贺兰山不同生境旱生灌木的解剖学研究

ANATOMY OF XEROMORPHIC SHRUBS LIVING IN DIFFERENT HABITATS OF HELAN MOUNTAIN

贺兰山荒漠地带三种不同基质生境的２０种旱生灌木的营养器官的比较解剖学研究表明：其共同特点是叶片的表面积／体积的比值小，叶表具厚的角质层、表皮毛，气孔下陷、并具孔下室，叶向中栅栏组织发达；轴器官中木栓层细胞层数多，皮层较厚，机械组织发达，木薄壁组织及髓部细胞的细胞壁术化加厚，根内都具周皮、木质部的导管分子大小不一、频率较高。此外，根、茎、叶中普遍存在粘液细胞和草酸钙结晶，部分植物的根和茎内有异常维管组织。这些结构特征都与早生环境相关，而不同基质生境中生长的植物尚存在一定差异。

Comparative anatomic studies on vegetative organs of twenty species of xeromorphic shrubs living in different habitats in Helan mountain.The main character of leavesare as follows:small ratio of the exteral leaf surface to its volume;leaves are coveredwith thick corticle and trichomes,the sunken stomata and substomatal chamber are obvious;well-developed palisade tissue occur.The pricipal character of axes are as follows:numerous phellem layers and thick cortex occur; mechanical tissue is well developed.The walls of xylem parenchymalous cells and some cells of pith are heavily lignified;the well-develope periderms are formed in all roots of shrubs;vessel elementswith different diameter are present and their frequency of distribution is higher.In addition,mucilage cells and crystalliferous cells commonly exist in the roots,stems andleaves.Anomarous structures are found to form in stems and roots of some plants.These structure are considered to have important physiological significance to adaptationof dry environment.