Thickness Of Different Active Layers In Frozen Soil Area Study On Changes Of Endogenous Hormone In Vegetation

The Greater and Lesser Khingan Mountains are dominated by woodland.The highest elevation of the Greater Khingan Mountains is 1528 m,the lowest is 180 m,and the average elevation is 573 m.The elevation of the southeast of the Lesser Khingan Mountains is 800-1000 m,and the northwest is mostly lowland hills.Its latitude is high,and it is also affected by the Siberian high pressure,making it the coldest natural area in my country.The permafrost resources in the Greater Khingan Mountains are very rich,and the most obvious degradation of permafrost caused by global warming is the change in the thickness of the active layer,which in turn affects the growth of vegetation on it.Vegetation endogenous hormones are the most direct factors reflecting vegetation growth,germination and dormancy,and the thickness of the active layer directly reflects the degradation of permafrost.Therefore,it is of great significance to explore whether there is a relationship between the thickness of the active layer and the endogenous hormones of vegetation for the study of vegetation growth and permafrost degradation.In this paper,the Heihe,Huzhong and Wuyiling areas are used as the research areas for sample collection and active layer thickness measurement.Glutathione(GA),abscisic acid(ABA),auxin(IAA),and ethylene(ETH)were used as detection indicators to explore the environmental factors that affect the thickness of the active layer,and use variance decomposition analysis(VPA)to analyze the thickness of the active layer and other environmental factors The main results of the relationship with vegetation endogenous hormones are as follows:(1)From the analysis of the thickness of the active layer in the three places: the thickness of the active layer of the larch forest in Xing'an is larger than that of the birch forest.Its thickness is 95cm;the area with the shallowest active layer of the Xing'an larch forest is Wuyiling,whose thickness is 83cm;the largest area is Heihe,its thickness is 105 cm.The soil temperature and soil moisture have the greatest influence on the active layer in the Heihe region,and the latitude,longitude and elevation have the greatest impact on the thickness of the active layer in the Huzhong region.All environmental factors have an impact on the thickness of the active layer,and the most obvious ones are latitude,longitude and elevation.(2)From the results of hormone content,the GA content is as follows: Rhododendron Xing'an > Xing'an Larch > Cyphaxica > White Birch > Xing'an Larch >Duscube bilberry > sedge.The content of IAA was as follows: Xing'an larch > white birch > bilberry > small leaf chapter > Xing'an rhododendron > lichen.The size of ETH content is as follows: bilberry dus > small leaf chapter > xing'an larch > xing'an rhododendron > white birch > moss.(3)According to the analysis results of the VPA model,the interpretation degree of the active layer thickness on the endogenous hormone content of vegetation is the largest among the environmental factors including latitude,longitude,elevation,active layer thickness,soil temperature,soil moisture,etc.The thickness of the active layer has a great influence on the content of endogenous hormones in vegetation.(4)According to the interpolation of the thickness of the active layer in the Wuyiling area,the thickness of the active layer in the Wuyiling area is mostly between80cm-120 cm,and the thickness of the active layer in a few areas can reach120cm-150 cm,<80cm,and even in some areas Frozen soil can be seen at about 40 cm.And according to the distribution map of plant endogenous hormones and the distribution map of active layer thickness,it can be seen that there are different degrees of correlation between the four vegetation endogenous hormones and the active layer thickness of the six typical vegetation.