The Utilization and Roles of Nitrogen in Plants

Abstract

Nitrogen (N) is an essential mineral element for plants and is the main component of protein, nucleic acid, phospholipid, chlorophyll, hormones, vitamins and alkaloids. It is involved in all stages of plant growth and development. Low-N stress seriously hinders plant growth and reduces yield and quality. Plants have evolved a series of elaborate regulatory mechanisms for N uptake and assimilation to cope with different soil N states. After N is absorbed and utilized by plants, it plays important regulatory roles in phytohormones, microRNA (miRNA), root development and mycorrhizal symbiosis to cope with environmental stress. Here, we highlight the research progress on the regulation mechanisms for N absorption and assimilation. Then, we emphasize the regulation roles of N regarding hormone signals, miRNA, lateral root growth, drought resistance, anthocyanin synthesis and mycorrhizal symbiosis. A thorough understanding of N uptake, utilization and interaction with other biological processes is helpful to improve N use efficiency and to breed plants with “less-input-more-output”.