【作者】 陈淑芳；

【导师】 朱月林；

【作者基本信息】 南京农业大学 ， 蔬菜学， 2006， 博士

【摘要】 蔬菜设施栽培中，由于不合理的肥料使用、栽培管理措施不当以及雨水淋洗相对较少等原因，造成土壤盐分积累，土壤次生盐渍化现象普遍发生，抑制蔬菜作物生长发育，引起产量和品质下降，严重影响设施蔬菜生产的可持续发展。研究表明，嫁接可以增强蔬菜作物的抗逆性，是克服盐害的一条有效途径。番茄是设施栽培的主要蔬菜之一，近年来关于番茄嫁接技术、嫁接效果鉴定以及抗病性方面进行了一些研究，在嫁接番茄耐盐性有关的生理生化机制研究方面，国内外尚鲜有报道。本试验以营养液培番茄自根苗和嫁接苗为材料，比较NaCl胁迫下自根苗和嫁接苗相关生理生化特性变化。 结果表明，在胁迫前期(2d和5d)，自根苗的Pn、Tr、Ci和Gs显著下降，而Ls显著上升，气孔因素是限制光合作用的主要因子，WUE显著上升，但是以低Pn为代价的，胁迫后期(10d)，自根苗的叶绿素降解加速，盐分离子破坏叶绿体光合结构，Pn、Tr和Gs仍显著下降，Ci显著上升，同时Ls显著下降，Pn下降幅度大于Tr，使WUE显著下降，影响了植株水分利用，非气孔限制成为限制光合作用的主导因子，生长明显受到抑制；嫁接苗在胁迫前期，叶绿素含量变化不显著，光合作用受抑不明显，胁迫后期，气孔因素成为限制光合作用的因子，且整个胁迫期，WUE变化不明显，嫁接苗生长受抑程度较自根苗轻。 在NaCl胁迫下，自根苗和嫁接苗叶片和根系中酶(SOD、POD、CAT和APX)活性和抗氧化剂(AsA和GSH)含量发生明显变化，或被诱导上升，或被抑制下降，但嫁接苗各指标均显著高于自根苗，而丙二醛(MDA)含量显著低于自根苗，表现出较强的抗氧化能力。自根苗和嫁接苗叶片和根系中脯氨酸、可溶性糖、可溶性蛋白质含量在胁迫初期均会被诱导上升，随着胁迫时间的延长，有的持续上升，有的显著下降，但嫁接苗与自根苗相比，不论叶片还是根系中，各指标均显著高于自根苗，渗透调节能力相对较强。 ABA是植物内源激素，多胺是生物体代谢过程中产生的低分子量生物活性物质，它们在植物的生长发育、形态建成以及对逆境的响应方面有重要的作用。NaCl胁迫下，自根苗和嫁接苗ABA含量均表现为先上升后下降，但嫁接苗积累ABA快速，并且在盐胁迫初期表现明显，嫁接苗对盐胁迫有较快的感知性，通过信号转导，快速启动一系列抗逆相关基因的表达，调控植株应答逆境环境。自根苗和嫁接苗叶中多胺总更多还原

【Abstract】 Soil secondary salinization has been a common phenomena in vegetable protected culture, mainly as a consequence of improper fertilizer application, unsuitable culture and management practices, less raining rinse and so on, leading to the progressive accumulation of salts in the soil, which inhibits vegetable growth and development, causes decline of yield and quality, brings a negative effect on sustainable development of vegetable production. It is showed that grafting can improve vegetable tolerance to environmental stresses, become an effective approach to overcome salt stress. Tomato (Lycopersicon esculentum Mill.) is one of the most important vegetables in protected culture, researchs on tomato grafting techniques, identification and the plant’s response to disease and pest attack have been carried out, but few reports on physiological and biochemical mechanisms of grafted tomato in salt stress have been published. We use hydroponically-grown grafted and own-root tomato ( cvs.’ Kagemusya’ and ’ Baoda 903’ as rootstock and scion respectively ) seedlings as experimental materials, comparisons of physiological and biochemical changes were made between grafted and own-root tomato seedlings under 100 mM NaCl stress. There were 4 treatments (own-root, own-root +NaCl, grafted, grafted +NaCl).The following results were obtained. At the early stage of stress (2 d and 5 d), the Pn, Tr, Ci and Gs of own-root plant were significantly decreased, while Ls was significantly increased, the inhibition of photosynthesis of own-root plant was mainly caused by stomatal factor, water use efficiency (WUE) was significantly elevated, resulting from lower Pn. At the late stage of stress (10 d), the chlorophyll degradation of own-root was accelerated, salt ion destroyed chlorophyll photosynthetic structure, the Pn, Tr and Gs of own-root plant were still significantly decreased, Ci was significantly increased, while Ls was significantly decreased, WUE was significantly decreased because the decreasing extent of Pn was more obvious than Tr, leading to a poor water use. Non-stomatal limitation became the main factor to inhibit photosynthesis. Plant growth was significantly inhibited in own-root seedlings. Chlorophyll content was not significantly changed and photosynthesis of grafted plant was not inhibited significantly at the early stage of stress, the inhibition of photosynthesis was mainly caused by stomatal factor at the late stage of stress, and no更多还原