野生大豆对盐胁迫的生理响应机理研究
陈鹏
学位类型博士
导师邵宏波
2013-05-09
学位授予单位中国科学院研究生院
学位授予地点北京
学位专业环境科学
关键词大豆 光合作用 渗透调节 离子平衡 抗氧化系统
其他摘要

目前全球盐渍化土地面积不断扩大,土地盐渍化成为全球性的资源和生态问题。提高作物耐盐性是提高粮食产量和土地利用率的有效手段。本研究选取幼苗期和成熟期的栽培大豆(Glycine max)和野生大豆(Glycine soja)进行梯度盐胁迫处理:050100200300mM NaCl。从生物量、光合生理、渗透调节、离子平衡和抗氧化系统等方面分析和揭示了野生大豆对盐胁迫的生理响应机理。相比于栽培大豆,野生大豆的具有更强的耐盐能力,主要体现在以下几个方面:

1)高盐胁迫条件下,造成野生大豆光合效率降低的主要因素是气孔限制因素。其Rubisco活化酶保持较高的表达水平,Rubisco酶活性显著高于栽培大豆,保证了较高的光合能力。

2)野生大豆的光系统IPS I)和光系统IIPS II)反应中心、PS II供体端和PS II受体端在盐胁迫下能够保持较高的活性,保证了光能的捕获和在电子传递链中的传递效率,对盐胁迫的耐受能力显著高于栽培大豆。

3)当遭受盐胁迫时,细胞内水势降低,会对植物造成生理干旱,严重影响植物的生理功能。野生大豆能够在体内积累更多的脯氨酸、甜菜碱等渗透调节物质来抵御渗透胁迫。

4)在盐渍环境中,大量有害离子进入植物体,野生大豆能够将Na+Cl-等有害离子积累在根系内,减少其向地上部分的运输,从而提高整株植物的耐盐能力。

5)非损伤微测结果表明,野生大豆的根系具有更强的排出Na+Cl-和保留K+的能力,这有利于维持植物体内较高的K+/Na+比和离子平衡,保证正常的生理功能。Na+的外排还与H+的吸收有较好的一致性,提示野生大豆具有较强的Na+/H+反向转运体活性。 

6)盐胁迫条件下,栽培大豆体内的MDA含量显著高于野生大豆,表明栽培大豆遭受到更严重的过氧化伤害。野生大豆在盐胁迫条件下能够显著提高多酚、AsAGSH等抗氧化剂的含量和SODCATAPX等抗氧化酶的活性,表现出更强的抗氧化能力。

; At present, saline lands (especially for agricultural lands) are still expanding with the development of industrialization and urbanization. Soil salinization is becoming a global problem both in resource and ecology areas. Improving salt tolerance of crops is a promising method to increase crop yield and land resource utilization. To investigate the salt tolerance in soybean, seedlings of two varieties of soybean (Glycine max and Glycine soja) were subjected to five salt treatments: 0, 50, 100, 200 and 300mM NaCl. The physiological responses were analyzed from biomass, photosynthesis, osmotic regulation, ion homeostasis and antioxidant system. Compared to cultivated soybean, wild soybean possesses higher salt tolerance due to the following aspects: (1) Stomatal factors are the main causes of the Pn reduction. Higher expression level of Rubisco activase and higher Rubisco activation state in wild soybean ensure the carbon fixation reaction, leading to higher photosynthetic capacity. (2) Under salt stress, wild soybean exhibits higher activity of photosystem reaction center (PS I and PS II) as well as the donor side and acceptor side of PS II. The efficiency of photon absorption and electron transport is significantly higher than that in cultivated soyben.(3) In salinity environment, the intra-cellular water potential decreases, leading to physiological drought. Wild soybean could accumulate more osmoprotectants such as glycine betaine and proline to resist osmotic stress. (4) In salinity environment, the entry and accumulation of toxic ions (mostly Na+ and Cl-) would perturb ion homeostasis. In wild soybean, most of the absorbed Na+ and Cl- are mainly accumulated in the roots to protect the above-ground parts such as photosynthetic leaves. (5) The NMT results showed that wild soybean possessed significantly higher capacity to exclude Na+, Cl- and retain K+ in order to maintain higher K+/Na+ ratio and ion homeostasis. Enhanced Na+ effluxes and correspondingly increased H+ influxes may indicate higher activities of Na+/H+ antiporters in wild soybean.(6) A significantly greater increase of MDA content in cultivated soybean reflects worse lipid peroxidation. When subjected to salt stress, wild soybean exhibits higher capability to resist oxidative damage by increasing the activities of antioxidants (total phenolics, AsA and GSH et al.) and antioxidant enzymes (SOD, CAT, APX et al.).
语种中文
文献类型学位论文
条目标识符http://ir.yic.ac.cn/handle/133337/6724
专题中国科学院烟台海岸带研究所知识产出_学位论文
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陈鹏. 野生大豆对盐胁迫的生理响应机理研究[D]. 北京. 中国科学院研究生院,2013.
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