Ceratoides arborescens( Losinsk) Tsien et C. G. Ma is an important forage in the northwestern arid and semiarid regions of China. It has rich nutrient reserves,strong resistance to drought,and is also an excellent resource for ecological reconstruction and grassland improvement. In this study,the effects of pollen and resource availability on overall seed production in a natural population of C. arborescens were evaluated. The experimental material was taken from Siziwang Banner,Inner Mongolia,China. The plants were 4 years old,60 × 60 cm in size,and 10—200 cm in height.Experimental treatments included artificial pollination from different pollen sources,fertilizer addition,and different degrees of defoliation and deflowering,and the resulting seed set( seeds per plant),fruit set,and 1000-grain weight were determined. The selective abortion hypothesis and plant reproductive strategies were considered. The results were as follows: The pollen source and quality but not the total pollen numbers significantly affected the reproduction of this species. Pollens from different sources have significant impacts on fruit set,seed set,and 1000-grain weight. Selffertilization with pollen grains from the same inflorescence yielded 10. 04% fruit set,and fruit sets using pollen from a different inflorescence of the same plant and from different plants were 52. 16% and 65. 09%,respectively; the latter wassignificantly higher than in the control and the other treatments. The 1000-grain weight from fertilizations using pollen from different plants was 1. 970 g,which was significantly higher than in the control and in self-fertilizations using pollen from different inflorescences of the same plant and from the same inflorescence. The seed set in this natural population was nutrient limited. Externally supplied fertilizer increased the numbers of flowers,and increased the seed set(89. 96%) and1000-grain weight( 1. 879 g) significantly compared with the unfertilized control,Better nutrition can enhance female reproductive function,improving both seed yield and quality. We performed five leaf cutting treatments,including the control. As increasing percentages of leaves were cut,the seed set decreased; all of the leaf cutting treatments resulted in significantly lower seed set than in the control. As increasing percentages of leaves were cut,1000-grain weight also decreased; cutting of half,three-fourths,and all of the leaves resulted in significantly lower 1000-grain weights than in the uncut control. The flower removal experiment indicated that seed set increased significantly but 1000-grain weight decreased significantly as more flowers were removed. There was selective abortion in C. arborescens. Ceratoides arborescens has adopted dichogamous reproduction to avoid inbreeding depression; in the absence of complete fertilization by pollen from a different plant,the flowers can be self-fertilized,which may function as a breeding safeguard mechanism to ensure reproduction when exogenous pollen is scarce. Plants of this species also improved their seed set( to increase the potential number of offspring) and increased their seed size( to enhance the quality and competitiveness of their progeny) when resources were relatively abundant,both of which are strategies to improve fitness. The statistical analyses of fruit set,seed set,and seed weight indicated that C. arborescens has strongly plastic responses to pollen from different sources,to supplemental fertilization,and to the cutting of leaves and flowers. To maximize its fitness,plants of this species adjust their reproductive allocations,modes of pollination,and seed sets according to pollen and resource availability. Ceratoides arborescens has a complex reproductive strategy that provides it with great adaptability to its environment.