Abstract:

Polar vascular plants have attracted attentions due to the special environment where they grow. Here we review the progress on structure,physiology,genetics and origin of polar vascular plants in recent years. These researches gave the knowledge of polar vascular plants including the adaptation mechanism,the feature of genetic diversity,and the patterns of colonization and origin. The ultrastructural features of leaves such as the protrusion of chloroplast and the close special contact of chloroplast and mitochondria were considered in relation to the adaptations of the plants to the conditions in the polar region. The accumulations of carbohydrate,proteins,the regulation of enzymes,and the express of genes stimulated by stress under low temperature and long day permitted the plants to survive in the harsh polar condition. The secondary metabolites contents changed with the intensity of ultraviolet radiation and light,which protected the plants from strong radiation. The genetic diversity and colonization patterns of vascular plants were affected by the geographical and climatic environment of the polar. The populations of Deschampsia antarctica showed low genetic diversity,and low level of gene flow occurred between neighboring populations. The colonization pattern of D. antarctica accorded with stepping-stone model,while the arctic plants had the long-distance colonization. The viewpoints from several fields of science indicated that the vascular plants were most probably migrated to Antarctica through bird aid.