【作者】 于向芝；

【导师】 贺晓；

【作者基本信息】 内蒙古农业大学 ， 野生动植物保护与利用， 2007， 硕士

【摘要】 在内蒙古典型草原地带,选择有代表性的羊草+大针茅群落的放牧退化演替变型—冷蒿+糙隐子草群落实行封育禁牧。并对未禁牧群落(退化群落)、禁牧7年的群落和禁牧20年群落的11种主要植物茎、叶的解剖结构特征及其可塑性进行比较研究,以探讨过度放牧对植物结构的影响。过度放牧后,群落植物整体角质层加厚,叶肉细胞密度增加,有些植物叶片变厚、上表皮细胞变大、最大导管的导管壁厚度增加、维管束密度增加、木质部厚度/韧皮部厚度增加以及植物茎机械组织的细胞壁厚度增加,植物叶、茎表现旱生结构和旱生结构加强的特性。禁牧恢复演替后植物旱化特性减弱,同时,植物输导结构加强,具体体现在植物茎导管口径、导管个数,木质部厚度、维管束宽度在恢复演替过程中均表现升高趋势。小型化植物与正常植物相比,植物的解剖结构没有发生本质性的改变,比较稳定。但植物茎、叶结构具有环境可塑性,冷蒿、糙隐子草叶角质层厚度可塑性较大;羊草生长可塑性较大。更多还原

【Abstract】 Representative communities of Artemisia frigida + Cleistogenes squarrosa which was the succession aberration of Leymus chinensis + Stipa grandis community were fenced in the Inner Mongolia typical steppe in 1983 and 1996 in order to observe the community succession processes.11 predominant plants were collected from unfenced community (degenerated community), community fenced for 7 years and community fenced for 20 years. Plant anatomical structures and Plasticity were compared to reveal the Influence of over grazing to plant structures.It was showed: the cuticle thickness of plant , mesophyll cell density of leaves were lower than those before fencing , for some species, leaf thickness、upper epidermis cells、maximum vessel wall thickness of leafs、vascular bundle density of leaf、xylem thickness/ phloem thickness of leaf and cell wall thinkness of stem mechanical tissues in community fenced for 20 years were smaller than those in degenerated community and in community fenced for 7 years. Xerophytic characters of the leaves and stems weakened in the fenced communities. Simultaneously plant conductive structure strengthened in fenced communities , concrete representations were as follow: vessel caliber、vessel amount、xylem thickness and vascular bundle width of stem became highter than that in degenerated communities.Compared with normal plants , small scaled plants did not have essential changes. Showing their structure were stable .But plant leaf and stem had environmental plasticity to some extant. plasticity of Artemisia frigida and Cleistogenes squarrosa were high; Leymus chinensis showed growth plasticity.更多还原