致，无明显差异（P0.05） ，从而保证了干旱胁迫条件的同一性和各树种 抗旱性差异分析的可靠性。 2. 5 个树种的叶片含水量和相对含水量均随着土壤含水量的降低而下 降，其中绢毛蔷薇下降幅度最大，矮锦鸡儿次之，然后依次是拉萨小檗、 江孜沙棘，砂生槐最小。 3. 随着干旱胁迫的加剧，5 个树种的叶绿素含量也随之下降。到干旱 胁迫后期，从下降幅度来看，绢毛蔷薇叶绿素的下降幅度最大，比对照下 降了 55.73%，其次是矮锦鸡儿(36.54%)、拉萨小檗(32.96%)、江孜沙棘 (27.09%)，最小为砂生槐(19.17%)。 4. 随着干旱胁迫的加剧， 5 个树种的脯氨酸 （Pro） 含量和可溶性糖 （SS） 含量总体均呈增加的趋势。在水分胁迫第 28 天，江孜沙棘、绢毛蔷薇、砂 生槐、 矮锦鸡儿和拉萨小檗 Pro 含量分别比对照增加了 3.5、 2.8、 1.1、 1.3 和 3.4 倍；在干旱胁迫初期，各树种可溶性糖（SS）含量增长缓慢，但在 胁迫处理的第 28 天时，与对照相比，各树种可溶性糖含量也均有较大幅度 的增长，其中拉萨小檗比对照增加了 210.86%，增幅最大，其次是砂生槐 (125%)、江孜沙棘(88.23%)、绢毛蔷薇(77.92%)和矮锦鸡儿(43.18%)。 5. 随着干旱胁迫的加剧，各树种细胞膜系统受到伤害的程度也加剧， 体现在 5 个树种相对电导率和丙二醛（MDA）含量的增加。与各树种的对照 相比，相对电导率增加幅度最大的是绢毛蔷薇，其次是矮锦鸡儿、拉萨小 檗和江孜沙棘，砂生槐的相对电导率增幅最小。砂生槐 MDA 含量增幅最小， 仅比对照增加 29.15%，然后依次为拉萨小檗、江孜沙棘、矮锦鸡儿，绢毛 蔷薇膜脂过氧化作用最剧烈，MDA 含量增幅最大。 西藏大学农牧学院硕士学位论文 II6. 随着干旱胁迫的加剧,各树种的 SOD、POD 和 CAT 活性总体都呈现出 先升后降的变化趋势。干旱胁迫 1-7 天，各树种的 SOD、CAT、POD 活性都 呈上升趋势；干旱胁迫第 7 天，绢毛蔷薇的 SOD、CAT、POD 活性达到最高 值，随后下降；干旱胁迫第 14 天，江孜沙棘、矮锦鸡儿和拉萨小檗 3 个树 种的 SOD、CAT、POD 活性达到最高值，随后下降；砂生槐的 SOD 和 POD 活 性在处理第 21 天才达到最高，随后下降，而砂生槐的 CAT 活性则一直保持 了上升趋势。 7. 对 5 个树种 10 项生理生化指标进行主成分分析表明， 叶片含水量、 相对含水量、超氧化物歧化酶、丙二醛含量、可溶性糖含量、过氧化物酶、 叶绿素含量和相对电导率 8 个指标是评价各树种抗旱能力大小最主要的指 标。 8. 运用模糊数学的隶属（反隶属）函数法对 5 个树种的抗旱性进行综 合评价，其抗旱能力大小排序为：砂生槐拉萨小檗江孜沙棘矮锦鸡儿 绢毛蔷薇。 关键词：灌木，抗旱性，干旱胁迫，生理生化指标，综合评价 ABSTRACT IIIABSTRACT Five native species in semi-arid valley of Lhasa River: Sophora moorcroftiana, Hippophae gyantsensis, Berberis hemsleyana ， Caragana maximovicziana and Rosa sericea were selected for the experimental materials, drought-resistant physiological and biochemical index of them were studied under different content of soil water in pot in order to reveals the differences between the five species in physiological and biochemical responses and evaluate the drought resistance of them, which provide a theoretical basis for selecting afforestation tree species suitable for semi-arid regions in Tibet. The main conclusions are as follows: 1. Under drought stress, the soil moisture of each species gradually decreased, various tree species suffered basically the consistent intensity of drought stress, and there is no significant difference(P0.05), thus ensuring that the identity of the drought conditions and the reliable analysis of differences in various tree species. 2. Leaf water content and relative water content of five species decreased with the decline of soil water content, which Rosa sericea the biggestdrop, followed by Caragana maximovicziana, Berberis hemsleyana, Hippophae gyantsensis and Sophora moorcroftiana. 3. Chlorophyll content of five species also decreased. To the later stage of drought stress, chlorophyll of Rosa sericea decline 55.73% compared with the CK, followed by Caragana maximovicziana(36.54%), Berberis hemsleyana(32.96%), Hippophae gyantsensis(27.09%), and Sophora moorcroftiana is the minimum(19.17%). 4. The proline content and soluble sugar content of five species showed an upward trend overall. On the 28th day of drought stress, Hippophae gyantsensis, Rosa sericea, Sophora moorcroftiana, Caragana maximovicziana and Berberis hemsleyana Pro content increased 3.5, 2.8, 1.1, 1.3 and 3.4 times; the soluble sugar content of five species increased slowly, but the soluble sugar content of each species have higher growth on the 28th day of drought stress compared with the CK. Berberis hemsleyana increased 210.86% compared with the CK, followed by Sophora moorcroftiana (125%), Hippophae gyantsensis(88.23%), 西藏大学农牧学院硕士学位论文 IVRosa sericea(77.92%) and Caragana maximovicziana (43.18%). 5. The injury degree of five species membrane system increased, reflected in the five species increase of relative conductivity and malondialdehyde content. Compared with the CK of various species, the largest relative conductivity rate increase is Rosa sericea, followed by Caragana maximovicziana, Berberis hemsleyana and Hippophae gyantsensis, Sophora moorcroftiana has smallest increase in the relative conductivity. MDA content of Sophora moorcroftiana has the smallest increase, only 29.15% increase compared with the CK, then followed by Berberis hemsleyana, Hippophae gyantsensis, Caragana maximovicziana, the most intense peroxidation and the largest MDA content is Rosasericea. 6. The overall trend of SOD, POD and CAT activity of five species emerged first, and then decreased. 1-7days of drought stress, the SOD, CAT, POD activity of each species was in an uptrend; the SOD, CAT, POD activity of Rosa sericea reached the climax on the 7th day of drought stress, then decreased; on the 14th days of drought stress, the SOD, CAT, POD activity of Hippophae gyantsensis, Caragan