Abstract: The amount of aoiuble sugar and polysaccharid contents and their daily changes and the amount of pleysccbairde whewn water less is 50% of the total in several psmmophyte leaves were measored with chonatography and the cholorimetry.The result have shoen that the maxinum contents of the soluble sugar in day time in Ammopiptanthus mongolica(Maxim)cheng f.Nitraria tangucorum,Zygophyllum xanthoxylon,Artemsia sphaerocephala and oxytropis aciphylla are respectively 16%,8%,14%,11% and 5%.In the first three Plant the maximum contents are 5.6%,7.6%,and 7.5%.Therefore,there is a mutualty conplenetary relation between daily process and soluble sugar.When water loss is 50% of the total,polysaccaride in Nitratia tangurorum increase by 1.31times,and in Zygophyllum xanthoxylon increase by 1.2 times.Ammopiptanthus mongolica(Maxim)cheng f.only increase by 0.44 times.The results indicate that some psammophytes rely on meressing soluble sugar to increase osmotic adjustment tm to endure drought conditions,while others rely on increasing polysaecharide to strengthen colloid formarion to store more water to adapt dry conditions,and some other kinds of psammophy tolerate dry conditions in both ways.

Key words: Psammophyte, Sugar contents, Drought resistance