风毛菊属3种植物叶的解剖结构比较

Comparative Studies on the Anatomical Structures of Leave of 3 Species in Saussurea

采用石蜡切片法对分布于祁连山海拔5 000 m左右流石滩上菊科风毛菊属水母雪兔子(Saussurea medusaMaxim)、鼠曲雪兔子(Saussurea gnaphalodes(Royle)Sch.)、红叶雪兔子(Saus-surea paxianaDiels.)3种植物叶片的解剖结构进行了比较研究,结果表明:叶片表皮细胞均为单层,上下表皮都有气孔分布,气孔不下陷;角质层较厚,叶表面均被单列细胞的表皮毛。3种植物均为异面叶;叶肉栅栏组织较发达,通常由2-3层细胞组成,但栅栏组织细胞排列较疏松;海绵组织存在大量的细胞间隙;叶肉中通气组织发达,且均有不规则裂生性气腔。叶脉维管束中韧皮部都具有异细胞存在。这些共同特征是3种植物对高山地区缺氧、低温、强辐射等自然条件长期适应的结果。但是,3种植物在叶片的外部形态特征、叶肉栅栏组织细胞的特点、维管束发育程度、内分泌结构、不规则裂生气腔等方面又存在明显的不同,表现出3种植物对环境的适应也是存在差异的。

The anatomical structures of leaves of 3 species i.e. Saussurea medusa Maxim, Saussurea gnaphalodes （Royle） Sch, Saussurea paxiana Diels. in Saussurea grown in Qilianshan （ halt ≈ 5 000 m） were comparatively studied with the method of paraffin section. The obvious features of 3 plant species are as follows ： the cell of upper epidermis in lamna is in one layer and cuticle is thick. The leaves have their stoma in both leaf surfaces and stomata that are not sunken. Epidermal hairs are 1 cell wide. The three plant species are all bifacial leaf. Palisade mesophyll which is made up by 2 -3 layers is well developed, but there is quitle large intercellular spaces among palisade mesophyll and among spongy mesophyll. Aerenchyma is well developed in mesophyll. The three plant species all have anomaly schizogenous intercellular cavity. There is a little idioblasts in the phloem. All these contribut to the results of long-term effects of harsh environment on Qilianshan. There are obvious differences among them such as the color of leaves, the cell characteristic of palisade mesophyll, the development of vascular bundle, the structure of secretory canal, schizogenous irregular cavity, etc.