Nitrogen isotope composition in plant leaves and response to changes of growing temperature

摘要

Plant nitrogen isotope composition (δ15N) in a controlled field environment reveals details of relationship between plants and environmental factors. In order to determine the relationship between δ15N of winter wheat, Triticum aestivum and growing temperature, we analyzed leaf δ15N of winter wheat in an experimental field. Results showed that, under water-controlled conditions but varying temperatures changes through wheat growth periods in the Chinese Loess Plateau, δ15N values of wheat leaf from −8.1‰ to −1.6‰ are positively correlated with temperatures ranged from −2.2°C to 21.7°C, which could be attributed to the shift of δ15N of soil source and wheat physiological change by the temperature variation. Leaf δ15N variations provided useful proxies for seasonal plant nitrogen cycles, but a huge difference of δ15N in wheat lifecycle imply that different sampling date can influence us to accuracy interpret why reasons of plant δ15N changes. More study work of plant isotopic composition (C, N, S, etc.) research in plant lifetime should be done, which can give us more accurate information about plant isotopic composition changes because of environmental factors.