在干旱、少雨地区成功造林是全世界的难题 ,影响我国植树造林成活率的重要因素之一也是水资源的缺乏。土地的沙漠化带来了生态环境的恶化 ,人民生活的贫困。它已成为各国政府的心腹之患，因此 ,寻求一种雨季吸水、旱季放水的物质为植物生长持续提供水分 ,成为科学家研究的热点 Successful afforestation in arid and dry areas is a worldwide problem. One of the important factors affecting the survival rate of afforestation in China is also the lack of water resources. The desertification of the land has brought about the deterioration of the ecological environment and the poverty of people’s lives. It has become the henchman of governments. Therefore, it is a hot topic for scientists to seek a substance that absorbs water during the rainy season and releases water during the dry season.