Chavarría-Krauser Andrés, Jäger Willi, Schurr Ulrich
ICG-III (Phytosphere), Research Center Jülich, 52425 Jülich, Germany.
Institute of Applied Mathematics, University of Heidelberg, INF 294, 69120 Heidelberg, Germany.
Funct Plant Biol. 2005 Sep;32(9):849-862. doi: 10.1071/FP05033.
Plant hormones control many aspects of plant development and play an important role in root growth. Many plant reactions, such as gravitropism and hydrotropism, rely on growth as a driving motor and hormones as signals. Thus, modelling the effects of hormones on expanding root tips is an essential step in understanding plant roots. Here we achieve a connection between root growth and hormone distribution by extending a model of root tip growth, which describes the tip as a string of dividing and expanding cells. In contrast to a former model, a biophysical growth equation relates the cell wall extensibility, the osmotic potential and the yield threshold to the relative growth rate. This equation is used in combination with a refined hormone model including active auxin transport. The model assumes that the wall extensibility is determined by the concentration of a wall enzyme, whose production and degradation are assumed to be controlled by auxin and cytokinin. Investigation of the effects of auxin on the relative growth rate distribution thus becomes possible. Solving the equations numerically allows us to test the reaction of the model to changes in auxin production. Results are validated with measurements found in literature.
植物激素控制着植物发育的许多方面，并在根系生长中发挥重要作用。许多植物反应，如向地性和向水性，都依赖于生长作为驱动动力，激素作为信号。因此，模拟激素对根尖生长的影响是理解植物根系的关键一步。在这里，我们通过扩展根尖生长模型，实现了根系生长与激素分布之间的联系，该模型将根尖描述为一串分裂和扩展的细胞。与之前的模型不同，一个生物物理生长方程将细胞壁伸展性、渗透势和屈服阈值与相对生长速率联系起来。该方程与一个包含活性生长素运输的改进激素模型相结合使用。该模型假设细胞壁伸展性由一种细胞壁酶的浓度决定，其产生和降解被认为受生长素和细胞分裂素控制。因此，研究生长素对相对生长速率分布的影响成为可能。通过数值求解这些方程，我们能够测试模型对生长素产生变化的反应。结果通过文献中的测量进行了验证。
