中文摘要：

在内蒙古典型草原退化的羊草＋大针茅（Leymus chinensis＋Stipa grandis）群落中,选择三种生活型（life form ）的植物羊草（L. chinensis）、大针茅（S. grandis）、洽草（Koeleria cristata）、冷蒿（Artemisia frigida）,采用多种数量化指标,对其在一个生长季内的生长动态、绝对生长速率、相对生长速率分别进行比较研究。结果表明：1. 植物地上生物量在整个生长季内均呈S型增长,羊草、大针茅和冷蒿均于8月中旬达到最大值,而洽草于7月中旬达到最大值;主要生长季内,生长受降水的抑制作用依次为：根茎型〉丛生型〉匍匐茎型,羊草〉大针茅〉洽草〉冷蒿。 2. 羊草、洽草绝对生长速率AGR均呈双峰曲线,大针茅呈三峰曲线,冷蒿则呈单峰曲线，AGR最大值依次为：匍匐茎型〉丛生型〉根茎型,冷蒿（0.09932 g·stem^-1·d^-1）〉大针茅（0.029533 g·stem^-1·d^-1）〉洽草（0.003293 g·stem^-1·d^-1）〉羊草（0.002407 g·stem^-1·d^-1）。3.相对生长速率RGR与绝对生长速率AGR有相似的季节性变化,羊草、冷蒿RGR均呈单峰曲线,大针茅呈三峰曲线,而洽草呈双峰曲线变化;生长季初期RGR均表现出最高,生长潜能较大,随后出现不稳定的状态,但总体趋势在逐渐下降,7月末-8月中旬呈现负值;最大净积累效率依次为：冷蒿（0.107926 g·stem^-1·d^-1·g^-1）〉大针茅（0.064325 g·stem^-1·d^-1·g^-1）〉羊草（0.055327 g·stem^-1·d^-1·g^-1）〉洽草（0.04797 g·stem^-1·d^-1·g^-1）。4.从四种植物的生活型来看,不同生活型的植物种,生长曲线及生长速率都存在很大的差异,但同属于丛生型的大针茅和洽草生长动态曲线却明显相似。

英文摘要：

It was studied that the growth dynamic, absolute growth rate（AGR） and relative growth rate（RGR） of plants in three life forms in a growing season according to many quantification indexes. These plants were Leymus chinensis, Stipa grandis,Koeleria cristata and Artemisia frigida in L. chinensis ＋ S. grandis degenerated community in the typical steppe of Inner Mongolia. The results were given as followings： 1. Aboveground biomasses of tested plants increased with the shape of “S” in a growth season and got a maximum in middle August for L. chinensis, S. grandis and Artemisia frigida ,and in middle July for K. cristata. Growth of plant was inhibited by rainfall in growth season and the turn of extent of inhibition was rhizomatous 〉 tussock〉 stoloniferous,and L. chinensis 〉 S. grandis 〉 K. cristata 〉 A. frigida. 2. AGR showed a double-peak curve for L. chinensis and K. cristata, three-peak curve for S. grandis and single peak curve for A. frigida. The maximum of AGR was stoloniferous 〉bush form〉rhizomatous,A, frigida （0.09932 g·stem^-1·d^-1）〉 S. grandis（0.029533 g·stem^-1· d^-1）〉K, cristata（0.003293 g·stem^-1 · d^-1）〉L. chinensis（0.002407 g· stem^-1 · d^-l）. 3. RGR was similar with AGR in season changing. RGR was single peak curve for L. chinensis and A. frigida,three-peak curve for S. grandis,and double-peak curve for K. cristata. The peak values of RGR were in the early of the growing season and ability of growing was great. But growing rate was not stable,and the extent of RGR decreased,there were negative values of RGR in the late of July and middle of August. The maximum of efficiency of the net accumulation was A. frigida （0.107926 g · stem^-1 · d^-1 · g^-1）〉 S. grandis（0.064325 g · stem^-1 · d^-1 · g^-1）〉L, chinensis（0.055327 g · stem^-1 · d^-1 · g^-1）〉K, cristata（0.04797 g · stem^-1 · d^-1 · g^-1）. 4. There was a great difference of growth curve and growth rates of plants in different life forms. However,S. grandis a