贺兰山10种不同植物的旱生结构研究

对贺兰山10种不同生活型植物的形态解剖研究表明，长期生长在干旱贫瘠环境中植物，均形成适应生境的一些特殊形态结构．叶器官主要表现在：（1）叶表面积与体积之比缩小，表面覆有厚的角质膜，并被有表皮毛，气孔下陷，具孔下室；（2）栅栏薄壁组织细胞明显增多，海绵薄壁组织细胞减少．有叶肉不分化叶、等而叶和异而叶3种结构形式；（3）叶内贮水组织和机械组织增强。轴器官主要表现在：（1）根普遍形成周皮，且木栓层细胞层数增多；（2）机械组织非常发达，在周皮、皮层和韧皮部中有许多厚壁细胞分布。维管组织中的木薄壁细胞的细胞壁也明显木质化加厚；（3）有些植物的根具有异常维管组织。另外，这些植物根、茎、叶中均有粘液细胞和含晶细胞分布。这些结构具有重要的适应干旱生境的意义。

AN ANATOMICAL STUDY ON XEROMORPHIC STRUCTURE OF THEDIFFERENT LIFE FORM PLANTS IN HELAN MOUNTAIN

The morphological and anatomical studies on ten species of different life form plantsin Helan Mountain was observed. In order to adapt dry and barren habitats,these plantsformed some special types of structures. The main characters of leaves are as follows:small ratio of the external leaf surface to its volume;epidermis with thick corticle,trichomes, sunken stomata and substomatal chamber; well--developed palisade tissue andundeveloped spongy tissue. The leaves have three types of mesophylls:undifferentiatedmesophyll,isobilateral mesophyll and bifacial mesophyll. Water storage tissue andmechanical tissue are well developed. The principal characters of axes are as follows: rootsof all plants form well--developed periderms and numerous layers of phellem. Machallicaltissue is well--developed,there are many sclerenchyma cells exist in the periderms,cortexand phloem,the cell walls of wood parenchyma are heavily lignified. Some of the roots ofthe plants have abnormal vascular tissue. Otherwise, mucilage cells and crystalliferouscells commonly exist in the roots, stems and leaves. These structures are considered tohave important physiological significance to adaptation of arid habitats.