A meta-analysis of leaf nitrogen distribution within plant canopies

著者

Hikosaka K., Anten N. P. R., Borjigidai A., Kamiyama C., Sakai H., Hasegawa T., Oikawa S., Iio A., Watanabe M., Koike T., Nishina K., Ito A.

雑誌名

Annals of Botany 118, 239–247

DOI

10.1093/aob/mcw099

概要

Background and aims Leaf nitrogen distribution in the plant canopy is an important determinant for canopy photosynthesis. Although leaf nitrogen distribution is known to be driven mainly by light distribution, its quantitative variations among species and environmental responses remain unknown. Here, we conducted a global meta-analysis of leaf nitrogen distribution in plant canopies.

Methods We collected data of the nitrogen distribution and environmental variables from 393 plant canopies.

Key results The trends were clearly different between wheat and other species; the photosynthetic nitrogen distribution coefficient (K_b) was mainly determined by LAI in wheat, whereas it was correlated with light extinction coefficient (K_L) and LAI in other species. Some of other variables were found to influence the value of K_b. We present the best model for K_b as a function of environmental variables. As a more simple function, K_b = 0.48K_L can be used for canopies of species other than wheat. Sensitivity analyses using a terrestrial carbon flux model showed that gross primary production tended to be more sensitive to the K_b value especially when nitrogen content of the uppermost leaf is fixed.

Conclusion The nitrogen distribution is influenced by various factors and the vertical light gradient is a main driver of nitrogen distribution in the canopy in most species. Our models contribute to an improvement in the projection of plant productivity and cycling of carbon and nitrogen in terrestrial ecosystems.