Abstract: With field investigation and laboratory analysis, the relationships of plant diversity with carbon and nitrogen pool composition in four typical grassland ecosystems including warmtemperate tussock (WT), warmtemperate shrub tussock (WS), tropical tussock (TT) and tropical shrub tussock (TS) in Henan Province were explored through redundancy analysis (RDA). The results showed that plant species diversity in the shrub tussocks was higher than that of the tussocks. The plant functional groups in Henan grasslands were conformed to the regional characteristics. The proportion of C3 plants was much higher than that of C4 plants, while the weeds accounted for 64%-73%. The proportion of plant species with sexual and asexual reproduction patterns was up to 49%-56%. The composition of life forms was complex. Warm grassland was dominated by perennial herbs and shrubs, and tropical grassland was dominated by annual orbiennial herbs and perennial herbs. The results of RDA analysis showed that nitrogen density in the vegetation of WT and WS was positively correlated with Shannon and Pielou indices. Community carbon density was negatively correlated with soil nitrogen density and Shannon and Pielou indices. There was a positive correlation between carbon and nitrogen density and species richness of TT, a positive correlation between soil nitrogen density and Shannon and Pielou indices, and a negative correlation between vegetation nitrogen density and Shannon and Pielou indices. Soil carbon and nitrogen density of TS was positively correlated with Shannon index, and community carbon and nitrogen density was negatively correlated with species richness and Shannon index. That is, species diversity and vegetation composition of different grassland types co-affected carbon and nitrogen density of vegetation and soil. The composition of carbon and nitrogen pools in Henan grassland ecosystems was the result of a combination of plant species abundance and distribution uniformity.

Key words: Bt corn, Bt protein, soil nutrient.