Forde Brian G
Department of Biological Sciences, Lancaster University, Lancaster, LA1 4YQ, United Kingdom.
Annu Rev Plant Biol. 2002;53:203-24. doi: 10.1146/annurev.arplant.53.100301.135256.
Nitrate is the major source of nitrogen (N) for plants growing in aerobic soils. However, the NO3- ion is also used by plants as a signal to reprogram plant metabolism and to trigger changes in plant architecture. A striking example is the way that a root system can react to a localized source of NO3- by activating the NO3- uptake system and proliferating lateral roots preferentially within the NO3(-)-rich zone. That roots are able to respond autonomously in this fashion implies the existence of local signaling pathways that are sensitive to local changes in the external NO3- concentration. On the other hand, long-range signaling pathways are also needed to modulate these responses according to the plant's N status and to coordinate the allocation of resources between the root and the shoot. This review examines these signaling mechanisms and their interactions with sugar-sensing and hormonal response pathways.
硝酸盐是在有氧土壤中生长的植物的主要氮源。然而，硝酸根离子也被植物用作一种信号，来重新编程植物代谢并引发植物形态的变化。一个显著的例子是根系对局部硝酸根源的反应方式，即通过激活硝酸根吸收系统，并优先在富含硝酸根的区域内使侧根增殖。根系能够以这种方式自主做出反应，这意味着存在对外部硝酸根浓度局部变化敏感的局部信号通路。另一方面，还需要长距离信号通路来根据植物的氮素状况调节这些反应，并协调根和地上部分之间的资源分配。本文综述了这些信号传导机制及其与糖感知和激素反应途径的相互作用。
