Evans R D
University of Arkansas Stable Isotope Laboratory, Biological Sciences, University of Arkansas, Fayetteville, AR 72701, USA.
Trends Plant Sci. 2001 Mar;6(3):121-6. doi: 10.1016/s1360-1385(01)01889-1.
Whole-plant and leaf nitrogen isotope composition are determined by the isotope ratio of the external nitrogen source and physiological mechanisms within the plant. Whole-plant isotope composition can reflect that of the nitrogen source when plant demand exceeds nitrogen supply. Uptake by mycorrhizae can cause the isotope ratio of the plant to deviate from the source. Intra-plant variation in isotope composition can be caused by multiple assimilation events, organ-specific loss of nitrogen, and resorption and reallocation of nitrogen. Future work must address acquisition of organic nitrogen from the soil solution, the role of mycorrhizae, and internal transformations within the plant.
整株植物和叶片的氮同位素组成由外部氮源的同位素比率和植物体内的生理机制决定。当植物需求超过氮供应时，整株植物的同位素组成可以反映氮源的同位素组成。菌根的吸收会导致植物的同位素比率偏离氮源。植物体内同位素组成的变化可能由多种同化事件、器官特异性的氮损失以及氮的再吸收和重新分配引起。未来的工作必须解决从土壤溶液中获取有机氮、菌根的作用以及植物体内的内部转化等问题。
