【作者】 张化生；

【导师】 郭晓冬；

【作者基本信息】 甘肃农业大学 ， 蔬菜学， 2007， 硕士

【摘要】 在植物体中,钙是一种必需营养元素。钙具有防止膜损伤和渗漏的作用,在维护细胞壁、细胞膜的结构和功能中起着重要作用,同时作为细胞内第二信使对于提高植物的抗逆性也具有重要作用,其作用的中心环节是细胞内Ca²⁺水平的变化。自从1976年钙调蛋白（CaM）被发现以来,Ca²⁺与其重要受体蛋白CaM构成的钙信使系统在植物感受逆境信号中所起的作用已日益引起人们的重视。但是Ca²⁺在植物抗寒中的作用机制仍不清楚,还存在许多未知领域有待研究。辣椒（Capsicum annuum L）原产于中南美洲热带地区,是人们广为喜爱的喜温蔬菜。因其可作为冬春设施栽培的主要作物,近年来在我国的栽培面积不断扩大。辣椒生长适宜温度为20℃～30℃,低于15℃时生长发育完全停止,持续低于12℃时可能受害,低于5℃则植株完全死亡,故低温是辣椒栽培中的主要限制因素之一。因此,提高辣椒苗抗低温能力就成为理论研究和生产实践上急待解决的问题,对辣椒苗进行抗寒生理研究及化学调控的研究在理论和实践上都具有重要意义。本试验以低温敏感作物--辣椒幼苗为试材,研究了Ca²⁺和钙调素拮抗剂对辣椒幼苗抗冷性的影响。主要结论如下:1.适量的Ca²⁺（10mmol/L）供应能有效提高辣椒幼苗叶片超氧化物歧化酶（SOD）、过氧化物酶（POD）的活性,使之维持在较高的水平上,并降低丙二醛（MDA）含量和细胞膜透性;此外,外源Ca²⁺还增强了辣椒幼苗的根系活力。表明10mmol/L的外源Ca²⁺供应能提高辣椒抗冷性,因为其增强了植株的活性氧清除能力以及对细胞膜的稳定作用。2.外源10mmol/L Ca²⁺能明显地增加低温胁迫下辣椒幼苗叶片可溶性蛋白质、可溶性糖和脯氨酸含量。采用Ca²⁺螯合剂EGTA或钙调素拮抗剂W7对辣椒幼苗低温处理后,辣椒幼苗叶片中可溶性蛋白质、可溶性糖和脯氨酸含量降低。结果说明Ca²⁺信号系统参与了调节辣椒幼苗抗寒过程中渗透物质的合成。3. Ca（NO3）2浸种处理能显著提高辣椒幼苗叶片在低温胁迫下的保护酶活性、保护性物质的含量,降低电解质渗透率、MDA含量,提高辣椒的抗冷性,其中以Ca（NO3）2浓度40mmol·L-1处理效果最明显。4. W7浸种处理显著提高低温胁迫下辣椒幼苗叶片电解质渗透率和MDA含量,降低SOD、POD活性和可溶性蛋白质含量;而Ca²⁺浸种处理显著降低低温胁迫下叶片电解质渗透率和MDA含量,提高SOD、POD活性和可溶性蛋白质、可溶性糖的含量,说明Ca²⁺·CaM信使系统在辣椒幼苗抗冷调控过程中起着重要的作用。更多还原

【Abstract】 Calcium is an essential nutrition element in the plant. Calcium can prevent injury and leakage of membrane.It play an important role in maintaining cell wall , cell membrane structure and function, as a second messenger within cells for improving the resistance of plants. The central link of its role is the changes of Ca²⁺ level intracellular. The function of calcium messenger system formed by Ca²⁺ and its receptor protein CaM in plants adversity signal feelings was paid much attention Since 1976 Calmodulin （CaM） is found. But mechanism of calcium in the cold resistance of plant is still unclear, and there are still many unknown areas to be studied. Pepper （Capsicum annuum L） originated from tropical regions of Central and South America, it is widely popular temperature-sensitive vegetables. Because it’s major crop of winter cultivation, so it’s cultivated area is expanding in China in recent years. The optimal growing temperature of Pepper is 20°C to 30°C, the growth stopped completely below 15°C. it may suffer consistently below 12°C , even it will dead below 5°C, so low-temperature is a major limiting factor during pepper cultivation. Therefore, raising the pepper seedling cold resistance has become a urgency on theoretical research and practical production. The study of cold resistance and chemical control of Pepper seedlings is of great significance.The low-temperature-sensitive crops -- pepper seedlings were used as material in the test, the effect of calcium and calmodulin antagonist on chilling of pepper seedlings was studied. The results are summarized below:1. Adequate calcium（10mmol/L） supply can improve the activity of superoxide dismutase （SOD）, peroxidase （POD） in pepper seedlings leaves and remain them at a relatively high level. Moreover, reduce content of malondialdehyde （MDA） and membrane permeability. Additionally, the exogenous calcium enhances the root activity of pepper seedlings. This indicates: adequate supply of exogenous calcium（10mmol/L） is one of the reasons that raising Pepper cold resistance ,because it enhances the ability of aliminating active oxygen species （AOS） and maintenance of membrane stability 2. Extraneous calcium（10mmol/L） treatment could markedly increase the content of soluble protein, soluble sugar and proline. Moreover, addition of Ca²⁺ chelating agent EGTA or calmodulin antagonist W7 could markedly decrease the content of soluble protein, soluble sugar and proline. Taken together the above results, it is suggested that Ca²⁺ signal system may be regulated by change of some osmolytes in Pepper under low temperature.3. Seeds soaking with Ca（NO3）2 could increase significantly the activity of protective enzyme and content of protective substance, decrease electrolytic leakage, the content of MAD in pepper seedlings, therefore, improving the ability of cold resistance at low temperature.4. Seed soaking with Ca²⁺ solution obviously decreased the contents of malondialdehyde （MDA） and electrolyte leakage, increased the activities of superoxid dismutase （SOD）, Peroxide enzyme （POD） and the content of soluble protein and soluble sugar of pepper leaves, seed soaking with W7 distinctly enhanced the contents of MDA and electrolyte leakage, reduced the activities of SOD, POD and the content of soluble protein and soluble sugar of pepper seedling leaves under chilling stress, The result suggests that Ca²⁺·CaM messenger system plays an important role in controlling chilling resistance of pepper seedling.更多还原