基于GreenLab的油松结构-功能模型

 植物结构-功能模型(Functional-structural models, FSMs)将结构模型与过程模型结合起来, 用以描述环境机制驱动的植物生长, 输出植物的三维结构。GreenLab是一个近年来不断发展着的基于源-汇关系的通用植物结构-功能模型, 它多应用于农作物, 在树木方面的应用还很少。该文以幼龄油松(Pinus tabulaeformis)为研究对象, 首次将GreenLab模型应用到虚拟树木生长的研究中。采用破坏性取样, 实测了9株油松幼树的形态结构、拓扑结构和器官生物量信息, 根据拓扑编码体系组织数据。模型的直接参数是通过实测数据获得的, 隐含参数是利用非线性最小二乘法拟合反求获得的。对模型的假设进行了验证, 并对模型的模拟效果进行了评估, 结果表明: 节间总鲜质量、树木叶总鲜质量、节间鲜质量、节间长度观测值和模型模拟值建立的回归方程的决定系数在0.78~0.91之间, 因此该模型较真实地反映了油松的结构和生长过程。提出的树木结构和生物量测量及编码方法, 可作为针叶树建立结构-功能模型的参照。

A FUNCTIONAL-STRUCTURAL MODEL GREENLAB FOR PINUS TABULAEFORMIS

Aims Functional-structural plant modeling is concerned with the integration of architecture and resource allocation as aspects of plant function. It can depict the three-dimensional presentation of plants for use in analyzing individual tree growth and interactions between structural architecture and resource allocation in environments. Our objective was to parameterize and validate the func-tional-structural model GreenLab for young Pinus tabulaeformis to simulate its growth. Few studies have applied the GreenLab model to trees. Methods Destructive sampling was done to collect detailed data including structure and biomass measurements from 9 young P. tabulaeformis trees. We used the functional-structural GreenLab model that has been successfully calibrated for several crops. To extend its application in tree growth analysis, we validated the basic hypotheses of the model such as constant allometry rules and source-sink rela-tionships. Direct parameters were attained from the measurement data and hidden parameters of the model were calibrated using the generalized least squares method. Important findings Simulations of P. tabulaeformis growth based on the fitted parameters were rea-sonably accurate. The coefficients of determination of linear regression equations between observations and predictions ranged from 0.78 to 0.91. The topological code system was set up to analyze tree topo-logical structure for simulation. The calibrated parameters can be used to simulate and visualize 3D representation of pine trees. The methods for measuring tree topology and biomass and coding system can serve as a reference for the development of functional-structural models of coniferous trees.