中文摘要：

选择内蒙古典型草原羊草＋大针茅群落中的优势植物羊草、大针茅、冰草和冷蒿，采用多种数量化指标，分别比较一个生长季内的生长动态、绝对生长速率（AGR）、相对生长速率（RGR）。结果表明：植物地上生物量均呈S形增长，8月中旬达到最大值；主要生长季内受降水不足的抑制作用依次为羊草〉冰草〉大针茅〉冷蒿。羊草和冰草AGR均呈双峰曲线，大针茅呈三峰曲线，冷蒿呈单峰曲线。生长主要集中在中前期，AGR大小依次为冷蒿（0．099g·株^-1·d^-1）〉大针茅（0．029g·株^-1·d^-1）〉羊草（0．003g·株^-1·d^-1）〉冰草（0．002g·株^-1·d^-1）。RGR与AGR有相似的季节性变化，其中羊草、冰草、冷蒿RGR均呈单峰曲线，大针茅呈三峰曲线；生长季初期RGR均表现出最高，生长潜能较大，7月末至8月中旬呈现负值；4种植物的最大净积累效率依次为冷蒿（0．108g·株^-1·d^-1·g^-1）〉大针茅（0．064g·株^-1·d^-1·g^-1）〉羊草（0．055g·株^-1·d^-1·g^-1）〉冰草（0．042g·株^-1·d^-1·g^-1）。不同生活型的生长曲线及生长速率均存在较大差异，但同属于根茎型的羊草和冰草生长动态曲线明显相似。

英文摘要：

On a typical steppe of Inner Mongolia, the growth dynamics, absolute growth rate （ AGR）, and relative growth rate （RGR） of dominant species Leymus chinensis, Stipa grandis, Agropyron michnoi and Artemisia frigida in L. chinensis ＋ S. grandis community were investigated during growth season. The results showed that the aboveground biomass of the plants increased in the shape of ＂S＂, and got the maximum in mid August. The insufficient rainfall in main growth periods limited plant growth, and the impact was in the order of L. chinensis 〉 A. michnoi 〉 S. grandis 〉 A. frigida. AGR showed a curve with double peaks for L. chinensis and A. michnoi, three peaks for S. grandis, and single peak for A. frigida. Plant growth was mainly in the early and middle periods of growth season, and the AGR was A. frigida （0. 099 g · plant^-1 · d^-1 ） 〉 S. grand/s （0. 029 g · plant^-1 · d^-1 ） 〉 L. chinensis （0. 003 g · plant^-1 · d^-1 ） 〉 A. michnoi （0. 002 g · plant^-1 · d^-1 ）. RGR had a seasonal change similar to AGR, and showed a curve with single peak for L. chinensis, A. michnoi and A. was the maximum in the early period of growth frigida, and three peaks for S. grand/s. The RGA season, and negative in late July and The maximum net accumulation efficiency of biomass was in the order of A. mid August. （0. 108 g · plant^-1 · d^-1 · g^-1） 〉S. grandis （0.064 g · plant^-1 · d^-1 · g^-1） 〉 L. chinens/s （0.055g · plant^-1 · d ^-1 · g ^-1 ） 〉 A. michnoi （0. 042 g · plant ^-1 · d ^-1 · g ^-1 ）. There existed greater differences in the growth curve and growth rate among different life forms, but the growth dynamic curves of rhizomatous plants L. chinensis and A. michnoi were similar.