| Populus euphratica was the main arboreal vegetation in the Birkum Desert.Due to the scarce precipitation and strong evaporation in the hinterland of the desert,the seed germination of Populus euphratica was inhibited,and root sprouting had become the main way and means of plant reproduction and occupation of the niche,and was the basis of stability,spreading population and community.Taking the western Taklimakan Desert-Birkum Desert as the research area,using unmanned aerial vehicle(UAV)remote sensing to obtain the morphological parameters and distribution between parental tree and root sprouts of Populus euphratica.The physical and chemical characteristics of root sprouts of Populus euphratica was obtained by digging section and laboratory experiments.And the characteristics of Populus euphratica root sprouting were discussed in combination with other investigation factors,to provide scientific basis for studying the mechanism of Populus euphratica root sprouting and carrying out wind-proof and sand-fixing plants.This study drawn the following conclusions:(1)The morphological and spatial distribution characteristics of parental tree and root sprouts of Populus euphratica is extracted and analyzed by Arc GIS software.The morphological characteristics of root sprout of Populus euphratica were different by comparing the morphological parameters.There was a correlation between the morphological characteristics of parental tree and root sprouts of Populus euphratica.In terms of spatial distribution characteristics,the spatial distribution of parental tree and root sprouts of Populus euphratica in the Birkum Desert obeyed the aggregation distribution and random distribution,and the overall aggregation degree increasesed with the increase of the distance scale.The spatial distribution followed a northeast-southwest distribution pattern or a northwest-southeast distribution pattern.(2)The distribution depth of sprouting roots suitable for the occurrence and growth of Populus euphratica roots was 10～50cm.It was easy to produce root and sprout seedlings in the range of 1.5～3.0cm in diameter,and the length of root and shoot nodes of Populus euphratica was 0.96～24.33 m.(3)The root germination rate of Populus Euphratica was between 0.29 and 0.85,and the number of root germination was between 4.75 and 17 plants.The effect of parental tree morphology on root sprouting capacity was slightly less,root diameter had a strong influence on the number of root sprouts of Populus euphratica,a proper thickness of root diameter and sand burial were beneficial to the occurrence of Populus euphratica roots.(4)There are differences in soil temperature,soil water content,soil conductivity,and soil organic matter content in the different sampling area.In terms of soil temperature,the soil temperature at the root and tiller in the longitudinal direction increases with the increase in latitude,and the soil temperature at the root and tiller in the transverse direction decreases as the longitude decreases.In terms of soil water content,the soil water content at the root tiller closest to the parental tree is not necessarily higher than the soil water content at the root tiller farthest from the parental tree,which may be related to factors such as topography and burying depth.In terms of soil conductivity,in the direction of the transverse line,as the longitude decreases,the soil conductivity at the root and tiller will decrease;in the direction of the longitudinal line,the soil conductivity does not show a regular trend.The soil organic matter content at the root tiller closest to the mother tree was slightly higher than that at the root tiller farthest from the parental tree.The physical and chemical properties are not highly correlated with the morphological characteristics and root sprout ability of Populus euphratica.(5)Using the principal component analysis method to analyze the driving force factors of Populus euphratica root sprout in the Birkum Desert,the main factors that promote the root sprouting of Populus euphratica could be summarized as the parental tree morphology factor crown width factor,tree height factor,crown length factor and so on.Among them,the parent tree morphology factor was the most important and driving force factor. |
