中文摘要：

作为气候的干旱和放牧紧张的增加，灌木玩在在干旱、半干旱的区域的草地生态系统的一个日益重要的角色，和它的丰富通常也增加。然而，气候的干旱的效果和在草地的灌木的性复制上的放牧紧张仍然保持大部分不清楚。以便理解擦伤紧张和气候的干旱的效果灌木种类的种子生产上的应力，和他们的相互作用，我们在三放牧紧张下面检验了种子数字，种子重量和锦鸡儿属植物 stenophylla 的种子产量( fenced ，温和放牧并且严重放牧)越过在内部蒙古大草原的一个气候的干旱坡度(半干旱、干旱、很干旱、强烈地干旱的地区)，北中国在 2012-2013 期间。种子数字，种子重量和种子产量逐渐地增加了从对干旱地区半干旱，但是减少了从对在 fenced 情节的强烈地干旱的地区干旱。种子数字和种子收益减少了从对在因此，放牧提高了的温和、严重的放牧处理阴谋的强烈地干旱的地区半干旱 C 的种子生产上的气候的干旱的抑制效果。stenophylla。当放牧紧张增加了，种子数字和种子收益逐渐地减少了。种子重量在严重放牧阴谋是最高的，由温和放牧阴谋然后 fenced 阴谋列在后面。降水在学习时期期间 interannually 变化了。我们观察到种子数字，种子重量和种子产量比在高降水年(2012 ) 里在低降水年(2013 ) 里是更低的。作为增加的气候的干旱应力，在 C 的种子生产上放牧的否定效果。stenophylla 逐渐地也增加了。我们的结果显示气候的干旱应力可以贡献 C 的侵入。在由支持它的种子生产的干旱地区的 stenophylla 灌木。然而，放牧在 C 的性复制上有否定效果。stenophylla，和干旱应力的联合效果并且放牧严重压制了 C 的性复制。在强烈地干旱的地区的 stenophylla。

英文摘要：

As the increases of climatic aridity and grazing intensity, shrubs play an increasingly important role in grassland ecosystem in arid and semi-arid regions, and its abundance also generally increases. However, the effects of climatic aridity and grazing intensity on sexual reproduction of shrubs in grassland remain largely unclear. In order to understand the effects of grazing intensity and climatic drought stress, and their interaction on seed production of shrub species, we examined the seed number, seed weight and seed yield of Caragana stenophylla under three grazing intensities （fenced, mild grazing and severe grazing） across a climatic aridity gradient （semi-arid, arid, very arid and intensively arid zones） in the Inner Mongolia Steppe, northern China during 2012-2013. The seed number, seed weight and seed yield gradually increased from the semi-arid to the very arid zones, but decreased from the very arid to the intensively arid zones in fenced plots. The seed number and seed yield decreased from the semi-arid to the intensively arid zones in mild and severe grazing treatment plots, therefore, grazing enhanced the suppression effect of climatic aridity on seed production of C. stenophylla. The seed number and seed yield gradually decreased as grazing intensity increased. The seed weight was highest in severe grazing plots, followed by the mild grazing plots and then the fenced plots. Precipitation varied interannually during the study period. We observed that the seed number seed weight and seed yield were lower in the low precipitation year （2013） than in the high precipitation year （2012）. As climatic drought stress increased, the negative effects of grazing on seed production of C. stenophylla also gradually increased. Our results indicated that climatic drought stress may contribute to the encroachment of C. stenophylla shrub in arid zones by promoting its seed production. However, grazing had negative effects on sexual reproduction of C. stenophylla, and the combined effects of drought