Abstract: To understand the effects of fencing and grazing on Caragana tibetica seed production, the phenological period of sexual reproduction, the biomass and water content of flower, the quantities of flower and fruit of C. tibetica under fencing and grazing conditions were investigated respectively in the arid desert area of Inner Mongolia Plateau. Results showed that the phenological period of sexual reproduction of C. tibetica was not significantly different between fencing and grazing plots. The biomass of flower, the water content of flower, and the sexual reproduction input of flower were not significantly different between fencing and grazing plots, either. In contrast, The abortive rates during flowering and fruiting phases in the fencing plots were significantly lower than those in the grazing plots, with the former being about 30 times as much as the later (P<0.01). The quantities of young-fruit and ripe-fruit in the grazing plots were also significantly lower than those in the fencing plots (P<0.01). These results indicated that grazing might limit the seed production of C. tibetica mainly through reducing fruit-set rate.

Key words: Caragana tibetica, Phenological period, Seed production, Abortive rate, Fruit-set rate

摘要： 为掌握内蒙古高原荒漠区围封和放牧对垫状锦鸡儿（Caragana tibetica）种子产量的影响，通过野外定点调查统计了围封与放牧样地垫状锦鸡儿物候期、花朵参数、花朵数和果实数量。结果表明：围封与放牧样地垫状锦鸡儿物候无差别；花朵数、花生物量、花朵含水量和花朵有性繁殖投入在围封与放牧样地间无显著差异；围封样地花期败育率和果期败育率均极显著小于放牧样地（P<0.01），从而导致围封样地座果率为放牧样地的30倍（P<0.01）；放牧样地的幼荚果数和成熟荚果数均极显著低于围封样地（P<0.01）。这表明，放牧主要是通过降低座果率制约垫状锦鸡儿的种子产量。

关键词: 垫状锦鸡儿, 物候期, 种子产量, 败育率, 座果率