干旱区生态环境知识资源中心

Leymus racemosus, the mammoth wild rye, is a rhizomatous perennial grass, mainly distributed in the moving or semi-stabilized sand dunes in deserts of the Junggar Basin in Xinjiang, China. The revival ability of the young seedling after periods of desiccation can be influenced by several factors: (1) the stage of seedling development - the later the stage at dehydration, the longer the root length and the lower is the percentage of seedlings that survive; (2) the length of the period of desiccation - the longer the period that the seedlings are under desiccation, the lower is the percentage of seedlings that survive; (3) endosperm size - the smaller the proportion of endosperm that remains in the caryopses, the lower is the percentage of seedlings that revive, determined by (a) the stage of seedling development, and (b) the proportion of the endosperm that is removed by cutting; and (4) caryopsis size - the larger the polymorphic caryopses, the higher is the percentage of young seedlings that revive from periods of desiccation. The physiological and ecological implications of L. racemosus seedling desiccation tolerance are that under extreme desert and unpredictable environmental conditions, the chances of seedling establishment are increased.