国产秋海棠属植物种子生物学研究

Begonia species have great ornamental values. Many Chinese Begonia species are endangered and are in dire need of protection. Ex-situ living plant conservation has been a very popular strategy of conservation of Begonia species, but with limitations and are problematic with some species. Seed bank is an efficient and effective way for ex-situ germplasm conservation and can serve as a supplyment with other conservation strategies. So far as we acknowledge, however, investigations of seed storage and seed biology of Begonia species have been very rare in China. The proposed project aims to study seed biology of eight representive Begonia species from China. We will focus on seed dormancy, optimal seed germination conditions, storage behavior, storage longevity, and seed vitality determination of these selected species. Obtained knowledge will help us better understand seed biology of Begonia specis and hence facilitate germplasm conservation and utilization of Begonia species.

秋海棠属植物具有很高的观赏价值。国产秋海棠属中存在为数众多的濒危种类,亟需保护。以往对其保护主要局限于活体植株的迁地保育，存在诸多问题。以种子为材料保存濒危植物具有许多不可替代的优点，并与其他保存方法相互补充。但目前国内尚未开展针对秋海棠属植物种子的保存工作及与之相关的种子生物学研究。本研究拟通过对该属中8种具有代表性的秋海棠种子开展包括休眠状况、萌发条件、储存习性、储存寿命及活力检测方法在内的种子生物学研究，为保存利用秋海棠属植物种子提供理论依据及技术支持。

通过对圭山秋海棠（Begonia guishanensis S.H. Huang et Y. M. Shui）、心叶秋海棠（Begonia labordei H. leveille）、石生秋海棠（Begonia lithophila C. Y. Wu）及独牛秋海棠（Begonia henryi Hemsley）四种秋海棠开展种子生物学研究，首次报道了秋海棠属植物种子中存在的浅生理休眠现象，并首次发现秋海棠属植物的种子萌发对硝酸盐有较强的依赖性，不同打破休眠的方法对这几种秋海棠属植物的种子休眠打破的效果不同，不同种类的种子萌发的最适温度也不相同，石生秋海棠、圭山秋海棠及心叶秋海棠的种子具有浅的生理休眠。进一步的吸水干燥循环处理实验表明较高温度（18/25 ℃）下的吸水/干燥循环显著抑制了四种秋海棠种子在某些温度条件下的萌发；而较低温度（5/12 ℃）下的吸水/干燥循环则显著促进了石生秋海棠、心叶秋海棠及圭山秋海棠的种子在某些温度下的萌发。较高温度（18/25 ℃）下的吸水/干燥循环可能通过诱导出种子的二次休眠而显著抑制了种子在一些温度下的萌发率，而较低温度下（5/12 ℃）的吸水/干燥处理能够打破这种生理休眠。推测旱季早期较低温度下的间断降水有助于打破石生秋海棠、圭山秋海棠及心叶秋海棠的生理休眠；而旱季末期较高温度下的间断降水则有可能会诱导出四种秋海棠种子的生理休眠，独牛秋海棠的种子很可能具有浅生理休眠。