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将水稻(Oryza sativa L.)根系区域分为根毛区域和根毛外区域,用米氏动力学方程描述主根和根毛表面对磷酸盐的吸收,把根毛磷酸盐的吸收作为扩散方程的源汇项,在Kirk模型的柠檬酸盐和磷酸盐的相互作用机制基础上,建立水稻根系吸收磷酸盐模型.利用该模型探讨水稻主根分泌柠檬酸盐对根系吸收磷酸盐的影响.数值模拟的结果表明,在根毛区域,液态磷酸盐浓度存在梯度变化;在根毛外区域,液态磷酸盐浓度低于Kirk模型,最大低于1.839μmol·L-1;水稻主根分泌柠檬酸盐的含量随着生长时间的增大而增加,然后保持不变;柠檬酸盐促进固态磷酸盐从土壤颗粒表面中解吸出来;在根毛生长的初期,主根吸收液态磷酸盐强于根毛,在16 h后,根毛吸收液态磷酸盐在水稻根系吸收中占主导作用.主根分泌柠檬酸盐和根系形态共同决定水稻根系对磷酸盐的吸收量.
The roots of rice (Oryza sativa L.) were divided into root hairs and root hairs. The Mie kinetic equation was used to describe the absorption of phosphate on the surface of root and root hairs. The absorption of root hair phosphate was used as the source and sink term of the diffusion equation. Based on Kirk’s model of interaction between citrate and phosphate, a model of rice root phosphate uptake was established. The model was used to investigate the effect of citrate secretion from root rhizosphere on phosphate uptake in roots. Numerical simulations showed that, In root hair area, the concentration of liquid phosphate varied with gradient. In the root hair area, the concentration of liquid phosphate was lower than that of Kirk model and the maximum was lower than 1.839 μmol·L-1. The content of citrate secreted by main roots of rice increased with the growth time Citrate promoted the desorption of solid phosphate from the soil particle surface. In the early stage of root hairs growth, the main root absorbed more liquid phosphate than root hairs. After 16 h, the root hairs absorbed liquid phosphate in rice Root absorption plays a leading role in the main root of the secretion of citrate and root morphology determine the rice root phosphate uptake.