【作者】 朱进；

【导师】 别之龙；

【作者基本信息】 华中农业大学 ， 设施园艺， 2008， 博士

【摘要】 随着设施栽培的快速发展,设施内土壤次生盐渍化日趋严重,已成为限制设施栽培发展的主要障碍。黄瓜是设施内栽培的主要蔬菜之一,其耐盐性较弱,采用嫁接可显著提高黄瓜的耐盐性,但对嫁接提高黄瓜耐盐性的生理机制尚不明晰。本试验对不同基因型的黄瓜和嫁接砧木的耐盐性进行了鉴定,研究了不同接穗和砧木耐盐性差异的生理机制,在此基础上研究了不同砧/穗关系对黄瓜嫁接苗耐盐性的影响及其生理作用机制,以期为阐明嫁接提高黄瓜耐盐性提供理论依据,为指导黄瓜的嫁接栽培提供参考。本研究主要结果如下:采用聚类分析对20个黄瓜品种和22个嫁接砧木的耐盐性进行了鉴定。结果表明,20个黄瓜品种中,‘早多佳’、‘华早2号’、‘中农8号’、‘津育1号’、‘津优3号’为耐盐性强的黄瓜品种,‘津冠1号’、‘许优1号’、‘津春5号’、‘津春4号’、‘东方明珠’、‘湘早3号’、‘特早1号’、‘津优1号’为中等耐盐黄瓜品种,‘白皮黄瓜’、‘宁丰8号’、‘美农4号’、‘津春3号’、‘津杂4号’、‘津杂2号’、‘津春2号’为耐盐性弱的黄瓜品种:22个嫁接砧木中,可分为二大类,其中,‘春白玉’西葫芦、‘早青一代’西葫芦、‘铁将军F1’南瓜、‘极早秀玉’西葫芦为耐盐性弱的品种,其它为耐盐性强的品种。耐盐性强的砧木品种可分为3个亚类,‘孝感瓠瓜’、‘同心瓠瓜’、‘汉龙碧玉’瓠瓜和‘超丰8848’瓠瓜耐盐性很强,‘黑籽南瓜’耐盐性强,其它13个品种耐盐性较强。在黄瓜种子萌发期和嫁接砧木苗期可对其耐盐性进行快速鉴定。采用‘早多佳’和‘津春2号’黄瓜品种为试验材料,对不同基因型黄瓜在盐胁迫下的盐害指数、生长及生理特性进行了研究。结果表明,黄瓜根系不具备阻止Na⁺向叶片运输来减轻盐胁迫的生理机制,是黄瓜不耐盐的根本原因。盐胁迫下,Na⁺在黄瓜叶片中大量积累,引起离子毒害,K⁺、Ca²⁺、Mg²⁺含量显著下降,Na⁺/K⁺、Na⁺/Ca²⁺比值显著升高,导致离子失去平衡,尽管盐胁迫下黄瓜的SOD、POD活性显著增加,‘早多佳’品种的脯氨酸显著积累,但黄瓜的质膜透性和MDA含量显著增高,地上部含水量显著下降,遭受的氧化胁迫和渗透胁迫严重,叶绿素含量显著下降、光合速率、蒸腾速率、气孔导度显著降低,生长显著受抑,盐害指数显著增大,但对光系统Ⅱ无显著影响。相比较而言,‘早多佳’遭受的盐害、生长受抑制程度较‘津春2号’轻。叶片中较低的Na⁺含量、Na⁺/K⁺比值、Na⁺/Ca²⁺比值和较高的Ca²⁺含量是‘早多佳’比‘津春2号’耐盐的重要原因。采用‘超丰8848’、‘超级拳王’和‘黑籽南瓜’为试验材料,对不同砧木在盐胁迫下的生长及生理特性进行了研究。结果表明,通过根茎阻止Na⁺向叶片运输,从而使叶片中Na⁺的含量处于较低的水平而使植物减轻离子毒害,是3个砧木耐盐的根本原因。盐胁迫下,3个砧木叶片中Na⁺含量逐渐升高,K⁺、Ca²⁺含量逐渐降低、生长显著受抑,光合速率、蒸腾速率、气孔导度显著降低,地上部含水量逐渐下降,但叶绿素荧光参数无显著变化。盐胁迫下,‘超级拳王’和‘黑籽南瓜’的SOD、POD活性、脯氨酸、MDA含量显著增加,根系活力显著下降,但‘超丰8848’的均无显著变化。相比较而言,‘超丰8848’遭受的渗透胁迫、氧化胁迫最轻,‘黑籽南瓜’遭受的渗透胁迫和氧化胁迫最重,‘超丰8848’较高的气体交换能力,较稳定的根系活力是‘超丰8848’比‘超级拳王’和‘黑籽南瓜’耐盐的重要原因。‘超级拳王’较高的Ca²⁺含量、较低的Na⁺/Ca²⁺比值、较好的光合特性是其比‘黑籽南瓜’耐盐的重要原因。采用‘早多佳’和‘津春2号’黄瓜品种作接穗,耐盐的‘超级拳王’作砧木嫁接,以自根苗为对照,对不同接穗嫁接黄瓜苗在盐胁迫下的生长及生理特性进行了测定。结果表明,盐胁迫下,嫁接苗地上部和根干重、叶面积、茎粗降低的程度显著低于自根苗;嫁接苗叶片和接穗茎中Na⁺含量和Na⁺/K⁺、Na⁺/Ca²⁺比值显著低于自根苗,而砧木茎和根中的Na⁺含量和Na⁺/K⁺、Na⁺/Ca²⁺比值显著高于自根苗;嫁接苗叶片中K⁺含量、可溶性糖含量、地上部含水量、SOD、POD、CAT、APX活性、AsA/DHA的稳定性、光合速率、蒸腾速率、气孔导度显著高于自根苗,MDA含量显著低于自根苗。盐胁迫下,‘早多佳’嫁接苗的茎粗、叶面积减小的程度、叶片中Na⁺含量、Na⁺/K⁺、Na⁺/Ca²⁺比值显著低于津春2号嫁接苗,K⁺、Ca²⁺、Mg²⁺、脯氨酸含量、POD、CAT、APX活性、AsA含量、AsA/DHA的稳定性显著高于津春2号嫁接苗,但光合速率、蒸腾速率、地上部含水量和MDA含量与‘津春2号’嫁接苗的无显著差异。‘早多佳’嫁接苗叶片中较低的Na⁺含量和Na⁺/K⁺、Na⁺/Ca²⁺比值,较高的K⁺、Ca²⁺、Mg²⁺含量,是‘早多佳’嫁接苗比‘津春2号’嫁接苗耐盐的重要原因。采用‘超丰8848’和‘黑籽南瓜’作砧木,‘津春2号’黄瓜作接穗嫁接,以‘津春2号’自根苗为对照,研究了盐胁迫对不同砧木嫁接黄瓜苗生长及生理特性的影响。结果表明,盐胁迫下,嫁接苗地上部和根干重、叶面积、茎粗受抑制的程度显著低于自根苗;嫁接苗叶片中Na⁺、MDA、H₂O₂含量、超氧阴离子产生速率、Na⁺/K⁺和Na⁺/Ca²⁺比值显著低于自根苗,而叶片中K⁺含量、可溶性糖含量、地上部含水量、SOD、POD、CAT、APX活性、AsA/DHA的稳定性、光合速率、蒸腾速率、气孔导度显著高于自根苗;嫁接苗的胞间CO₂浓度显著下降,自根苗的则显著上升。盐胁迫下,‘超丰8848’嫁接苗生长受抑制程度、叶片中的Na⁺/k⁺比值、MDA、H₂O₂含量显著低于‘黑籽南瓜’嫁接苗,脯氨酸含量、可溶性蛋白质含量、地上部含水量、SOD、POD、CAT、APX、GR活性、光合速率、蒸腾速率和气孔导度显著高于‘黑籽南瓜’嫁接苗,因此,耐盐性显著强于‘黑籽南瓜’嫁接苗。通过根茎限制Na⁺向叶片运输来减轻盐胁迫,是嫁接提高黄瓜耐盐性的主要生理机制。无论是采用不同接穗嫁接还是采用不同砧木嫁接,限制Na⁺向地上部运输的部位主要是砧木的根和茎,砧木在提高黄瓜耐盐性的作用中远大于接穗。更多还原

