干热河谷两种植物的旱生结构特征与其分布规律的关系

The Relationship between Xeromorphic Structures and Distributions of 2 Plants in Dry-hot Valley

以干热河谷稀树灌丛植被类型的优势种木棉(高大乔木)和坡柳(灌木)为材料,采取石蜡切片法和光学显微技术,对木棉和坡柳的根、茎、叶解剖结构进行比较,分析这2种干热河谷植物的旱生结构特征。结果表明,木棉和坡柳的根均表现出高度的木质化,其中坡柳根的维管柱直径/根直径和木质部面积/根横切面积分别为85.16%、38.16%,而木棉则为76.51%、20.56%;木棉茎为肉质化茎,坡柳茎则表现出高度木质化;坡柳叶片上、下表皮细胞分别为木棉的2.23倍、1.97倍。在选取的旱生结构的各指标中,除髓面积/茎面积和叶片厚度以外,坡柳的根、茎、叶的其他旱生特征指标均比木棉高,因此坡柳比木棉具有更典型的抗旱结构,分布范围更广。

By comparing the anatomical structures of root, stem and leaves of Bombax ceiba and Dodonaea viscose and by using paraffin method and optical microscope technology, the xeromorphic structures of these 2 dry-hot-valley plants were analyzed in this study. The results showed that these 2 species had highly lignified root, the ratio of vascular cylider diameter to root diameter and xylem area to stem transverse section area of D. viscose were 85. 16%, 38. 16%, those of B. ceiba were 76. 51%, 20. 56%; The stem of B. ceiba showed a high degree of succulence, while D. viscose showed a high degree of lignification; The thickness of upper and down epidermis of D. viscose were 2. 23 times and 1. 97 times of B. ceiba. In terms of xeromorphic indexes, except the ratio of marrow area to stem transverse section area and thickness of leaf, other indexes showed that the drought resistance capabili-ty of D. viscose was higher than B. ceiba. In this sense, D. viscose has typical xeromorphic structure and its distribu-tion areas are larger than that of B. ceiba.