三种豆科草坪草对干旱胁迫的生理响应

发布时间：2018-10-24 13:43

【摘要】：在三大园林植物(树木、花卉、草坪)之中,草坪所占面积位居第一,其日常生长需要大量的水资源进行维护。如何在淡水资源不足的情况下,利用有限的淡水资源高效地进行园林绿化的最大化,这是国内外学者亟需解决的一个重要课题。为探讨草坪草抗旱性差异的生理基础,为草坪草的引种驯化、抗旱草种的选择和截疆管理提供参考。本研究以白三叶(‘海发’白三叶,Trifolium repens L. cv.'Haifa')、天蓝苜蓿(‘陇东’天蓝苜蓿,Medicago lupulina L. cv.'Longdong')、紫花苜蓿(‘同引苜蓿1号’,Medicago sativa L.)为材料,进行了在其种子萌发过程中对脱落酸(Abscisic Acid, ABA)的响应,以及现蕾期干旱胁迫和复水对其形态生长、光合特性、抗氧化保护系统的能力、渗透调节物质的变化等得影响研究,并对其抗旱能力进行了综合评价。主要研究结论如下：(1)外源ABA浓度对白三叶、天蓝苜蓿、紫花苜蓿的种子萌发及幼苗生长具有一定的影响。随着ABA浓度的增高,白三叶、天蓝苜蓿、紫花苜蓿的发芽势、发芽率、株高、发芽指数、活力指数呈现升高的趋势,而根长和畸苗率呈现先升高后降低的趋势,说明ABA抑制了种子的萌发,其相应干旱胁迫的信号转导有可能是ABA依赖途径。天蓝苜蓿对ABA处理表现出较好的萌发响应,其发芽势、发芽率、发芽指数、活力指数、根冠比均明显高于白三叶和紫花苜蓿,畸苗率低于白三叶且与紫花苜蓿无显著差异。(2)在干旱胁迫的条件下,三种豆科草坪草的叶片相对含水量(RWC)呈下降趋势,地下部分和地上部分的干重下降,平均叶面积减少；随着干旱加深,光合作用受到影响,净光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)、色素呈下降趋势,胞间CO2浓度(Ci)呈现先下降后上升的趋势：随着干旱加深,超氧化物歧化酶(Superoxide dismutase, SOD)活性呈下降趋势(天蓝苜蓿除外),过氧化物酶(Peroxidase, POD)活性则呈现上升趋势；丙二醛(Malondialdehyde, MDA)的含量增加,细胞膜膜透性增大。(3)干旱胁迫后复水,植株形态特征恢复正常生长趋势；Pn、Tr、Gs上升,Ci下降,叶片色素含量出现了上升；植物苗的生长环境得到了改善,SOD、POD活性在复水后出现了下降,H202含量虽然增加,但是MDA含量降低；细胞膜的透性减小,脯氨酸(Proline, Pro)含量降低,可溶性蛋白(Soluble protein, SP)含量升高。(4)综合来看,在三种草坪草中,紫花苜蓿的抗旱性最强,白三叶次之,天蓝苜蓿较差。干旱条件下,紫花苜蓿的表现为：株高、叶面积、RWC及叶片色素含量没有显著降低,根长显著升高,抗氧化酶活性增加。(5)四川地区推荐选用草种为天蓝苜蓿。
[Abstract]:Among the three garden plants (trees, flowers and lawns), lawn occupies the first place, and its daily growth needs a lot of water resources to maintain. How to make use of the limited fresh water resources to maximize the landscaping efficiently is an important subject that the domestic and foreign scholars urgently need to solve under the condition of the shortage of fresh water resources. In order to study the physiological basis of drought resistance difference of lawn grass, and provide reference for introduction and domestication of lawn grass, selection of drought-resistant grass species and management of drought resistance grass in Xinjiang. In this study, white clover ('Haifa' white clover, Trifolium repens L. cv.'Haifa'), Tianlan alfalfa ('Longdong' Tianlan alfalfa, Medicago lupulina L. cv.'Longdong') and alfalfa ('coinductive alfalfa 1', Medicago sativa L.) were used in this study. The responses to abscisic acid (Abscisic Acid, ABA) during seed germination, and the ability of drought stress and rehydration in bud stage to its morphological growth, photosynthetic characteristics and antioxidant protective system were studied. The influence of osmotic regulator was studied, and its drought resistance was evaluated. The main conclusions are as follows: (1) exogenous ABA concentration has a certain effect on seed germination and seedling growth of white clover, alfalfa and alfalfa. With the increase of ABA concentration, the germination potential, germination rate, plant height, germination index and vigor index of white clover, alfalfa and alfalfa showed an increasing trend, while the root length and the rate of abnormal seedling increased first and then decreased. The results indicated that ABA inhibited seed germination and the signal transduction of drought stress might be ABA dependent pathway. The germinating potential, germination rate, germination index, vigor index, root-shoot ratio of alfalfa treated with ABA were higher than those of white clover and alfalfa. (2) under drought stress, the relative water content (RWC) of the leaves of the three legume turfgrass decreased, the dry weight of the underground part and the aboveground part decreased, and the average leaf area decreased. With the deepening of drought, photosynthesis was affected, net photosynthetic rate (Pn),) transpiration rate (Pn), (Tr), stomatal conductance (Gs),) pigment decreased, intercellular CO2 concentration (Ci) decreased first and then increased. The activity of superoxide dismutase (Superoxide dismutase, SOD) decreased (except for alfalfa), the activity of peroxidase (Peroxidase, POD) increased, the content of malondialdehyde (Malondialdehyde, MDA) increased, the membrane permeability increased. (3) rehydration after drought stress. The morphological characteristics of plants returned to normal growth trend; Pn,Tr,Gs increased, Ci decreased, leaf pigment content increased, the growth environment of plant seedlings was improved, the activity of SOD,POD decreased after rehydration, the content of H202 increased, but the content of MDA decreased. Cell membrane permeability decreased, proline (Proline, Pro) content decreased, and soluble protein (Soluble protein, SP) content increased. (4) in the three turfgrass, alfalfa had the strongest drought resistance, followed by white clover, and clover was poor. Under drought conditions, the plant height, leaf area, RWC and leaf pigment content of alfalfa were not significantly decreased, root length was significantly increased, and antioxidant enzyme activity was increased. (5) Grass species were recommended for alfalfa in Sichuan area.
【学位授予单位】：四川农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S688.4

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