| Phenotypic plasticity of plants is one of the hotspots of debate in genetics and plant morphology.Phenotypic structure of plants is of great significance to the evaluation of plant growth and development,the prediction of fruit yield,the mechanism of interspecific competition and the study of the degree to which plant morphological characteristics are affected by environmental conditions.Phenotypic plasticity of plants can be used to understand the genotype and plant morphology.The relationship between environments provides a basis for precision agriculture.In this paper,plant phenotypes were studied.Firstly,the status of research and application of three-dimensional scanning technology of lidar is introduced,and the advantages of lidar in obtaining plant phenotypic data are discussed.Secondly,nine plants with different morphological structures were selected to obtain plant phenotypic data by traditional phenotypic measurements,and the complete point cloud data of plants were scanned by lidar.The phenotypic data extracted from point cloud data were compared with the phenotypic data obtained by traditional measurements to verify the accuracy of the phenotypic data obtained by lidar.Subsequently,this paper designs an experiment on plant shade avoidance response,choosing a malignant invasive species,Solidago canadensis,as the experimental plant.According to the principle of shadeavoidance reaction,four different treatments are selected:transparent membrane treatment,green top transparent membrane treatment,green top transparent membrane treatment,green top transparent membrane treatment,all-green membrane treatment,four treatments simulate no competition,competition on the top,around and from all sides.The phenotypic structure of Solidago canadensis was monitored and scanned by lidar for three months.The monthly plant height,leaf shape,leaf angle and other phenotypic data were extracted from the point cloud data.The changes of phenotypic structure of Solidago canadensis under four shading conditions were analyzed.The results show that:(1)Lidar can extract plant phenotypes of various complex forms accurately.Compared with traditional measurement methods,the errors of leaf area,leaf inclination angle,azimuth angle,leaf spacing and petiole length were 95.16%,92.15%,91.81%,92.64%,93.95%,respectively.At the same time,manual angle measurement will also bring some artificial errors,which can not explain the inaccuracy of the data obtained by lidar.Compared with other measurement methods,the phenotypic data extracted by lidar has higher data accuracy.(2)In the shading experiment,there was no significant difference in plant height between the four treatments,but the plant height under the green film treatment was relatively high,reflecting the trend of plant slender growth.(3)In leaf morphology,the leaf area of Solidago canadensis showed significant difference in August.The leaf area under transparent treatment and green edge treatment was larger than that under the other two treatments.The leaf circumference and leaf area showed the same trend.Under shading conditions,the leaf area had a tendency to decrease,and the leaf length and width decreased significantly.Edge shading had a significant effect on leaf morphological growth of Solidago canadensis.(4)The results of leaf angle showed that the lateral shading had a significant effect on leaf inclination.Leaf Inclination under all-green treatment and top-green treatment was significantly higher than that under the other two treatments.Leaf inclination had a higher degree of contraction and less light was obtained.The reason may be that in order to reduce horizontal competition,the shrinking blade reduces the influence of shading on the blade.In the aspect of leaf rotation angle,there was significant difference between the top leaf rotation angle under green edge treatment and other treatments.The lower the degree of self-shielding of the upper part of the plant under this treatment,the plant adjusted according to its own situation,and the overall leaf rotation angle fluctuated up and down at 60°.(5)The ecological plasticity of Solidago canadensis is very strong.Even in the case of shading,the phenotype of Solidago canadensis can respond quickly to the environment,change its height,leaf area and leaf inclination angle,and obtain the maximum light resources.This is also one of the reasons for the successful invasion of this species.The study of shading response of Solidago canadensis can be used to predict its distribution range.To help formulate control programs for invasive plants. |
