基于定量描述的小麦根系构型及其与养分吸收利用的关系

The wheat root system is an important organ that supports the growth of above-ground and absorption of nutrients and water. The spatial distribution characteristics of wheat root system and its relationship with dense and fertilizer are important to guide wheat cultivation management. In this project, the quantitative acquisition, three-dimensional reconstruction and nutrient absorption and utilization of wheat root morphology were studied by field and soil column experiments. The research consists of three parts. The first is the spatial distribution characteristics and quantitative description of wheat root system. The differences of spatial distribution of wheat roots under different treatment methods are proved and quantified by image recognition technology. The second is the 3D morphological acquisition and real reconstruction of wheat root system. The three-dimensional information of wheat root system can be obtained by means of root in-situ monitor, laser handheld 3D scanner and other equipment, and these can realize 3D reconstruction and visualization of root spatial distribution. Thirdly, the relationship between the spatial distribution of wheat root system and nutrient absorption and utilization can be clarified, as well as the changes of nutrients in plants and soil, as well as changes in root morphology and physiological indexes. In field experiments, different varieties, densities and fertilizer levels were set. In the field, root system in situ monitor was used to obtain root system data in real time. The root system was dug and cleaned periodically. The laser hand-held 3D scanner was used to obtain three-dimensional information. And the root morphology and physiological indexes were measured. The soil columns were set to different fertilization depth and soil water content. The number and morphology of root system in transverse and longitudinal sections were quantitatively analyzed by two-dimensional image technique. The root system was regularly cleaned, as far as possible to keep the original shape, then the three-dimensional information was obtained and the morphological and physiological indicators were measured. In order to provide a reference for density and fertilizer management in the wheat production process, the content of N, P, K and other elements in soil and plant were measured in the main growth period of wheat in the experiments, and the changes of root architecture and its relationship with nutrient absorption and utilization in different ways were clarified combining with the 3D reconstruction scene of root development.

小麦根系是支撑地上部生长、吸收养分和水分的重要器官，明确其空间分布特征及其与密肥之间的关系，对指导小麦栽培管理有重要意义。本项目利用大田和土柱试验，对小麦根系形态的定量获取、三维重构及养分的吸收利用展开研究。其中大田试验设置不同的品种、密度及肥料水平，田间使用根系原位监测仪，实时获取根系数据，并定期（生育前期）将根系挖出洗净，用激光手持3D扫描仪获取三维信息并测量根系的形态和生理指标；土柱试验设置不同的施肥深度和土壤含水量，利用横向和纵向剖面分割方法，通过二维图像定量分析根系在不同方向上的数量及形态等，并定期（全生育期）将根系去土洗净（尽可能保持原状），获取三维信息并测量形态和生理指标。上述试验均在小麦主要生育时期测定土壤及植株体内N、P、K等元素的含量，结合根系发展的3D重构场景，明确不同处理方式下小麦根系构型的变化及其与养分吸收利用的关系，以期为小麦生产过程中的密肥管理等措施提供参考。

根系是支撑地上部生长、吸收养分和水分的重要器官，明确其空间分布特征及其与密肥之间的关系，对指导小麦栽培管理有重要意义。作物根系3D构型决定着根系的土体空间利用效率，也影响到水肥的空间搜索与根际竞争环境。不同的密、肥等措施影响小麦根系的分布与构型，这种几何结构可以通过图像分析的手段来定量化描述。而根系的几何结构与小麦的生长及肥料利用究竟有着什么样的关系，如何来定量描述小麦根系的几何特征并实现其3D重构对于群体结构分析具有积极意义。. 研究内容主要分成三部分，第一部分是小麦根系的空间分布特征与定量化描述，探明不同处理条件下小麦根系空间分布的差异，并利用图像技术进行定量化描述和分析；第二部分是小麦根系3D形态获取与真实重构，主要利用根系原位监测仪、激光手持3D扫描仪等设备获取小麦根系的3D信息，实现根系空间分布的3D重构及可视化；第三部分是小麦根系的3D结构与养分吸收利用的关系，理清植株、土壤中的养分变化以及根系形态、生理指标变化。结合大田与土柱试验，构建不同几何结构的麦苗群体，建立不同麦苗几何结构下对根系的影响的定量化描述方法，为田间麦苗根系状态诊断提供理论支撑。. 研究明确了不同品种及密度下小麦根系的空间分布特征以及不同肥料水平、施肥方式及施肥深度下小麦根系的空间分布特征。探明了小麦根系空间分布的定量化描述方法，包括根系信息提取方法、根系计数方法、根长和直径计算方法等，其测量值与计算值的R2均达到0.94以上。构建的植株地上部三维模型计算的叶长、叶宽、株高和叶面积与手动测量结果吻合程度很高，R2均在0.82以上。最终从根系空间分布特征与3D形态差异的角度来解析小麦根系发展与养分吸收利用的关系，为小麦高产栽培调控提供有效的参考和借鉴。