摘要植物的生长发育易受外界环境的影响，盐胁迫便是其中一个影响因素。活性氧（如超氧阴离子）易在盐胁迫下产生并破坏抗氧化系统的平衡，细胞的结构和功能与活性氧有关，活性氧生产过量质膜会氧化生成丙二醛（MDA），它的含量可以作为测量膜脂过氧化程度强弱的依据。同时细胞膜会在盐胁迫下受到破坏，电解质向外渗透是因为膜的通透性，使植物浸提液的电导率变大，从而生长受抑制甘薯幼苗对环境较敏感，易受到胁迫影响。所以研究盐胁迫对甘薯的影响以及提高甘薯耐盐特性的研究显得越来越重要。褪黑素是广泛存在于植物体内且对植物生长和发育方面有着显著的作用的一类新型激素。69848

本实验研究不同浓度（100、10、5、1、0.5、0.1μM）褪黑素对甘薯幼苗耐盐能力的影响，主要通过测定三个常规伤害指标：MDA（丙二醛含量）、电导率、超氧阴离子来评价褪黑素对甘薯盐胁迫的缓解作用。研究发现，不同浓度褪黑素处理后，徐薯32在褪黑素浓度为0.1μM下耐盐能力有显著的提高，表现为盐胁迫下MDA，电导率，超氧阴离子含量相对较低，处理效果好。本实验确定了褪黑素提高甘薯幼苗耐盐能力的最适使用浓度，为后续研究其生理与分子机制奠定了基础。 

    该论文有图5幅，参考文献17篇

毕业论文关键词：褪黑;  甘薯;  MDA（丙二醛）;  电导率;  超氧阴离子

Effects of exogenous melatonin on salt tolerance of Sweet potato seedlings

Abstract

The growth and development of plants are easy to be affected by the external environment, and the salt stress is one of the influencing factors. Reactive oxygen species such as superoxide anion easily under salt stress produce destroy the balance of antioxidant systems and on cell structure and function and active oxygen, reactive oxygen species production in excess of plasma membrane will oxidize malondialdehyde (MDA), its content can be as a measure of membrane lipid oxi.Salt stress will damages plant cell membrane and lead to the increased electrolyte leakge.The growth inhibition of sweet potato seedlings are more sensitive to the environment and vulnerable to salt stress. Melatonin is a novel plant hormone and plays important role in plant development and stress tolerance. In this study, we investigated the effects of different concentrations of melatonin (100, 10, 5, 0.5, 1, 0.1 μM) on the salt tolerance in sweet potato seedlings.   Our results showed that pretreatment of 0.1 μ M melatonin significantly decreased the MDA, electrolyte leakage rate and superoxide anion contents under salinity stress condition, suggesting this concentration of melatonin can enhance salt tolerance in sweet potato seedlings efficiently. Our results revealed the optimal concentration of melatonin and is useful to the further investigation.  

Key words: Melatonin;  sweet potato;  MDA;  Electrolyte leakage rate;  superoxide anion

目录

摘要 I

Abstract II

目录 3

1 绪论 3

2 材料与方法： 5

2.1 材料： 5

2.2 方法： 5

3 图表与结果： 7

3.1 图表统计 7

3.2 结果： 10

4 讨论： 12

参考文献 13

致谢: