Explication of speciffic function of crop root system components differing in development and anatomy

作物根系由发育和解剖特征不同的根组成。本研究的目的是探讨这些根之间的功能差异。首先，我们发现，在水稻根系中，除了常规的发育分析外，量化根系结构复杂性的分形分析和量化分枝模式的拓扑分析对于表征根系结构是非常有效的。在根中，侧根对土壤水分条件和离体培养条件的变化有明显的响应。碳、氮动态以及琥珀酸脱氢酶和过氧化物酶活性随老化的变化表明，种子根轴和侧根的老化模式不同。内源脱落酸和玉米素核苷的动态也存在差异。对几种食用豆类植物根系结构的研究表明， 关于我们 N主要通过侧根的发育而存在，主根的伸长生长在不同条件下表现出可塑性。花生根系中，侧根上形成的丛枝菌根较多，主根轴上很少形成丛枝菌根。在这些侧根上，菌根菌落发生增加acropetally特别是在相对老的根，开始在主根轴的近端部分。此外，菌根的形成通过侧根的发育改变了根系的形态，其中一级侧根和二级侧根的反应不同。因此，通过对根系中根成员的年龄进行表征，本研究表明，根系之间存在功能差异，如对各种环境因子的发育反应，代谢和生理活性，与菌根真菌的亲和性，它们通过发挥其特定的作用而有助于整个根系的整体功能。少

A crop root system consists of roots differing in developmental and anatomical features. This study aimed to examine functional difference among those roots.First, we showed that in rice root system, in addition to the conventional developmental analysis the fractal analysis that quantifies the complexity of root system structure and the topological analysis that quantifies the branching pattern are quite effective for characterizing root system structure. Then, among the roots, rspecially lateral roots were shown to sharply respond to the changes in moisture conditions in soil and culture conditions in vitro. Carbon and nitrogen dynamics, and changes in succinic dehydrogenase and peroxidase activity with aging indicated that seminal root axis and its lateral roots differ in aging pattern. The differences were also found in the dynamics of endogenous abscisic acid and zeatin riboside. An examination of root system structure for several food legume species revealed that genetic variatio … More n exists mainly due to lateral root development, and their taproot elongation growth exhibits plasticity when grown under different conditions. In a peanut root system, arbuscular mycorrhiza was formed mostly on lateral roots, but scarcely on taproot axis. On those lateral roots, the mycorrhizal colony occurrence increased acropetally especially in relatively aged roots that initiated on the proximal portion of the taproot axis. Further, the formation of mycorrhiza altered root system morphology through lateral root development, where the responses differed between 1st and 2nd order lateral roots.As such, through characterizing root members in a root system with a special attention to their ages, this study showed that the functional differences exist among the roots such as developmental response to various environmental factors, metabolic and physiological activity, and affinity with mycorrhizal fungus, and they contribute to the overall function of an entire root system by playing their specific roles. Less