【Abstract】 With the development of protected culture,soil secondary salinization has been more and more severe and has become the biggest obstacle of limiting the development of protected culture.Cucumber（Cucumis sativus L.） is one of the most important vegetables in protected culture which is salt sensitive.It is showed that grafting can improve cucumber tolerance to salt stress,though the physiological mechanism is not known.In our study,the cultivars with different salt sensitivity were evaluated from a great deal of cucumbers and rootstocks,and the physiological mechanism of different cucumbers and rootstocks to salt stress was determined.Basis am it,the effects and physiological mechanism of the connection of rootstock and scion on the salt tolerance of grafted cucumber plants were studied which supply theoretic basis for clarify grafting enhance salt tolerance of cucumber and reference for directing the grafted culture of cucumber. The main results in the present study are presented as follows:Salt resistance of 20 cucumber cultivars and 22 species of rootstocks were evaluated by using the cluster analysis.The results showed that:Among 20 cucumber cultivars, ’Zaoduojia’,’Huazao No.2’,’Zhongnong No.8’,’Jinyu No.1’ and ’Jinyou No.3’ held high resistance to salt stress,whereas ’Jinguan No.1’,’Xuyou No.1’,’Jinchun No.5’,’Jinchun No.4’,’Dongfangmingzhu’,’Xiangzao No.3’,’Tezao No.1’ and ’Jinyou No.1’ were moderately salt tolerant,but ’Baipihuanggua’,’Ningfeng No.8’,’Meinong No.4’, ’Jinchun No.3’,’Jinza No.4’,’Jinza No.2’ and ’Jinchun No.2’ cucumber cultivars were sensitive to salt stress.Among 22 species of rootstocks,the rootstocks could be clustered to two groups,Cucurbit pepo L.cv.’Chunbaiyu’,’Zaoqingyidai’ and ’Jizao xiuyu’,and Cucurbita moschata Duch.cv.’Tiejiangjun F₁’ were sensitive to salt stress whereas the other species of rootstocks were tolerant to salt stress,and salt resistant rootstocks could be clustered to three subgroups,Lagenaria siceraria Standl.var.clavata Makino cv. ’Xiaoganhugua’,’Tongxinhugua’,’Hanlongbiyu’ and ’Chaofeng8848’ showed the highest salt resistance,Cucurbit ficifolia cv.’Heizinangua’ exhibited tolerant,whereas the other thirteen species showed more salt resistance.The salt resistance of cucumbers and rootstocks could be screened at germination stage and seedling stage,respectively.The effects of NaCl stress on the salt injury index,plant growth and physiological trait of different cucumbers were investigated by using ’Zaoduojia’ and ’Jinchun No.2’ as the test materials.The results showed that:The cucumber roots have not the mechanism of limiting the translocation of Na⁺ to leaf to alleviate salt stress.It is the essential cause that cucumber makes salt sensitive.Na⁺ accumulated in the leaf and cause ion toxicity,the content of K⁺,Ca²⁺,Mg²⁺ in leaf decreased markedly,Na⁺/K⁺ ratio and Na⁺/Ca²⁺ ratio of both cultivars increased significantly resulted in ion unbalance with increasing concentrations of NaCl.Despite the SOD and POD activities of both cultivars increased significantly and the free proline content of ’Zaoduojia’ increased markedly,the membrane permeability,MDA content and the salt injury index increased markedly,and the shoot water content decreased significantly resulting in severe