Effects Of Petroleum And Saline Alkali On Seed Bank Germination And Dominant Species Growth Of Common Communities In The Yellow River Delta

Coastal wetland has many unique and important ecological functions.However,over the years,degradation of wetlands cused by environmental pollution and other destruction urgent to be solved.Vegetation restoration of the wetland in the Yellow River Delta,with its special geographical location and national strategic position has been listed as the key content of ecological protection in Shandong Province during the 14 th Five Year Plan period.However,the research on wetland vegetation restoration in the Yellow River Delta is still in its infancy.There is a lack of theoretical research on wetland vegetation restoration under the stress of salinization and oil pollution in coastal wetlands,and relevant research still needs to be carried out.In this study,the soil seed banks of three common communities(Phragmites australis community,P.australis–Suaeda glauca community and Multi-species community)and five species(Setaria viridis,Suaeda salsa,Sonchus arvensis,Artemisia mongolica and Triarrhena sacchariflora)in the wetland of the Yellow River Delta were set up under different diesel concentration and salinity conditions to the effects of different stress conditions on community soil seed bank germination,seed germination of different species and plant growth in different combinations,and summarize the plant restoration strategies to deal with different soil conditions in the Yellow River Delta.The results show that:(1)For the community seed bank,0-2% salinity has a significant inhibitory effect on the number of species,seedling density and species diversity of the seed bank of Multispecies community;0-2% soil diesel concentration(corresponding to soil oil concentration ranging from 0-12.3%)had no obvious effect on the seed bank.The soil seed bank of P.australis community and P.australis–S.glauca community are suitable for vegetation restoration with soil salinity from 1% to 2% and soil diesel concentration from 0% to 2%(corresponding to soil oil concentration ranging from 0-12.3%).Multispecies community is suitable for wetland vegetation restoration with soil salinity from0% to 1% and diesel concentration from 0% to 2%(corresponding to soil oil concentration ranging from 0-12.3%).(2)In the seed germination stage,diesel and salt would reduce the germination rate and germination potential of the seeds of five common species,delayed the germination time of the seeds,and reduced the root length,stem length and leaf length of the seedlings.The interaction between diesel and salt makes the inhibition more serious.T.sacchariflora has the best tolerance to diesel,S.viridis and S.salsa have a certain tolerance,and S.arvensis and A.mongolica have the worst tolerance.(3)The root length,leaf length,leaf number,fresh weight and dry weight of S.viridis,A.mongolica and S.salsa had been reduced by 4% soil diesel concentration(corresponding to 24.6% of soil oil concentration).The root shoot-ratio and dry weight/fresh weight ratio were increased.The hydrophobic properties and biological toxicity of petroleum are the main reasons for limiting plant growth.The interspecific relationship among the three species and the diesel tolerance of A.mongolica lead to the relatively good vegetation restoration effect of the relevant species combination of A.mongolica.A.mongolica can be used as a key species for vegetation restoration in oil polluted wetlands in the Yellow River Delta.According to the results of this study,the application scenarios of vegetation restoration materials(seed banks and species of different communities)in the wetland of the Yellow River Delta are discussed and summarized.The seed bank has strong recovery ability and wide application range,so it is recommended to be used in more severe repair conditions.