| At present, desertification is the most serious realistic problem in arid area.It is also the main environmental problem human being facing. There are lots of problems related to arid land that need to be resolved , however , the most of all are involved in the steady of the eco-environment and oasis. The key pointin building up a steady ecosystem should be based on finding out the relatin-ship between plant and environment. Ascertaining some laws and utilizing those laws are of the most important theoretical and practical significance for the eco-environment recovering and rebuilding in arid area (Peiyou Huang, 1993).Comparing to humid region, the bio-diversity of arid area has been strongly restrained for the lack of water. But there still are some kinds of native xeroph-ytia which have distributed naturally during the long term process of adapta-tion and evolution in arid region . Needless to say , it is the most key step to promote the vegetation restoration in desertification area by ascertaining the controlling factor of the natural distribution and observing the adaptation law of the plant living in arid area . Many researches show, the environmental adaptable process of the xerophytecan be divided into two different stages. In the first stage, seeds sprout and fini-sh the adaptation xerophytic process ; in the second stage,xerophyte grows in arid condition by using natural water. Weather or not the vegetation restorationand rebuilt can be achieved will largely depend on weather or not sprout can build up the mechanism to resist dry stress.This point of view has been pro-ved by plants living on the natural water .Usually the xerophyte has particular ability to endure drought for long term. But it also need enough water in the pro-cess of seed sprouting and sprout growing;this is even necessary in the earliest stage of its life, when sprout faces the quickly upcoming hot summer. The sho-rtage of water is a severe challenge to the life of sprout. The fact that the xerop-hyte grows naturally in desert presents that the sprout of xerophyte has special adaptive ability to endure the first draught season in its life . It is the most essential factor for the sprout of the xerophyte going through the first hot summer to build up the xeromorphic structure and physiological function .From this point, this study frees from the traditional limit which focuseson adult plant only, putting the stress on studying the dynamic adaptive change of the structure and function of the sprout. The ways of study are followed: insp-ecting and observing their living condition on the open fields ;cultivating sp-rout, examining physiological and biochemical changes in plants; paraffin sec-tioning .The study results show: due to the species diversity, though the sproutsof xerophyte have several strategies to adapt to environmental drought in the long term evolution process,they have obtained same adapting mechanism to the short of water.There are many adaptive changes in the two research subjects (Artemisia.songarica Schrenk.and Seriphidium.santolinum(Schrenk)Polijak.) in morphology and anatomy ,such as with the increase of the daily age, the root-shoots ratio increased ; the root became stronger; the ratio of leaf volume and leaf area increased ; the volume of epidermic cell decreased;the cut-icle and phellem layer on the surface of root thickened . Stoma caved in leaf;epidermal hair of leaf and stem well-developed, palisde tissue developed well , the cell gap decreased;the spongy tissue disappeared;leaf is kinds of isolateralthat is the typical xeromorphic structure; crystal cell and fibric cell increased ; conducting tissue and mechanical tissue developed well; bundle sheath appeared. The adaptive changes in physiological function are followed: with the increase of the daily age, water potential and total water content decreased gradually; the content of Pro increased gradually; the bound water and the ratio of bound water and free water increased gradually ;...
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