Study On Natural Regeneration And Adaptability Of Seed Germination Of Tetraena Mongolica

Tetraena mongolica is a rare and endangered plant on Ordos Plateau,which is a tertiary ancient mediterranean relict plant and has important academic research value.The relationship between soil seed bank and population regeneration was studied by studying the characteristics of soil seed bank in the core area of Tetraena mongolica.Based on the investigation of the seedling density,the distance of forest edge,the distribution density and distribution pattern of seedlings under different populations,the regeneration rule was analyzed.The effects of different soil water content and sand burial thickness on seed germination and emergence of Tetraena mongolica were studied,and the adaptability of seed germination was discussed.The results are as follows:(1)There were 7 species belonging to 6 families and 7 genera in the seed bank of Tetraena mongolica,including 1 species of shrubs and 6 species of herbs.density increased with depth of soil reduced.The comprehensive similarity coefficient between soil seed bank and aboveground vegetation was low.Judging from the comprehensive similarity coefficient,using soil seed bank to restore ground vegetation can show the limited variety of plants.(2)Tetraena mongolica mound is full of northwest winds throughout the year,and the results showed that the distribution of seedling was the southeast>northeast>southwest direction,and the results showed that wind direction was the dominant factor in affecting the seedling distribution;The seedling in Wujiamiao,Taosisu,Dishan and Qipanjing were aggregation distributionon the whole,and the population of Hainan showed only aggregation distribution at the scale of 5-7m.The other scales(1-5m and 7-10m)showed random distribution;In the 5 plots of the survey,there were two types of spatial correlation and non-correlation,which indicated that there was no effect on the spatial relationship between seedlings and mature trees.The reason for the difficulty of population renewal is not due to intraspecific competition.(3)When the sand thickness exceeded 2cm,Tetraena mongolica seed did not appear.According to the interaction analysis of soil moisture content and sand burial thickness,the soil water content and sand burial thickness had significant effects on the seedling emergence rate of Tetraena mongolica(P<0.05).Soil moisture content on 20%and sand buried thickness on 0.5cm was the most suitable environment for Tetraena mongolica seed germination and emergence.