玉米茎秆木质部表型检测及多尺度水分运输动力学仿真研究

Xylem phenotypes of maize stem are directly related with its water use efficiency, thus it is of great significance to set up multi-scale parametric xylem model of maize stem and dynamic simulation model for water transport in the evaluation of water use efficiency and varieties screening of drought resistance. With xylem phenotype detection of maize stem as the breakthrough point, multi-scale 2D and 3D datasets of maize plant – stem - xylem are obtained using 3D laser scanner, CT imaging and light microscopy imaging techniques, and used to analysis systematically the phenotypic parameters which are helpful to reveal the quantitative relationship between phenotypic parameters of xylem structures and its efficiency of water transport. Using object oriented technologies, maize multi-scale xylem model of maize stem is then built according to detected phenotypic parameters. Taking simplified maize root water absorption and canopy transpiration models as water exchange interfaces between plant and environment, dynamic model based on porous media is developed to dynamically simulate water transport in maize stem. By comparative analysis of phenotypic differences and water transport efficiency between maize varieties with drought-resistant differences, drought resistance evaluation method and software based on the xylem phenotype parameters of maize stem is proposed, and phenotype detection and water transport simulation software are provided. This project is beneficial to reveal water transport mechanism of maize, and provide technical support for xylem phenotype detection, selection and identification of drought-resistant varieties, and the measures of agronomic water saving.

玉米茎秆木质部表型与其水分运输功能直接相关，建立玉米茎秆木质部参数化模型及水分运输动力学模型，对不同基因型玉米的水分利用效率评价、抗旱性筛选等具有重要意义。课题以不同抗旱性玉米品种的茎秆木质部表型检测为切入点，利用激光三维扫描仪、CT成像和显微成像技术分别获取玉米植株-茎秆-木质部各尺度上二维/三维数据，系统解析玉米茎秆木质部表型参数，揭示木质部表型与抗旱性之间关系；进而，利用面向对象技术建立玉米茎秆木质部的多尺度模型，利用简化的玉米根部水分吸收和冠层蒸腾模型构造植物与环境的水分交换界面，基于多孔介质模型实现玉米茎秆水分运输动态模拟；最后，比较不同抗旱性玉米品种之间茎秆木质部的表型差异及其水分运输效率，为基于玉米茎秆木质部表型参数的抗旱性评价提供表型检测方法和仿真工具。课题实施有助于揭示玉米水分运输机理，为玉米木质部表型检测、抗旱性品种筛选与鉴定、及农艺节水提供技术支撑。

玉米茎秆木质部表型与其水分运输功能密切相关，本项目旨在从茎秆-维管束-木质部尺度探索玉米茎秆木质部表型检测、多尺度建模及玉米抗旱性评价方法。主要研究成果包括：针对单株数据原位测量、茎秆CT成像质量、显微切片染色等难点问题，提出玉米植株-茎秆-维管束-木质部多尺度数据采集规程，以保证玉米茎秆木质部表型检测和建模的数据质量；提出了基于Micro-CT和玻片扫描仪的玉米茎秆显微图像分析方法，构建茎秆维管束目标检测和语义分割模型，自动计算茎秆横截面上维管束/木质部33项表型参数，并开发了系列维管束/木质部表型分析软件；提出了基于旋转台成像和激光扫描的玉米单株尺度表型测量方法，构建植株茎秆、叶片、穗的语义分割模型，获取玉米植株、茎和器官尺度表型参数，开发了配套植株与器官表型分析软件；利用面向对象技术建立玉米茎秆木质部多尺度模型，分析了不同抗旱性玉米品种之间茎秆维管束/木质部的表型差异及其水分运输能力。本项目的研究成果有助于揭示玉米水分运输机制，为玉米木质部表型检测、抗旱性品种筛选与鉴定提供理论依据和数据支持。