沙生植物沙鞭叶表皮微形态特征及其生态适应性研究

Micromorphological Characteristics of Leaf Epidermis and Ecological Adaptation of Psammochloa villosa,a Desert Plant from the Inner Mongolian Plateau

利用光镜对沙生植物沙鞭50个代表种群的叶表皮微形态特征进行了观测、统计和分析,总结了代表种群叶表皮结构的异同,系统探讨了叶表皮微形态特征的分类学及生态适应性意义。结果表明,沙鞭叶表皮由长细胞、短细胞、气孔器细胞和刺毛组成,无微毛、大毛和乳突,表现为典型的狐茅型;脉间长细胞形态和壁波曲程度、短细胞形态和分布式样、气孔器体积大小与分布及副卫细胞形状、以及刺毛形态等在种群间具有明显差异,可将其鉴分为两大类。同时,沙鞭种群叶表皮气孔密度随环境干旱程度的增加而增加,第一类气孔密度大、第二类气孔密度小,这种结构有利于减少其体内水分的散失,进而更好地适应干旱环境,是对荒漠环境的一种微观形态解剖特征性适应。

We comprehensively observed and analyzed the micromorphological characteristics of leaf epidermises from 50 representative populations of Psammochloa villosa through the light microscopic.We summarized the similarities and differences of leaf epidermis structures,and then systematically discussed the significance of taxonomy and ecological adaptability about micromorphological characteristics of leaf epidermises.The leaf epidermis was composed of long-cells,short-cells,stomatal cells and prickle-hairs,but they had no micro-hair,macro-hair and papillae,which belongs to the typical festucoid type.The obviously different characters,such as the shape of long-cells and curve extent of cell walls,form and distribution pattern of short-cells,volume and distribution of stomas,shape of subsidiary cells and pattern of prickle hair,existed among populations of P.villosa.They can delimitate P.villosa into two groups.Meanwhile,the stomatal density of leaf epidermises in P.villosa increases with the heavier environmental drought.The stomatal density of group Ⅰ is bigger that of group Ⅱ.This structure is very beneficial for P.villosa to reduce the loss of water,which possibly makes it adapt to arid deserts.Thus,it should be a kind of micromorphologically anatomical adaptation to arid deserts.