Kirk Guy J D
Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK.
National Soil Resources Institute, Cranfield University, Silsoe MK45 4DT, UK.
New Phytol. 2003 Jul;159(1):185-194. doi: 10.1046/j.1469-8137.2003.00793.x.
• The characteristics of Oryza sativa roots required for internal aeration may conflict with those for efficient nutrient acquisition, particularly the surface area available for absorbing nutrients and the extent of oxygenation of the rhizosphere. • A model was developed for calculating the steady-state diffusion of O through a primary root and its laterals and the simultaneous consumption of O in respiration and loss to the soil. Results for a realistic set of parameter values were compared with available experimental data, and a sensitivity analysis given. • It was seen that a system of coarse, aerenchmymatous, primary roots with gas-impermeable walls conducting O to short, fine, gas-permeable laterals (i.e. the basic architecture of current rice genotypes) provided the greatest absorbing surface per unit aerated root mass. • With this architecture and typical rates of root respiration, rates of O loss to the soil can be sufficient to, for example, nitrify sufficient NH to NO to allow a plant to absorb half its N as NO , as well as to oxidize toxins such as Fe .
• 水稻根系内部通气所需的特性可能与高效获取养分所需的特性相冲突，尤其是吸收养分的表面积和根际的氧化程度。
• 建立了一个模型，用于计算氧气通过主根及其侧根的稳态扩散以及呼吸作用中氧气的同时消耗和向土壤中的损失。将一组实际参数值的结果与现有实验数据进行了比较，并进行了敏感性分析。
• 可以看出，由具有不透气质壁的粗大、通气组织化的主根组成的系统，将氧气输送到短而细、透气的侧根（即当前水稻基因型的基本结构），每单位通气根质量提供了最大的吸收表面积。
• 采用这种结构和典型的根系呼吸速率，向土壤中损失氧气的速率足以，例如，将足够的铵氧化为硝酸盐，使植物能够吸收一半的氮作为硝酸盐，以及氧化铁等毒素。
