Extraction Of Plant Root Architecture And Topological Parameters Based On 3D Visualization Model

The spatial configuration of plant root system has important theoretical and practical significance for plant growth and development,nutrient absorption,slope protection plant selection and soil reinforcement and slope protection.However,due to the influence of technical means and soil media,previous studies on roots were rough and not intuitive enough.In this paper,six common native plants of Artemisia scoparia,Artemisia giraldii,Ziziphus montana,Sophora davidii,Ulmus pumila and Robinia pseudoacacia in the loess area of northern Shaanxi were studied.The three-dimensional coordinates of the root system were obtained by using the three-dimensional motion tracker,and the three-dimensional visualization modeling of the plant root system was carried out according to the root diameter combined with the three-dimensional modeling software sketchup,and the reliability of the three-dimensional visualization modeling of the root system was verified.The laser handheld3D scanner(Free Scan UE)was used to scan the aboveground part of the plant to obtain the point cloud data.Combined with the software of the device and the 3ds Max drawing software,the 3D visual modeling and rendering of the aboveground part of the plant were realized.The root architecture parameters of plants under different slope conditions were compared and analyzed,the fractal dimension and topological index were calculated,and the root division methods of different plant root types were compared.;and the distribution of shear enhancement effects in the rhizosphere of different slope protection plants was explored.In order to reveal the ecological adaptability of plant roots under environmental heterogeneity conditions,and provide scientific basis for subsequent plant root research and ecological environment restoration.The main results are as follows:(1)The three-dimensional visualization models of aboveground parts and roots of plants were constructed respectively,which were realistic and truly restored the morphology and parameters of plants.According to the data extracted from the three-dimensional visualization model of roots and the measured data,the regression analysis of the three-dimensional modeling model of roots(R~2>0.9735)showed that the model was true and reliable.The application of three-dimensional visualization model of six plants was briefly described.(2)The root biomass of six plants showed a decreasing trend with the deepening of depth.The root horizontal distribution of Artemisia scoparia,Ziziphus spinosa and Robinia pseudoacacia was dominant,and the root vertical distribution of Artemisia giraldii,Sophora viciifolia and Ulmus pumila was dominant.The root topology of Artemisia scoparia,Ulmus pumila and Sophora viciifolia was very close to the fishtail branch structure,and the root topology of Artemisia giraldii,Ziziphus spinosa and Robinia pseudoacacia was very close to the forked branch structure.The fractal dimension of Artemisia giraldii and Artemisia scoparia was higher than Sophora viciifolia,Ziziphus spinosa,Ulmus pumila and Robinia pseudoacacia,while the fractal abundance was lower than Sophora viciifolia,Ziziphus spinosa,Ulmus pumila and Robinia pseudoacacia;the total root branching rate of the six plants was in the order of Robinia pseudoacacia,Artemisia giraldii,Ziziphus spinosa,Artemisia scoparia,Ulmus pumila,Sophora viciifolia,and the layer-by-layer branching rate had a similar change rule,based on principal component analysis.The root architecture parameters such as fractal index,topological index,total branching rate,stepwise branching rate,reduction coefficient,root width,root depth,root biomass,average root diameter,first-order lateral root and main root branching angle can well represent the root architecture characteristics of six loess plants in northern Shaanxi.At the same time,slope has a certain influence on root architecture parameters.(3)The shear strengthening effect of typical plant roots represented by Artemisia scoparia、Sophora davidii and Robinia pseudoacacia in the loess area of northern Shaanxi was analyzed.It was found that the maximum soil fixation effect of Artemisia scoparia,Sophora viciifolia and Robinia pseudoacacia all appeared in the soil surface layer(0-20cm),of which Artemisia scopari was 26.56 k Pa,Sophora davidii was 11.26 k Pa,and Robinia pseudoacacia was 19.27 k Pa.With the increase of soil depth,the increase of shear strength of Artemisia scoparia、Sophora davidii and Robinia pseudoacacia roots to soil decreased gradually.According to the three-dimensional solid visual digital model and size of six kinds of plant roots in the loess area of northern Shaanxi,the configuration of the same plant and different plants in soil consolidation and slope protection was analyzed.In this paper,the combination of layer-by-layer cleaning and three-dimensional digital instruments was used to study the plant roots,and the laser handheld three-dimensional scanner(Free Scan UE)was used to scan the aboveground parts of the plant.Finally,the three-dimensional entity digital visualization modeling of the whole plant was successfully realized.By accurately and truly restoring the three-dimensional characteristics of plant roots,we can quickly and easily extract the parameters of root configuration and compare the configuration and topological characteristics of different slope protection plant roots.The results of this study are expected to provide a theoretical basis for subsequent research on plant root architecture and vegetation configuration mapping for soil and water conservation design,landscape and horticultural planning.