Abstract: Ephemeral plant (Ephemerals) is generic terms a kind of plant group with very short life cycle or growth cycle and the growth cycle is 2 months or so commonly,then part or the whole plant dry dead on the ground and have a bad season in the form of components in below ground organs of dormant seeds. Ephemerals,including annual ephemerals and ephemeroids,are characterized by short-term growth rhythms and specific biological traits adapted to deserts or temperate broad-leaved deciduous forests. Few studies have been carried out on ephemeral community composition and their relationships with temperature and precipitation regimes in the desert. In 2008,we monitored the early-spring ephemeral community change in the Mosuowan area of the Junggar Desert,northern Xinjiang. We also collected temperature and precipitation data to analyze the effects of these factors on ephemeral adaptation. It turned out that the time and amount of the first rainfall were the important factors to determine the time of the germinating,and the precipitation status after seedling had significant effect on the community physiognomy in the current year,while the emergence time of hot-dry season determined the life cycle of the ephemerals. Additionally,Ephemeral plant has a special growth phenomenon with vegetative growth and reproductive growth over the same period,the growth and development of ephemerals showed a very high sensitivity and adaptability to the variations of hydrothermal conditions,especially to the precipitation that appears occasionally. Ephemeral plant “a race against time” growth has high consistency with the water hot configuration.

Key words: ephemeral plants, plant community, species diversity, hydrothermal conditions, Junggar Basin, Xinjiang