放牧强度对短花针茅草原冷蒿繁殖特性的影响

研究不同放牧强度下短花针茅(Stipa breviflora Griseb.)草原植物——冷蒿(Artemisia frigida Willd.)的种子繁殖和营养繁殖特性,探讨不同放牧强度下冷蒿繁殖方式的变化。结果表明:冷蒿在轻牧区和封育区单位面积种子产量较高,重牧条件下不能产生种子。冷蒿营养繁殖的各构件在轻牧区表现最好,轻度放牧能促进冷蒿的营养繁殖更新。放牧增加了冷蒿地下部分的投资而减少了地上部分的,这是其适应环境的对策。随着放牧强度的增加,冷蒿的生殖格局由种子繁殖和营养繁殖并存向单一的营养繁殖转变。

Effects of Grazing Intensity on Reproductive Characteristics of Artemisia frigida Willd.in Stipa breviflora Griseb. Steppe

This paper investigated the reproductive characteristics of Arternisia frigida Willd. from the aspects of both seed propagation and vegetative propagation under different grazing intensities in Stipa breviflora Griseb. steppe. The main research results are as follows. Seed production of A. frigida was high in light grazing and no-grazing plot and not observed under heavy grazing. The vegetative reproduction of A. frigida was accelerated by light grazing and the performances of all vegetative propagation components were better than other treatments. It seemed to be a strategy of A. frigida to increase the biomass alloca- tion to underground while decrease the aboveground part under grazing conditions. With the increase of grazing intensity, the reproductive pattern of A. frigida changed from coexistence of seed propagation and vegetative propagation to vegetative propagation alone.