摘要：为明确外源褪黑素缓解盐胁迫对番茄种子发芽和幼苗生长不利影响的作用，本试验以1个番茄品种为材料，研究了褪黑素对番茄种子发芽指标的影响；以耐盐和不耐盐的2个番茄品种为材料，研究了褪黑素对番茄幼苗生理指标的影响。结果表明，75 mM NaCl胁迫下，番茄种子发芽势、发芽率、发芽指数显著下降，采用50 μM褪黑素处理，可有效提高种子发芽能力。200 mM NaCl胁迫下，2个品种的番茄幼苗株高、茎粗、全株鲜重、全株干重显著下降，根冠比、H2O2含量、MDA含量和电解质渗透率显著上升，不耐盐品种番茄叶片色素含量显著下降。喷施50 μM褪黑素可使幼苗根冠比达到最大，喷施100 μM褪黑素可以有效增加幼苗株高、茎粗、全株鲜重、全株干重和叶片色素含量，降低H2O2含量、MDA含量和电解质渗透率，缓解盐胁迫带来的伤害。0 mM NaCl条件下，低浓度褪黑素对种子发芽和幼苗生长无显著影响，而高浓度褪黑素发挥抑制作用。25548
毕业论文关键词：番茄；种子；幼苗；褪黑素；盐胁迫
Effects of melatonin in different concentrations on seed germination and seedling growth of tomato under salt stress
Abstract：In order to clarify the effects of exogenous melatonin on the germination and seedling growth of tomato under salt stressIndexes of seed germination and seedling physiological characteristics were studied in three tomato varieties with different drought toleranceThe results showed that under the stress of 75 mM NaCl,seed germination percentage,germination potential and germination index of tomato decreased significantlySoaking the seed in 50 μM melatonin as pretreatment can effectively improve the indexes above Melatonin in high concentrations(100 and 500M) enhanced the damage of salt stressUnder the stress of 200 mM NaCl,the height, stem diameter, fresh weight and dry weight of 2 varieties tomato plants decreased significantly,the root-shoot ratio, content of H2O2 and MDA and electrolyte leakage significantly increasedThe leaf pigment content of the salt-sensitive cultivar decreased significantly Spraying 50 μM exogenous melatonin could maximize the root-shoot ratioSpraying 100 μM exogenous melatonin could effectively increase the height of plants, stem diameter,fresh weight and dry weight of whole plant, content of leaf pigment,reduce the content of H2O2,MDA and electrolyte leakage,alleviate the damage caused by salt stressAnd melatonin in high concentrations（200,500μM）will enhance the damage caused by salt stressUnder the condition of 0 mM NaCl,melatonin in low concentrations have no significant effect on the germination or seedling growth,but melatonin in high concentrations have inhibition effects
Key words: Tomato；Seed；Seedling；Melatonin；Salt Stress     
目  录

摘要1
关键词1
Abstract1
Key words1
引言2
1材料与方法2
11试验材料 2
12试验设计和处理方法   2
121种子发芽试验2
122幼苗生长试验3
13 测定项目与方法 3
131 发芽率、发芽势及发芽指数3
132 幼苗生长指标3
133叶绿素含量3
134 H2O2含量  3
135电解质渗透率 3
136丙二醛（MDA）含量4
14 数据处理 4
2结果与分析4
21不同浓度褪黑素对盐胁迫下番茄种子发芽指标的影响4
22 75 mM NaCl和0 mM NaCl条件下褪黑素对番茄种子发芽指标的影响  5
23 不同浓度外源褪黑素对盐胁迫下番茄幼苗生长指标的影响  6
24不同浓度外源褪黑素对盐胁迫下番茄幼苗光合色素含量的影响7
25 不同浓度外源褪黑素对盐胁迫下番茄幼苗过氧化氢含量以及细胞质膜的影响8
3 讨论   9
4 结论   10
5 致谢10
参考文献10 不同浓度褪黑素对盐胁迫下番茄种子发芽及幼苗生理指标的影响:http://www.youerw.com/shengwu/lunwen_19388.html