| Mine wasteland is a kind of extreme ecosystem,which has the characteristics of high content of heavy metal and low soil fertility.It is difficult to restore vegetation.Soil seed bank technology is a good method for vegetation restoration in mining area.In this study,four types of vegetation(Broussonetia papyrifera shrub,Cleome viscosa shrub,Koelreuteria paniculata forest and Cynodon dactylon)were identified through seed bank germination test,fertilization and seed germination test in the waste land of Xiangtan manganese mine.Based on the characteristics of soil seed bank,the seed germination characteristics of main plants in soil seed bank and the effects of soil matrix and fertilization on seedling growth in soil seed bank were studied.The main results are as follows:(1)The results of seed bank germination test showed that comparing with the control community,the number of species(35 vs.27,16,3),species diversity index(H':2.57 vs.1.90,1.92,0.05),D:0.90 vs.0.74,0.74,0.02)of soil seed bank of manganese ore restoration communities(Cleome viscosa shrub,Koelreuteria paniculata forest and Cynodon dactylon)were lower than those of the control community.The similarity index of soil seed bank of each community ranged from 0.23 to 0.48.(2)The results of seed germination test showed that the plant height,aboveground biomass and hundred-grain weight of 17 plant species from mining area provenances were lower than those from non-mining area.Under the condition of no manganese stress,the germination rate of 17 species from both mining and non-mining provenances was the highest,accounting for 47.06%and 64.71%of the total species,respectively.When the concentration of manganese was 15000 ?mol/L,the fruit types,dispersal mode and aboveground biomass of 17 species from mining and non-mining provenances had no significant effect on germination rate,germination index and germination duration(P>0.05).There was a significant positive correlation between seed size and germination rate and total biomass(P<0.05),but no significant correlation between seed size and germination index,germination duration and root-shoot ratio(P>0.05).There was a significant positive correlation between seed size and total biomass of 17 species in non-mining area(P<0.05),but there was no significant correlation between seed size and germination rate,germination index,germination duration and root-shoot ratio(P>0.05).(3)The results of pot experiment of soil seed bank in mining and non-mining area showed that nitrogen addition had no significant effect on the species diversity of soil seed bank in mining area(P>0.05),but significantly increased the species diversity of soil seed bank in non-mining area(P<0.05).In the absence of nitrogen addition,the species diversity of soil seed bank in mining and non-mining area is based on the non-mining soil as matrix>mixed soil as matrix>mining soil as matrix.(4)Pot experiment results showed that nitrogen fertilizer addition significantly increased the total biomass of soil seed bank community,the total biomass of dicotyledons and monocotyledons,aboveground biomass,underground biomass and dominant species biomass in both mining and non-mining area(P<0.05).Under different soil matrix,the total biomass of soil seed bank population,the total biomass of dicotyledons and the biomass of dominant species were all non-mining soil as matrix>mixed soil as matrix>mining soil as matrix.The results show that fertilization can increase the biomass of plant and promote the growth of plant in soil seed bank of mining area,but have no significant effect on species diversity;fertilization can increase the species diversity and biomass of plant in non-mining area.Soil seed bank based on non-mining soil significantly increased plant biomass.Therefore,the ecological environment of the mining area can be improved by fertilizing and improving the soil matrix,and the growth of plants in the mining area can be promoted. |
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