| In this paper, the plant communities formed from the cypress artificial forest under the different transformation and regeneration models (named 10M,15M,20M,25M, Robinia pseudoacacia, Erythrina) were studied in the Yangtze River Forest Farm in Yunyang County of Chongqing Municipality. By combining the field investigation and the indoor experiment, The plant community structures, the species compositions, and characteristics of soil seed banks under different transformation and regenerated models were analyzed, The results were as follows.1. In this research, there were 68 vascular plant species,belonging to 62 genera and 40 families. Amounts of plant species from plant communities in the region had been affected significantly under the different transformation and regeneration models with obvious orders. There were 15 seed plant species in control community,belonging to 15 genera and 14 famlies. There were 18 species seed plant community in 10M transformation zone,belonging to 17 genera and 13 famlies. .There were 18 species seed plant community in 15M transformation zone,belonging to 18 genera and 11 famlies. There were 37 species seed plant community in 20M transformation zone,belonging to 31 genera and 19 famlies. There were 35 species seed plant community in 25M transformation zone, belonging to 30 genera and 22 famlies. There were 33 species seed plant community in Robinia pseudoacacia transformation zone, belonging to 33 genera and 21 famlies. There werer 34 species seed plant community in Erythrin transformation zone, belonging to 31 genera and 23 famlies. By contrast with their adjacent cypress forests, amounts of family, genera and species had declined in the transformation zone under 10M and 15M models. And others all had varying degrees of variations.2. In the shrub layer, species richness of plant communities increased obviously in the 10M, 15M, 20M, 25M transformation zone compared with the control,of which in 20M, 25M transformation zone was the highest, of which in Robinia pseudoacacia was identical with that in Erythrina, but species diversity of all transformation zones reduced more or less. Compared with their associated cypress forest, species richness of plant communities in 10M, 15M transformation zone was lower, which of 20M transformation zone was identical with, however that of 25M transformation zone were higher , Robinia pseudoacacia too, and Erythrina opposite. Only dominance in Robinia pseudoacacia was higher,but diversity,evenness and dominance indices in Erythrina exceeded that in their adjacent cypress forest.3. In the herb layer,species richness of plant communities in 10M,15M,20M,25M transformation zone were higher than the control communities, in which diversity, evenness, dominance indices distinctly were also higher. Species diversity in the herb layer the under the different transformation and regenration models was significantly affected , which of the different transformation zones had varying degrees of advance. Compared with their associated cypress forest, there was little change in species richness in the different transformation zones, the variation trend of species diversity , evenness and dominance indices was basically identical. Species diversity in Erythrina were lower , variations of which in Robinia pseudoacacia were out of order.4. A total germination included 28 species and 1169 seedlings which mainly were herbs, a small number of shrubs,belonging to 17 families and 23 genera in the soil seed bank germination trail. There were moderate reserves in the soil seed banks,between 120 and 915 grains·m-2, which were was higher than that of control. Within the top 0～15cm deep of soil, with soil depth increaseing,the seed bank density decreased. Within the top 0～2cm deep of soil,by contrast with control the seed bank density of soil in each plant community higher, which of 20M transformation zone was the highest, which of Erythrina was the highest among all their adjacent cypress forest and which of 20M,25M transformation zone only was the higher than that of their adjacent cypress forest. More obvious similarrity in species compositions of the soil seed banks in each plant community was was found with similarrity of 21.06% to 85.72%, which of transformation zones and their adjacent cypress forest was also found with similarrity of 16.67% to 80%.On the contrast,the values similarity coefficient between the soil seed banks and the aboveground vegetation were lower in all stand with the highest similarity coefficient only 37.04%.But the contribution of the aboveground vegetation was much bigger to the soil seed banks, seed amounts of the same species of both accounted for 63.84% in all the soil seed banks.
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