摘 要

为了探明珙桐种子发芽抑制物的存在部位及其在层积过程中抑制活性的变化情况，测定了低温层积12个月与16个月珙桐种子其种仁和种壳中内源抑制物的生理活性。实验中分别以甲醇、丙酮、蒸馏水为浸提剂，制备了珙桐种仁、种壳浸提液，并研究各浸提液对白菜种子发芽的影响，并分析层积过程中珙桐种子内含抑制物的生理活性变化情况。结果表明：珙桐种子种仁与种壳内均含有发芽抑制物；随着浸提液浓度的升高，对白菜籽发芽的抑制效果也逐渐增强；相同浓度种仁浸提液的抑制效果比种壳的强；采用各提取剂提取的抑制物生理活性为：甲醇＞丙酮＞水。层积16个月后，抑制物生理活性降低，但种子经变温层积12个月后，以0.06 g·mL^-1的种仁甲醇浸提液处理的白菜籽其发芽率仅为45.00%、发芽指数为8.25，这表明珙桐种子经12个月的变温层积处理其抑制物的生理活性仍较强，说明该种子具有深度休眠的特性。

关键词：珙桐；抑制物；变温层积

The influence of inhibitor in Davidia involucrata seeds on cabbage

ABSTRACT

Physiologically activities of inhibitor in Davidia involucrata seeds’ kernel and shell were determined at various stages of variable temperature stratification during 12 months and, respectively, 16 months: Leaching solutions of kernel and shell in E.konishii were prepared by using methanol, acetone, distilled water respectively as extraction solvents. Respectively, as extraction agent, and researching the effect of various extraction solvents on seed germination of cabbage. Effects of different leaching solution on seed germination and seedling growth in Brassica campestris and changes of physiological activity of inhibitor in D. involucrata seed were researched during variable temperature stratification. The results indicate that germination inhibitors and growth inhibitors exist in both kernel and shell of D. involucrata. With increasing mass concentration of leaching solution, physiological activity of inhibitor is increased gradually. Physiologically activity of inhibitor in kernel leaching solution is significantly higher than that in shell leaching solution. Physiologically activity of inhibitor in various material: methanol＞propanol＞drilled water. Physiologically activity of inhibitor got lower at various stages of variable temperature stratification after 16 months. However, taking seeds stored through variable temperature stratification for 12 months as materials, relative germination rate of Brassica campestris seeds is barely 45.0%, which is treated by methanol leaching solution of kernel, and its germinating index is barely 8.25.It indicates that inhibitor in Davidia involucrata seed remains strong physiological activity after variable temperature stratification for 12 months. So D. involucrata seed has the characteristic of deep dormancy.

Key words: Davidia involucrata seeds; inhibitor; variable temperature stratification

目 录

1 文献综述 1

1.1 选题依据 1

1.2 国内外研究进展 2

1.2.1 种子萌发抑制物研究 2

1.2.2 珙桐休眠的研究 7

1.3 方案拟定 9

1.4 展望 9

2 材料和方法 10

2.1 实验材料 10

2.2 实验方法 10

2.2.1 提取剂对白菜籽发芽的影响 10

2.2.2 分离种皮与种仁 10

2.2.3 浸提液的制备 10

2.2.4 抑制物的提取 11

2.2.5 培养液的制备 11

2.2.6 内源抑制物对白菜籽发芽的影响 11

2.3 数据分析 11

3 结果与分析 12

3.1 提取剂对白菜籽发芽的影响 12

3.2 层积12个月后种仁不同浓度浸提液对白菜籽发芽的影响 12

3.3 层积一年后种壳不同浓度浸提液对白菜籽发芽的影响 13

3.4 层积一年后不同部位甲醇浸提液对白菜籽发芽的影响 14

3.5 不同层积时间种子甲醇浸提液对白菜籽发芽的影响 15

3.6 不同提取剂提取液对白菜种子发芽的影响 16

4 讨论 18

4.1 种子内源抑制物与种子休眠的关系 18

4.2 种壳和种仁中抑制物对白菜籽发芽影响的差异 18

4.3 层积处理对种子内源抑制物含量变化的影响 19

结 论 20

致 谢 21

参考文献 22

1 文献综述

珙桐(Davidia involucrata Baill.)属珙桐科(Davidiaceae)，是第三纪热带植物区系孑遗植物，为我国特有的珍稀濒危植物，被列为国家一级保护植物。100万年前，珙桐广泛分布于世界许多地方，但是经过第四纪冰川的灾变，它在全球大多地方都已消失，仅仅在中国云南、贵州、四川、陕西、湖南、湖北等少数几个省的局部地区得以幸存，被称为活化石。珙桐树形优美、花姿奇特，花形酷似展翅飞翔的白鸽而被西方的植物学家称为“中国鸽子树”，是世界著名的园林绿化树种，有很高的观赏价值。珙桐常植于池畔、溪旁及疗养所、宾馆、展览馆附近，并有和平的象征意义。用时它材质沉重，是建筑的上等用材，可制作家具和作雕刻材料。

珙桐种子休眠期长，萌芽率低，繁殖非常困难,在林中自然掉落的果实自行萌发的极少。因此展开珙桐休眠机理的研究，寻找抑制种子萌发的物质，提高其发芽率和整齐度是关系到珙桐保护和开发利用的关键因素。