摘 要

白玉兰（Magnolia denudata Desr.），木兰科木兰属落叶乔木，是名贵的园林花木 之一。本文以白玉兰种子为主要研究对象，对其休眠特性进行了研究，通过测定白玉兰 种子在层积过程中相关指标的变化，初步了解了其胚休眠的类型，并探究了休眠的解除 方法，主要结果如下：

1、白玉兰种子的离体胚无法萌发，进一步研究表明白玉兰种胚具有形态生理休眠， 是造成其采收后无法立即萌发的主要原因。

2、推迟白玉兰种子的采收时间，有利于胚的形态发育，但无法解除胚的生理休眠。

3、一定的高温有利于白玉兰种胚的形态发育（25±5℃），但种胚生理休眠的释放需 要一段时间的低温处理(4℃)，赤霉素（GA3）处理可以代替这一低温过程。

4、低温层积（4℃）40 d 和变温层积（15℃-4℃）50 d，都能有效解除白玉兰种胚的 形态生理休眠。低温层积结合不同浓度 GA3 处理，在层积前 30d 时，种子发芽率与对照 有显著差异，且 GA3 浓度越高，效果越好。

5、白玉兰种胚休眠解除的过程中，需要积极动员内部的贮藏物质，可溶性糖在代谢 过程中不断被消耗，呈现不断下降的趋势。蛋白质含量的上升，说明种子内代谢旺盛， 各类酶活性增强。

关键词：白玉兰种子；胚休眠；物质代谢

Studies on the Embryo Dormancy Characteristics of

Magnolia denudata Seeds

ABSTRACT

Magnolia denudata Desr. is one of the most valuable ornamental trees in China, which belongs to Magnolia genus under Magnoliaceae family. This paper mainly studied on the embryo dormancy characteristics of Magnolia denudata seeds, which were measured by dynamic changes of related physiological and biochemical indicators during stratification. Preliminary explorations of their embryo dormancy type and dormancy release methods were made. The main results are as follows:

1. The vitro embryos of Magnolia denudata seeds cannot germinate. Further studies have shown that Magnolia denudata seeds have morphophysiological dormancy, which is the main reason of that the seeds cannot germinate immediately after harvest.

2. Postponing the harvest time of Magnolia denudata seeds help complete the morphological development of the embryos, but could not break the physiological dormancy.

3. High temperature is conducive to the morphological development of Magnolia denudata embryos (25±5 ℃), but the release of physiological dormancy required a period of cold treatment (4 ℃), and gibberellic acid (GA3) treatment can replace the low temperature

process.

4. Cold stratification (4 ℃) for 40 days and variable temperature stratification

(15 ℃-4 ℃) for 50 days both can effectively relieve the morphological and physiological dormancy of Magnolia denudata seeds. Combined with various concentrations of GA3

treatment and cold stratification, the germination rates were significantly different with the control during the first 30 days, and the higher the concentration of GA3, the better.

5. The embryo dormancy of Magnolia denudata seeds release process need to actively mobilize internal storage substances. Soluble sugars were constantly being consumed in the metabolic process, showing a declining trend. Protein content increased, indicating that the seeds inside metabolism and the activities of enzymes increased.

Keywords: Magnolia denudata seeds; Embryo dormancy; Metabolism

目 录

1 文献综述.........................................................................................................................................................1

1.1 种子休眠的研究概况......................................................................................................................... 1

1.1.1 种子休眠的概念...................................................................................................................... 1

1.1.2 种子休眠原因及分类的研究.................................................................................................. 1

1.1.3 解除种子休眠方法的研究...................................................................................................... 2

1.2 木兰属植物的研究进展..................................................................................................................... 4

1.2.1 木兰属植物资源的研究.......................................................................................................... 4

1.2.2 白玉兰种子休眠特性的研究.................................................................................................. 4

2 材料与方法.....................................................................................................................................................5

2.1 白玉兰种子形态特性的研究............................................................................................................. 5

2.1.1 试验材料.................................................................................................................................. 5

2.1.2 种子生活力测定...................................................................................................................... 5

2.2 白玉兰种子胚休眠特性的研究......................................................................................................... 5