乌鲁木齐河源区不同海拔的火绒草叶片结构特征的比较研究

Comparative Study of the Characteristics of Leaf Morphological Structure of %Leontopodium leontopodiodes (Compositae)for Three Elevations at the Source Area of the rümqi River

采用PEG和Epon 812二次包埋方法,利用光学显微镜和扫描电子显微镜对乌鲁木齐河源区海拔4000m、3400m、2500m三种不同高度的火绒草(Leontopodiumleontopodiodes(Willd.)Beauv.)叶片剖面及表面结构进行了观察.结果表明:火绒草叶片既具有中生植物又兼有旱生和湿生植物的部分结构特征;其叶片厚度、表皮细胞外壁角质层表面、外角质层蜡质分泌物的有无、表皮细胞形状、气孔器分布特征、保卫细胞极区"T"型角质加厚程度、气孔开口(长/宽)、气孔密度、维管束形态、CTR值、叶肉细胞叶绿体含量等性状特征,在不同海拔的火绒草间呈现出明显差异;而表皮的气孔水平位置类型、毛状附属器等性状则差异较小.数值分析火绒草叶结构各类性状以及不同性状状态的组合,显示出个体形态的多样性及其对高山环境和海拔高度的适宜性特征.

The main anatomical and surface characteristics of leaves of %Leontopodium leontopodiodes% (Willd.) Beauv. from three habitats of 4 000 m, 3 400 m and 2 500 m a. s. l. in the source area of the rümqi River were analyzed and compared by means of light and scanning electron microscope using a new embedding method with PEG and Epon-812. The results indicated that %Leontopodium leontopodiodes% at the source area of the Urumqi River is the mesophytes with part leaf structural characteristics of xerophytes and hydrophytes. Above the habitat of 4 000 m a. s. l., the surface of cuticle of the leaf epidermis wall of %Leontopodium leontopodiodes% agrees with granular wax. The other two habitats not agree with granular wax. Many characteristics are distinctly different for different habitats, such as the thickness of leaf, epidermis shape and the pattern of anticlinal wall, and the distribution characteristics of stomatal apparatus, stomatal size, stomatal density, formation of vascular bundle, %CTR%, chloroplast content of mesophyll tissue and the cuticilar thickness degree of polar !T' shape of guard cells. However, fewer characteristics of the hair-shaped appendant organ and the plane station type of stomata change on the epidermis. It is revealed that the diversity of individual morphology and the combination of characteristics of the leaf morphological structure are correlated with habitats.