Abstract: The growth patterns of leaf and stem decide the light capture pattern of plants and the acreage of the material exchange between plants and external environment, whereas the biomass allocation is a main approach to study the plant life history strategies. Taking the degraded alpine grassland in the upper reaches of Shiyang River, Gansu Province of Northwest China as a case, the method of standardized major axis (SA-M) estimation was adopted to study the effects of Stellera chamaejasme- stem size on the biomass allocation in leaf and stem, and on the leaf area supporting efficiency. There existed an allometric relationship between the stem dry mass and the LMA, individual leaf area, and leaf dry mass, with a SMA slope of 0.781 (95% confidence interval, CI=0.71-0.94), 0.824 (CI=0.77-0.95), and 0.856 (CI=0.79-0.99), respectively. The S. chamaejasme with bigger stem had higher leaf biomass allocation percentage and leaf area supporting efficiency, and in the meantime, had higher LMA, indicating that the bigger S. chamaejasme mainly adopted an adaptive strategy of high resource-use efficiency, while the smaller one mainly employed an adaptive strategy of fast growth.

Key words: Peanut, Early rice, Transpiration rate, Stomatal conductance, Water stress