《植物生理学报》 2016, 52(2): 225-233

苏铁种子的脱水敏感性及温湿条件对种子后熟的影响

田美华, 赵正武, 唐安军^*

重庆师范大学生命科学学院植物环境适应分子生物学重庆市重点实验室, 重庆401331

通信作者：唐安军；E-mail: an_20070710@163.com

摘　要：

本文分析了贮藏温度和介质水分对苏铁种子后熟的影响及种子的脱水耐性。结果表明, 种子是透水的, 新成熟的苏铁种子的胚很小(3.45 mm), 胚的长度/种子长度之比值(E:S)约是0.089。在适宜的条件下, 胚能继续发育和生长, 其子叶胚在萌发时的临界长度约16.38 mm。由此得知, 苏铁种子是形态休眠的。另外, 苏铁种子对干燥脱水十分敏感, 是顽拗性的, 一旦严重失水就会劣变, 甚至死亡。在冷层积(4°C)时, 75%的介质含水量比50%和25%的介质含水量更有利于胚的后熟。而且, 在室温下, 长时间的干藏和水藏都容易导致种子死亡。所以, 保持湿润是保存苏铁种子的关键。此外, 施用GA₃溶液(500 mg•L^-1)处理可以加速冷层积种子的胚的发育, 缩短解除休眠的时间。

关键词：种子繁殖; 层积; 未成熟胚; 形态休眠; 顽拗性种子; 苏铁

收稿：2015-09-21   修定：2016-01-26

资助：重庆市科委科技项目(cstc2013jcyjA00002)、重庆市教委科技项目(KJ1400504)和重庆师范大学校级科技项目(2011SLX34)。

Desiccation sensitivity and effects of temperature and moisture content of the substrate during storage on after-ripening in seeds of Cycas revoluta

TIAN Mei-Hua, ZHAO Zheng-Wu, TANG An-Jun^*

Chongqing Key Laboratory of Molecular Biology of Plant Environmental Adaptations, College of Life Sciences, Chongqing Normal University, Chongqing 401331, China

Corresponding author: TANG An-Jun; E-mail: an_20070710@163.com

Abstract:

This article fully compared effects of both temperature and moisture content of substrate during storage on the embryo development in seeds of Cycas reveloluta as well as desiccation tolerance. The results showed that the seed with the mesotesta (or sclerotesta) and endotesta was water permeable, and the embryo was highly small and immature (ca. 3.45 mm) with the low ratio of the embryo length to the seed length (E:S), namely, E:S=0.089. The seeds must continue developing and growing to a proper size prior to germination. And the critical length of embryo with cotyledon was near 16.38 mm for germination. Thus, the data confirmed that there existed morphological dormancy in the seeds of C. revoluta. Also, the seeds were sensitive to drying because serious water loss induced sharp decrease in seed vigor, even resulted in total death. So the seeds of this species should be considered recalcitrant. In addition, 75% of the moisture content of the substrate was better than 50% and 25% for embryo after-ripening. Moreover, both long-term dry storage in air and wet storage in water were destructive. Therefore, we thought that keeping seeds moist enough not wet was the key to effectively conserve seeds ex situ. Notably, application of GA₃ solutions (500 mg•L^-1) could accelerate the embryo development of cold stratified seeds.

Key words: regeneration from seed; stratification; immature embryo; morphological dormancy; recalcitrant seeds; Cycas revolute