铁路沿线沙区段典型沙生植物植冠种子库的种子脱落特性

通过野外监测和模拟试验的研究方法,研究了铁路沿线沙区段2种典型沙生植物植冠储藏的种子在风吹、滚动、浸水、加热等不同干扰条件下的脱落特性.结果表明：①风吹滚动是促成沙米植冠种子库种子脱落的主要因素之一,通过植株滚动传播种子是以沙米为代表的1年生植物植冠种子库传播种子的主要方式之一;②浸水加热是促成差巴嘎蒿植冠种子库种子脱落的主要因素之一,通过吸湿开裂传播种子是以差巴嘎蒿为代表的多年生植物植冠种子库传播种子的主要方式之一;③沙生植物植冠储藏种子的脱落因所处部位和方向而存在差异,处于植株内层和处于下风向的种子更不易脱落.典型沙生植物植冠种子库通过经历风吹、滚动、浸水、加热等事件脱落种子,并为远距离传播、形成埋藏植冠种子库、分摊萌发风险、扩大种群范围等创造有利条件,独特的繁殖适应对策所反映出的生态功能对铁路沿线沙区段的植被恢复研究具有重要的科学指导意义.

Seed Abscission Characteristics of Canopy-Stored Seeds of Typical Psammophyte Along with Railway Line in Sand Dune Areas

The seed abscission character of canopy-stored seeds of 2 typical psammophytes under different disturbance conditions （blowing,rolling,dunking and heating） were studied by field investigations and simulation experiments in sand dune areas along with the railway line.The results showed that：①For canopy seed bank of annual psammophyte such as Agriophyllum squarrosum,blowing and rolling is one of the main abscission fashions,and plant rolling is one of the main dispersal fashions,②For canopy seed bank of perennial psammophyte such as Artemisia halodendron,dunking and heating is one of the main abscission fashions,and hygrochastic character is one of the main dispersal fashions,③The seed dispersal of canopy seed bank is depended on plant positions and directions,and the seeds are dispersed slower in the inner whorl and at the leeward of the plant.Typical psammophyte disperses seeds by blowing,rolling,dunking and heating,which is good for long distance dispersal,formation of buried-canopy seed bank,reducing germination risk and expanding the scope of the population.The special ecological function of canopy seed bank has some implications in the vegetation restoration along with the railway line of sand dune areas.