新疆短命植物抱茎独行菜种子粘液质特性的研究

以新疆荒漠植物抱茎独行菜为材料,运用光镜与扫描电镜观察以及紫外吸收光谱法、化学反应及种子萌发实验等方法,对粘液质的形态和结构,物理化学特性,粘液质对种子萌发及萌发后的影响进行了研究.结果显示:(1)完整干种子表面覆盖着一层膜状物质(完全脱水的粘液质),并呈同一走向的山脊状突出的网状结构,遇水后粘液物质呈射线状向外发射出来,化学反应实验结果表明,粘液质的组成可能是某种多糖,如β-葡聚糖.(2)粘液质约占干种子重量的1/4,有很强的吸水能力,完全浸润10 min后,种子重量增加约30~40倍,种子长度、宽度、厚度的增加分别多于1倍、2倍、4倍;完全润湿的种子能够粘附相当于其干种子重量68倍的沙粒.(3)种皮粘液质对于不同土壤基质中的种子萌发有重要作用,但是对萌发后幼苗的生长没有作用.

Characterization of the Seed Coat Mucilage Properties of Ephemeral Plant Lepidium perfoliatum L.in Xinjiang

In present study,an ephemeral plant species which distributes in Xinjiang desert Lepidium perfoliatum L.was studied on the seed coat mucilage as follows:morphology and structure,chemical and physical properties,effect of the mucilage on seed germination and post-germination by methods of light microscope and scanning electron microscopy observation,UV absorption spectrum,chemical reaction,and seed germination.The result revealed:(1)the surface of intact dry seeds covered pellicle (dehydrated mucilage) layer and displayed structure of network which was ridge-like protuberance along the same direction;when contact with water,the hydrated seed emitted mucilaginous substance as many radial cords.Results of various chemical reactions of mucilage suggested that the component might be some polysaccharide as β-glucan.(2)The physical properties revealed that mucilage accounted for approximately 1/4 of dry seed weight,it had high capacity in water catchment,after fully wetting within 10 min,seed weight increased for about 30~40 times;the seed size increased more than one time in length,two times in width and four times in thickness.In addition,the fully-wetted seeds were able to adhere sand particle to 68 times of the dry seed weight.(3)Seed mucilage was important for seed germination in different soils,but it did not contribute to the post-germination growth.