《植物生理学报》 2016, 52(8): 1231-1242

河岸带植物中华蚊母树种子休眠机制及生态适应性

李晓玲^1,2,*, 程岁寒^1,2, 栾春艳^1,2, 杨进^1,2, 温浩然^1,2, 黄应平^1,2, 黄成名³

¹三峡大学生物与制药学院, 湖北宜昌443002; ²三峡库区生态环境教育部工程研究中心(三峡大学), 湖北宜昌443002; ³三峡植物园, 湖北宜昌443111

通信作者：李晓玲；E-mail: lixiaolinggz@126.com

摘　要：

为探索中华蚊母树种子的休眠特性、破除休眠方法及其生态适应性, 对中华蚊母树新鲜种子的生活力、休眠率、萌发率、离体胚培养、种皮障碍、种皮萌发抑制物及破眠方法进行了研究。结果表明, 中华蚊母树新鲜种子的萌发率和生活力分别为24.99%~43.16%和71.10%~78.67%, 休眠率则为37.01%~53.67%, 表明中华蚊母树种子具有部分休眠特性且休眠具有可塑性。种胚休眠测定结果显示, 中华蚊母树种胚在形态上是发育完全的, 外源GA₃可有效提高种子的萌发率。中华蚊母树种子硬实, 种子含水量为10.31%, 吸水率为20.94%, 坚硬种皮对吸水有一定的阻碍作用。H₂O₂处理种子, 可轻度腐蚀种皮, 增强种皮的透气性。种皮内源抑制物生物学测定显示中华蚊母树种子种皮不存在内源抑制物。周期性光照结合20°C/15°C变温条件和300 mg•mL^-1的GA₃溶液浸泡可提高种子萌发率, 分别为43.33%和53.34%。本研究首次阐明了中华蚊母树种子休眠的主要原因为种皮存在一定的机械障碍、种皮对种胚的机械束缚作用和种皮部分透水、透气性障碍以及一定的内源激素的缺乏引起, 属于综合浅休眠类型。

关键词：中华蚊母树; 休眠机理; 种子萌发; 内源抑制物; 生态适应性

收稿：2016-04-14   修定：2016-07-09

资助：国家自然科学基金(51209122)和三峡大学研究生科研创新基金(2015CX154)。

Seed dormancy mechanism and ecological adaptability of riparian plant Distylium chinense

LI Xiao-Ling^1,2,*, CHENG Sui-Han^1,2, LUAN Chun-Yan^1,2, YANG Jin^1,2, WENG Hao-Ran^1,2, HUANG Ying-Ping^1,2, HUANG Cheng-Ming³

¹College of Biological and Pharmaceutical Sciences, Three Gorges University, Yichang, Hubei 443002, China; ²Engineering Research Center of Eco-Environment in Three Gorges Reservoir Region, Ministry of Education (Three Gorges University), Yichang, Hubei 443002, China; ³Three Gorges Botanical Garden, Yichang, Hubei 443111, China

Corresponding author: LI Xiao-Ling; E-mail: lixiaolinggz@126.com

Abstract:

The seed viability, dormancy and germination percentages, the culturing of embryos, the obstacles of seed testa, the inhibitor of seed germination, and breaking dormancy experiments were conducted to explore the dormancy mechanism of Distylium chinense seeds, techniques for breaking the seed dormancy and its ecological adaptation. The study shows that the viability, germination, and dormancy percentages of D. Chinense fresh seeds are 71.10%–78.67%, 24.99%–43.16% and 37.01%–53.67%, which indicates that the D. Chinense seeds have partial dormancy characteristics with dormancy plasticity. The germination of embryos showed that the embryo structure was fully developed and GA₃ can improve the germination of seed. D. Chinense seed is hardseed. The moisture content was only 10.31%, and the water absorption percentage was 20.94%; the seed water absorption was impeded by seed testa. Seeds soaking in corrosive H₂O₂ enhanced permeability of seed. Biological test to intrinsic inhibitor displays endogenous inhibitor did not exist in seed testa. The cyclical light combined with variable temperature 20°C/15°C and 300 mg•mL^-1 GA₃ solution can effectively break the dormancy and germination percentage were 43.33% and 53.34%, respectively. This study firstly systematically illustrates the reason of D. chinense seed dormancy is due to the mechanical obstacles of shell, the mechanical restraint effect of hard testa on embryo, the gas and water permeability barrier and the lack of endogenous hormones. The results show that the seed dormancy belonged to non-deep combined dormancy.

Key words: Distylium chinense; seed dormancy mechanism; seed germination; endogenous inhibitor; ecological adaptability