| To reveal the response mechanism and adaptation strategies of annual plants to environmental change in desert areas, the morphological structure, biomass allocation and its correlation with environmental factors of A. squarrosum in Minqin, Wuwei and Gulang were studied. The results showed that (1) The average annual temperature, sunshine duration and soil average daily temperature in Gulang were the lowest, which were 6.81℃, 2 669 h and 16.22℃, respectively, while Wuwei was the highest, which were 8.58℃, 2 873.4 h and 22.94℃, respectively. Soil water content, soil silt and soil available phosphorus in Gulang were the highest, which were 4.53%, 17.51% and 6.81 g·kg-1, respectively, while Minqin was the lowest, which were 1.46%, 7.19% and 5.55 g·kg-1, respectively. Gulang had the highest plant height, crown width and root length which were 70.63 cm, 54.24 cm and 96.15 cm, respectively, while Minqin were the lowest, which were 62.40 cm, 46.77 cm and 86.31 cm, respectively. (2) The biomass, mass fraction and root\|shoot ratio of Gulang were the highest, which were 7.56g、15.98% and 0.291. The biomass of root\|stem, root\|leaf, root\|flower, leaf\|stem, flower\|stem and flower\|leaf showed allometric relationships with α<1 in different habitats. (3) Plant height was significantly positively correlated with root, stem, leaf and flower biomass, and significantly negatively correlated with root\|shoot ratio in the three habitats. The root biomass and root shoot ratio were negatively correlated with average annual temperature and soil average daily temperature, and positively correlated with soil organic matter, total nitrogen, water content and silt. There were significant or extremely significant negative correlations between annual sunshine duration, annual total solar radiation and leaf and flower biomass. Therefore, the soil moisture content and fertility of Gulang habitat was better, and the growth of A. squarrosum was better. The morphological characteristics of A. squarrosum showed a trend of synergetic change with individual biomass. The accumulation rate of underground biomass was higher than that of aboveground biomass, and that of reproductive organs were higher than that of vegetative organs. |