山葡萄应答干旱胁迫的生理生化基础研究

山葡萄（Vitis amurensis Rupr.）应答干旱胁迫的生理生化基础研究

PHYSIOLOGICAL AND BIOCHEMICAL STUDY ON THE RESPONSE　OF AMUR GRAPE (VITIS AMURENSIS RUPR.)TO DROUGHT STRESS

作者：陈　丽　　导师：艾　军　沈育杰

中国农业科学院　　药用植物资源学2011届硕士

摘　要

本研究以葡萄砧木品种“贝达”的当年生扦插苗为对照品种，4个山葡萄品种“双丰”、“双优”、“左山一”、“左山二”的当年生扦插苗为试材，在避雨栽培条件下采用盆栽自然干旱的方法，研究了山葡萄叶片中渗透调节物质、抗氧化酶、内源激素、光合作用及超微结构在应答干旱胁迫过程中的变化。结果如下：

1.　随着干旱胁迫程度的加剧，山葡萄的脯氨酸（Pro）含量升高，可溶性糖含量下降，可溶性蛋白含量先降低后升高。其中“左山一”Pro升高的幅度最大，可溶性糖降低的幅度小于其他几个品种，可溶性蛋白虽然在严重干旱情况下有降低的趋势，但降低不显著。“贝达”Pro和可溶性蛋白始终处于一个较高水平，变化幅度不大，可溶性糖含量在各处理下虽显著降低，但均高于山葡萄。说明干旱胁迫下“左山一”是4个山葡萄品种中渗透调节能力最强的，“贝达”渗透调节能力高于山葡萄。

2.　“贝达”和山葡萄遭遇干旱胁迫时活性氧迸发，膜系统发生膜脂过氧化作用，干旱程度越重，丙二醛累积量越大，“贝达”和“左山一”增加幅度最小。超氧化物歧化酶（SOD）和过氧化物酶（POD）活性先升高后降低，二者协同作用，使山葡萄免遭活性氧损伤，但超过一定限度活性氧清除能力下降。“贝达”的SOD 和POD活性变化幅度不如山葡萄变化幅度大，但SOD始终保持一个较高的活性状态，POD则一直呈升高的趋势，说明植株的抗旱能力不仅和酶活性的变化趋势有关而且和自身酶活性的高低有关。

3.　随着干旱胁迫的加剧，山葡萄叶片中脱落酸和玉米素核苷含量不同程度地升高，赤霉素和生长素含量呈降低趋势，各激素含量的变化和品种关系不大。

4.　干旱胁迫下山葡萄的光和能力降低，蒸腾速率、气孔导度和净光合速率的变化趋势相同，而胞间CO₂浓度先降低后升高。PSⅡ的光性能指数（PIABS）和最大光化学效率降低，其中PIABS对干旱胁迫更加敏感，可作为鉴定抗寒性的指标。“双丰”相对荧光诱导动力学曲线中J点和I点的相对可变荧光值上升，并且出现了明显的K点，说明电子传递的供体侧、受体侧和放氧复合体均受到损伤，此时植株启动自我防御机制，热耗散增加。“左山一”和“贝达”PSⅡ受损伤程度小于“双丰”。

5.　干旱胁迫下山葡萄叶片细胞器受到不同程度的损伤。叶绿体膜溶解断裂，类囊体片层紊乱，空泡化严重，淀粉粒减少，嗜锇颗粒增多且体积变大，发生质壁分离。线粒体的变化滞后于叶绿体，但干旱胁迫严重时会导致线粒体数目增加，线粒体膜变得模糊不清，嵴减少。细胞核趋于扁平，核膜部分断裂，核内物质流出。内质网变短，腔膨大，内质网上附着的核糖体脱落。

关键词　山葡萄　干旱胁迫　生理生化特性　光合作用　超微结构

Abstract

A sheltering cultivation and natural drought experiment was conducted to analyze the changes of osm-regulating substances,antioxidase,endohormones,photosynthesis and ultrastructure in the response to drought stress,by using annual stock shoot of 4 kinds of amur grape cultivars including “Shuangfeng”,“Shuangyou”,“ZuoshanⅠ”and “Zuoshan Ⅱ”as test materials,a grape rootstock variety“Beida”as the control materials. The results were as follows:

1.　The content of proline (Pro)increased and content of soluble sugar decreased with the increasing drought stress in amur grape,while the soluble protein content increased first and then decreased. The content of Pro changed more intensitively and the content of soluble sugar decreased less seriously than other varieties in “Zuoshan Ⅰ”.The soluble protein decreased in “Zuoshan Ⅰ”under seriously drought,but decreased not significantly. The content of proline and soluble protein sustained a high level in “Beida”,without changing seriously. The soluble sugar decreased evidently under different treatments in “Beida”,but it is higher than amur grape. This stated “ZuoshanⅠ” have a great faculty of osmotic-regulation among 4 kinds of amur grape,and the osmotic-regulating faculty of “Beida” is greater than amur grape.

2.　MDA content accreted gradually for broken down by reactive oxygens explosion in “Beida” and amur grape under drought stress,variation amplitude of “Beida” and “ZuoshanⅠ” was less than other varieties. Superoxide dismutase(SOD) and digestible nitrogen(POD) increased firstly and then declined with the increasing drought in amur grape. The two enzymes played a synthetic role in avoiding damage of reactive oxygen species,while the ability of scavenging oxidative radicals decreased when the soil water content less than a certain level. The change of SOD and POD activity in “Beida” is less than amur grape,but the SOD activity is in a high level and the POD activity is in a constantly　increasing tendency. This result indicated resistance ability to drought stress was not only acid and gibberellic declined under drought stress,but there were not a connection between cumulant and variety.

4.　Photosynthesis capacity decreased under drought stress in amur grape. Transpiration rate and stomatal conductance changed in the same trend with net photosynthetic rate,but intercellular gas concentration level increased firstly and then decreased. PSⅡ performance index(PIABS)and maximal photochemical efficiency decreased,PIABS　was more sensitive to drought stress,so we can use it as a drought resistance index. Analysis of JIP-test showed that the J and I steps at fluorescence transient were increased under drought stress,the appearance of the K peak was also observed in “Shuangfeng”. The result showed that donor side,acceptor side and oxygen evolving complex damaged under drought stress. At the same time,amur grape started-up ego defense mechanisms,heat dissipation increased. “Shuangfeng” suffered more than “ZuoshanⅠ”and “Beida”.

5.　The organelles in amur grape leaves were damaged in varying degree under drought stress. The chloroplast membrane dissolved and fragmented,thylakoid lamellas disarranged and vacuolated,starch grain became less,plastoglobulis became more and larger,and plasmolysis occurred. Effect on mitochondrion was later than chloroplast,but severe drought contributed to the appearance of more mitochondrion and less cristae,mitochondrial membrane became unclear. Nucleus inclined to applanation,nucleus membrane dissolved partly,substance in nucleus outflowed. Endoplasmic reticulum became shorter,endoplasmic reticulum tune became intumescentia ,ribosome adherentted to endoplasmic reticulum dropped.

Key words　Amur grape　Drought stress　Physiological and biochemical characteristics　Photosynthesis Ultrastructure