根系发育的营养调控及对其生境的影响

根系发育对土壤中无机营养的供应和分配的变化非常敏感,本文综述了N、P、K等营养影响根系的发育进程如分枝、根毛产生、直径、生长角度、结瘤作用和簇生根的形成等的机制。营养的供应对根系发育的影响既可以是直接的、是外部营养浓度改变的结果、也可以是间接的、是植物内部营养状况变化的结果。直接途径引起暴露在营养供应中的那部分根系的发育反应;间接途径引起系统的反应,并且似乎依赖于来自冠部的长距离的信使。讨论了最新所了解的内外营养感受(sensing)的机制,长距离信号的可能特征,激素在营养形态发生反应中的作用,根系性状的基因型差异和遗传特性,以及植物根系在生态恢复、防止环境污染、全球气候变化和资源可持续发展中的作用。     

The nutritional control of root development

Root development is remarkably sensitive to variations in the supply and distribution of inorganic nutrients in the soil. Here we review examples of the ways in which nutrients such as N, P, K and Fe can affect developmental processes such as root branching, root hair production, root diameter, root growth angle, nodulation and proteoid root formation. The nutrient supply can affect root development either directly, as a result of changes in the external concentration of the nutrient, or indirectly through changes in the internal nutrient status of the plant. The direct pathway results in developmental responses that are localized to the part of the root exposed to the nutrient supply; the indirect pathway produces systemic responses and seems to depend on long-distance signals arising in the shoot. We propose the term `trophomorphogenesis' to describe the changes in plant morphology that arise from variations in the availability or distribution of nutrients in the environment. We discuss what is currently known about the mechanisms of external and internal nutrient sensing, the possible nature of the long-distance signals and the role of hormones in the trophomorphogenic response.