【作者】 郭永清；

【导师】 沈永宝；

【作者基本信息】 南京林业大学 ， 森林培育学， 2004， 硕士

【摘要】 林木种子休眠是植物长期适应外界环境以保持物种不断延续和进化而形成的一种生理生态特性。其有利于植物个体的生存和发展，但也给种子检验和林业生产带来了一定的不利和困难。因此，研究种子休眠特性和解除休眠的方法便成为种子研究领域重要的任务之一。本文以北美鹅掌楸（liriodendron tulipifera L）种子为材料，通过对种皮透水性测定、外种皮抑制物质的提取与生物鉴定、层积过程中激素含量的测定、赤霉素处理以及结合室内发芽试验，对种子休眠原因、休眠解除以及人工加速老化过程中SOD、CAT等保护酶活性、MDA含量和种子浸出液电导率的变化进行了研究。主要研究结果如下： 1．北美鹅掌楸种子种皮透水性较好，不是引起种子休眠的原因。 2．外种皮含有抑制物质，不同浓度外种皮浸提液对白菜种子萌发的影响差异不显著，不是引起北美鹅掌楸种子休眠的原因，但对幼苗的高生长和根生长有一定的抑制作用。 3．北美鹅掌楸种子在低温层积过程中，IAA、GA₃含量总体上呈上升趋势；ZR含量的变化出现波动性，且在种子中的含量很小；而ABA含量在层积过程中呈现出明显的下降趋势；IAA／ABA、GA₃／ABA和ZR／ABA的比值在层积过程中表现出上升趋势。 4．北美鹅掌楸种子在裸层积过程中，激素含量变化比较复杂。IAA、GA₃、ZR的含量出现波动性，但IAA／ABA、GA₃／ABA、ZR／ABA的比值呈上升趋势。 5．北美鹅掌楸种子中含有抑制物质ABA，这可能是引起种子休眠的原因，休眠的解除并不仅仅取决于某种激素的含量，而是取决于发芽促进物质与抑制物质的平衡。 6．赤霉素处理能促进北美鹅掌楸种子的萌发，但不能明显地打破种子的休眠。 7．本研究认为，低温沙藏层积处理180d和裸层积处理120d打破北美鹅掌楸种子休眠的效果最好，处理后的发芽率分别为88％和90％。 8．北美鹅掌楸种子老化初期（1～5d）SOD、CAT保护酶活性增加，MDA含量和种子浸出液电导率有所下降；老化后期（5～20d）SOD、CAT保护酶活性迅速下降，MDA含量和种子浸出液电导率上升。研究表明，老化初期北美鹅掌楸种子具有一定的抗老化能力。更多还原

【Abstract】 The dormancy of forest tree seeds is a kind of eco-physiological property formed by plants to adapt the environment so that the species can live from one generation to the next generation and evolve normally. The dormancy is a good characteristic for plants’ existing and developing, but is also inconvenient and difficult for seed germination. Therefore, the study on the property of seed dormancy and the methods of removing seed dormancy is one of the most important tasks in seed-research area.Seed dormancy and the way to overcome it, the water absorption character of seedcoat, the SOD and CAT activities, MDA content of liriodendron tulipifera L. were studied And GA3, IAA, ABA and ZR contents of seeds were measured in 2003 and 2004 at Nanjing Forestry University. The results were shown as follow:1.The seedcoat of liriodendron tulipifera L. has an excellent character of water absorption. So it may be not the main reason of seed dormancy.2.The outer coat of liriodendron tulipifera L. seed contains some germination inhibitors which have no significant effect on seed germination. So it also may not be the main reason of seed dormancy. But the inhibitors have significant effects on seedling height and root growth of Brassica Pekinensis.3.During the process of low temperature stratification, ABA content decline rapidly; GA3 content and IAA content rise; ZR content is just a trace in the seed and has no special changing pattern. IAA/ABA , GA3/ABA and ZR/ABA ratio rise rapidly.4.During the process of naked stratification at low temperature, hormone contents have a complex changing trend, but IAA/ABA, GA3/ABA and ZR/ABA ratio rise rapidly.5.The inhibitor, which is in the seed such as ABA, may be the main substance which causes seed dormancy. Dormancy breaking not only depends on the content of some kinds of hormone but also on the equilibrium of GA3, IAA, ZR and ABA.6.The treatment with GA3 can improve the seed germination, but it can not break seed dormancy completely.7.The 180d low temperature stratification treatment and 120d naked stratification treatment are he best way to break seed dormancy. The germination percentages of Liriodendron tulipifera L. seed with above two kinds of treatments are 88% and 90% respectively.8.SOD and CAT activitives of seed increase while MDA content and Electricalconductivity decrease at the beginning of aging (from 1d to 5d), but vice versa at the late aging period (from 5d to 20d).更多还原