Morphological And Structural Features Of Six Typical Alpine Cushion Plants’ Leaves Adapt To The Alpine Environment

The Alpine cushion plants which growing in the extremely arid soil with the harsh weather environment is very sensitive to the variation of global climate, and it plays an important role in forming the species diversity of alpine ecosystems, and maintainning the ecosystem function stability and other aspects, Therefor explaining how alpine cushion plants adapts to the cold environment have great scientific value. By studying the morphological characteristics of alpine cushion plants which adapted to the extreme environments in different climatic zones, we can reveal,as constructive species,how does cushion plants growth and development. Previous studies have shown that leaf morphology of many plants will be changed along altitude. But it is still unknown whether cushion plants which growing under extreme conditions will show the same variation.In this article, the scanning electron microscope and transmission electron microscope were used to analyze Rhodiola fastigiata、Thylacospermum caespitosum、Arenaria kansuensis Maxim、Arenaria densissima 、 Potentilla microphylla and Leontopodium nanum which growing at different altitudes from five west provinces in China.The purpose of the research is elucidating the adaptative mechanism of acrophytia to the psychro-environment both from the external form and cell ultrastructure of lamina.The main conclusions are as follows:1) The blade surface morphology, including stomatal density, stomatal opening axial ratio, pore size, pore size of the opening, pores aspect ratio, and cuticle width, changes differently along altitude in different species, but showing the opposite trend in general;2) Leaf characters of different parts there are significant differences;3) Along with altitude increasing, the number and the size of chloroplasts increases, the shape of chloroplasts shift gradually from the spindle gradually to oval, and the number of layers of sheet becomes less, Cell wall thickness increases.4) The mitochondrial shape changes significantly as altitude increasing, and shift gradually from oval to an irregular shape; the size becomes smaller while the number increases;5) big central cell vacuoles appears in the center of the cell, thylakoid gradually irregular arrangement, part of the region distortion, deformation, expansion.The results indicate that cushion plants adaptive to high altitude environment mainly through the change of both external morphology and cell ultrastructure features. Research on the adaptability of alpine cushion plants to its growing environment, providing a theoretical basis to elucidate the formation mechanism and function of the alpine ecosystems, and a scientific guidance for the biodiversity conservation, ecological environment construction and cushion plants’ artificial rearing.