| The study of natural herbivory and pot experiments was conducted to understand the laws of reproductive allocation and life history in two clonal plants in Kobresia humilis meadow by investigating the reproduction performance, vegetative growth performance and storage performance. And we proposed the main factors that influenced the laws of reproductive allocation in two clonal plants were grazing disturbance, resource availability and intraspecific competition and discussed the life history of clonal plant. Under different grazing intensities, gramineous grass: Elymus nutans is a caespitulose clonal plant, and subdominant herbs: Potentilla anserina is a stoloniferous clonal plant, which were experienced the different defoliation in K. humilis meadow from 1998 to 2002. In 2003, and we also let E. nutans and P. anserina experience different resource availability levels and different intraspecific competition levels in pot experiment. We collected data in a grazing experimental fenced plot that divided into four grazing treatments from 1998 to 2002 and a pot experiment that was designed random complete design (fertilizer × light × ramet density) in 2003. The difference and relative variation of reproduction performance, vegetative growth performance and storage performance were analyzed and compared between treatments in grazing experiment and pot one. The results could be summarized as follows:1. In grazing experiment, the difference among treatments for reproduction performance, vegetative growth performance and storage performance was significant in the caespitulose clonal plant——E. nutans. And the number of tiller, overground mass, belowground mass, sexual reproduction mass and sexual reproductive efforts were all the maximum in the light grazing intensity. This indicated that appropriate grazing disturbance would be in favour of the fitness obtained.2. In grazing experiment, the difference among treatments for reproduction performance, vegetative growth performance and storage performance was significant in the stoloniferous clonal plant——P. anserina. And the number of lamina, the length of stolon, overground mass, sexual reproduction mass, upported by the National Science Foundation of China. (No.39960053)sexual reproductive effort and clonal growth effort (or vegetative reproductive effort) were all the maximum or upper value in the medium and heavy grazing intensity. This indicated that definite grazing disturbance would be in favor of the fitness obtained.3.In pot experiment, E. nutans and P. anserina were obvious response to resource availability and instraspecific competition. And reproduction performance, vegetative growth performance and storage performance were all obvious enhancement with resource availability improvement. Reproductive outputs and ability were enhanced with intraspecific competition increasing in E. nutans. But in P. anserina clonal growth outputs and ability were enhanced with intraspecific competition decreasing. The absence of soil nutrition promoted the biomass allocation transferring to storage in E. nutans. Light was the main limited factor that restrained reproduction (including sexual reproduction and clonal growth) of the two clonal plants. 4.The relationship of mutual competitive organs is often trade-off. In various environments, the trade-off between sexual reproductive allocation and storage allocation occurred in E. nutans and P. anserine. And the trade-off between clonal growth allocation (vegetative reproductive allocation) and sexual reproductive allocation also occurred in E. nutans and P. anserine. Meanwhile the trade-off between clonal growth allocation and storage allocation occurred in P. anserine only when the environmental factor was light. In addition, we demonstrated that the sexual reproduction is size-dependent in E. nutans, and the sexual reproduction is higher cost than vegetative reproduction in P. anserine. 5.The difference of architecture of two clonal plants lead to the variance that the plants are in response to grazing distu...
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