濒危植物鄂尔多斯半日花种皮结构的研究

Study on the Structure of Seed Coat of Endangered Plant Helianthemum ordosicum

借助双目解剖镜、普通光学显微镜及扫描电子显微镜对鄂尔多斯半日花(Helianthemumordosicum)种子的形态结构及种皮的结构进行了细致观察.种皮表面覆盖一层白色粘液物质,遇水后迅速膨胀,可将种子粘附于沙子或砾石上,这可能有利于种子的吸水与萌发.成熟种子的种皮结构可明显区分为表皮层和表皮下层两部分.种皮的内、外表面均密布孔、缝,是水分和空气进出的通道.种脐周围种皮内陷折转,纵切面观似"ω"字形,种脐小孔正下方的数层紧密排列的短柱状细胞,可能有控制水分从种脐小孔进出的功能.

The seed morphology structure and structure of seed coat of Helianthemum ordosicum were carefully obsevered with light microscope,olympus microscope and SEM. The results showed that the outmost layers of the seed coat were covered by a layer of white mucilage which expanded quickly with absorbing water and could hold sand particles and gravel on the seed.This facilitate the seed germinating and absorbing water. The seed coat structures of the fullgrown seeds could be clearly separated epidermis and epidermal underlayer. The inner and outer surfaces of the seed coat were densely covered with foramens and finestras which could permit water and air entering and going out. The seed coat around hilum curved inwards and turned over, and the vertical section of the hilum cooked like 'ω' from. Several layers of short colum cells compactly arranged under the hilum foramens could controlled water entering and going out.