oxidation and osmotic stress.The chlorophyll content and photosynthetic rate decreased significantly,plant growth was restrained,but Fo、Fv/Fm、F PSⅡand qP of both cultivars was unaffected by salt stress.’Zaoduojia’ exhibits a better protection mechanism against oxidative damage and lipid peroxidation by maintaining lower Na⁺ content,Na⁺/K⁺ ratio,Na⁺/Ca²⁺ ratio and higher Ca²⁺ content in leaf than salt sensitive cv.’Jinchun No.2’.The effects of NaCl stress on the plant growth and physiological trait of different rootstocks were investigated by using ’Chaofeng 8848’,’Chaojiquanwang’ and ’Heizinangua’ as the tested materials.The results showed that:It is essential that salt tolerance can be obtained by three rootstocks for limiting the translocation of Na⁺ from the root and stem to the leaf,making the lower Na⁺ content in the leaf to alleviate ion injury.The contents of Na⁺ in the leaf of three rootstocks were unaffected by at 50 mmol/L NaCl and increased significantly at 100 and 150 mmol/L NaCl.The K⁺,Ca²⁺ and shoot water content was gradually decreased under salt stress.The photosynthetic rate, transpiration rate,stomatal conductance of three rootstocks decreased markedly and plant growth was restrained with increasing concentrations of NaCl,but Fo,Fv/Fm,F PSⅡ,qP of three rootstocks were unaffected by salt stress.The proline content,MDA content, SOD and POD activities of Chaojiquanwang and ’Heizinangua’ increased,the root activity was decreased significantly,whereas those of ’Chaofeng 8848’ were unaffected under salt stress.The degree of oxidation stress and osmotic stress of ’Chaofeng 8848’ sufferred was the slightest whereas that of ’Heizinangua’ was the most severe.’Chaofeng 8848’ exhibits a better protection mechanism against salt stress by maintaining higher photosynthetic rate ability and root activity than ’Chaojiquanwang’ and ’Heizinangua’. ’Chaojiquanwang’ exhibits a better protection mechanism against salt stress by maintaining lower Na⁺/Ca²⁺ ratio,higher Ca²⁺ content in the leaf and photosynthetic ability than ’Heizinangua’.The ungrafted cucumber plants used as controls,the effects of grafting with different scions on cucumber growth and physiological trait were investigated by using ’Zaoduojia’ and ’Jinchun No.2’ as scion,and ’Chaojiquanwang’ as rootstock under NaCl stress.The results showed that:Under NaCl stress,the reductions in the shoot and root dry weight, leaf area,stem diameter of grafted plant（?） were lower than those of ungrafted plants.The Na⁺ content,Na⁺/K⁺ ratio,Na⁺/Ca²⁺ ratio in the leaf and scion stem of grafted plants were lower whereas those of in the rootstock stem a（?）d root were higher than in ungrafted plants. The K⁺ contents,soluble sugar contents,shoot water contents,SOD,POD,CAT,APX activity,the stability of AsA/DHA,Photosynthetic rate,transpiration rate and stomatal conductance were higher,whereas the MDA contents in the leaf of grafted plants were lower than