关键词: 城市生态用地, 功能型生态用地, 服务型生态用地, 生态系统服务

Abstract: Nitrogen is a necessary nutritional element, and also, a main limiting factor in plant growth. The nitrogen source and its uptake by plants in terrestrial ecosystems are controlled by their types and habitats. The change of environments can change the plant nitrogen supply through changing the nitrogen form, concentration and distribution, and may lead to the change of soil quality, water regime, and illumination condition. These changes often bring coupling phenomena, and affect plant physiological and ecological characteristics, which subsequently affect the nitrogen uptake and utilization by plants. Moreover, these changes also lead to the variations of plant populations and biological diversity, and hence, directly affect the function and evolution of ecosystem. This paper mainly summarized the nitrogen sources in higher plants growing in terrestrial ecosystems, and analyzed the affecting factors during their nitrogen uptake and utilization. The prospect in this research field was discussed.

Key words: Urban ecological land, Ecological land for functioning, Ecological land for service, Ecosystem service