结构与功能反馈机制下根系生长向性模拟

    Simulation of tropisms of root system growth based on feedbacks between functions and structures

    • 摘要: 借助于根系生长发育的功能-结构模型,模拟了根系生长的向地性、向水性与向肥性。研究中采用Voxel体元对根系生长的土壤区域进行离散化,并设定各Voxel元8个顶点的土壤含水量、养分浓度;采用根系功能-结构模型描述了不同生长周期下根系在三维土壤空间的生长;采用空间碰撞检测技术,确定各根元所占据的Voxel元,并以根元中点坐标与其所占据的Voxel元的各顶点距离倒数作为权重,计算根元生长区域的土壤平均含水量与养分浓度;利用三基点阻力法,计算得到土壤含水量、养分浓度对根元库强的校正系数,重新计算当前周期下根系可利用的生物量在组成根系的各根元中的分配,并调整根元的生长方向。最后,在设定的不同土壤含水量与土壤养分分布情景下,模拟了根系的空间生长与分布。模拟结果显示借助根系的功能-结构模型,在特定的情景下,能够模拟根系生长过程中的向地性、向水性与向肥性。根系在空间生长是一个复杂的过程,在特定的条件下,能够通过一定的农业措施,如灌溉、施肥,改变其空间生长与分布,使得作物高效地利用土壤水分、养分资源,从而实现可持续发展的生态农业

       

      Abstract: It is very important to quantitatively study spatial growth and distribution of root system in precision agriculture, which can optimize the use efficiency of soil water and nutrient,and minimize the impacts of fertilizer to ecological environment. However, the spatial growth and distribution of root system were influenced mainly by the growth direction of root individual which was induced by geotropism, hydrotropism and nutrient-tropism. The growth process of root system in 3D soil space was implemented using the root functional-structural model developed by the principles of GREENLAB. The regions in which root system grows and develops were discretized by 3D spatial voxels. Having defined the voxels, the soil moistures and nutrients of local area which surrounded the root segment could be calculated by spatial collision detection technique. After obtaining the soil moistures and nutrients, the electro-impedance functions were used to adjust the sinks, while the growth direction of each root segment generated in current growth cycle was recalculated by the adjusted functional and structural parameters. With the help of multi-needle data structure, the dynamic storing of new root segment and visiting of all root system in each growth cycle was implemented. Finally, given some scenarios of spatial moisture and nutrient distribution, the geotropism, hydrotropism and nutrient-tropism of growth and development of root system were realized in the homogenous soil using the visual way, in which the parameters were from literatures.

       

    /

    返回文章
    返回