that in ungrafted plants.The reductions in leaf area and stem diameter of grafted ’Jinchun No.2’ plants were more severe than those of grafted ’Zaoduojia’ ones. The Na⁺ contents and Na⁺/K⁺,Na⁺/Ca²⁺ ratio in leaf were lower whereas K⁺,Ca²⁺,Mg²⁺, AsA and proline contents,POD,CAT,APX activities,the stability of AsA/DHA in leaves of grafted ’Zaoduojia’ plants were higher than those of grafted ’Jinchun No.2’ plants under the same NaCl stress.However,the shoot water content,MDA content, Photosynthetic rate,transpiration rate and stomatal conductance were not different between the grafted ’Zaoduojia’ plants and the grafted Jinchun No.2 ones under salt stress.Grafted ’Zaoduojia’ plants exhibit a higher salt tolerance by maintaining lower Na⁺ content,Na⁺/K⁺,Na⁺/Ca²⁺ and higher k⁺,Ca²⁺ and Mg²⁺ contents than grafted ’Jinchun No.2’ ones.But grafting reduces the difference of salt tolerance between ’Zaoduojia’ and ’Jinchun No.2’.The Ungrafted cucumber plants used as controls,the effects of grafting with different rootstocks on cucumber growth and physiological trait were investigated by using ’Chaofeng 8848’ and ’Heizinangna’ as rootstocks,’Jinchun No.2’ as scion under NaCl stress.The results showed that:The reductions in the shoot and root dry weights, leaf area,stern diameter of grafted plants were lower than those of ungrafted plants under the same NaCl stress.Na⁺,MDA,H₂O₂ contents,O₂^- producing rate,Na⁺/K⁺ ratio, Na⁺/Ca²⁺ ratio were lower,whereas K⁺,solube sugar,shoot water content,SOD,POD, CAT,APX activity,the stability of AsA/DHA,Photosynthetic rate,transpiration rate and stomatal conductance in the leaf of grafted plants were higher than those of ungrafted plants at the same NaCl stress.Intercellular CO₂ concentration of grafted plants decreased whereas that of ungrafted plants increased significantly under salt stress.The reductions in shoot and root dry weight,leaf area and stem diameter of grafted ’Chaofeng 8848’ plants were significantly lower than those of grafted ’Heizinangua’ plants ones.MDA, H₂O₂ contents and Na⁺/K⁺ ratio were lower whereas proline contents,soluble protein content,SOD,POD,CAT,APX,GR activities,Photosynthetic rate,transpiration rate and stomatal conductance in leaves of grafted ’Chaofeng 8848’ plants were higher than those of grafted ’Heizinangua’ plants under the same NaCl stress.Therefore Then,the salt tolerance of grafted ’Chaofeng 8848’ plants is higher than those of ungrafled ’Heizinangua’ plants ones.It is the most possible physiological mechanism of grafting improves the salt tolerance of cucumber through root and stem limiting the translocation of Na⁺ to the leaf to alleviate salt damage.Whether grafting either using different scions or different rootstocks,the parts of limiting the translocation of Na⁺ to the shoot were mostly the stem and root of the rootstock,the effects of the rootstocks were are bigger than the scion on improving the salt tolerance of cucumber.更多还原