Rowland, L. ; Zaragoza-Castells ; Bloomfield, K. J. ; Turnbull, M. H. ; Bonal, D. ; Burban, B. ; Salinas, N. ; Cosio, E. ; Metcalfe, D. J. ; Ford ; Phillips, O. L. ; Atkin, O. K. ; Meir, P.
New Phytologist, 2017, 214 (3) : 1064-1077.
Article
Leaf dark respiration (R-dark) represents an important component controlling the carbon balance in tropical forests. Here, we test how nitrogen (N) and phosphorus (P) affect R-dark and its relationship with photosynthesis using three widely separated tropical forests which differ in soil fertility. R-dark was measured on 431 rainforest canopy trees, from 182 species, in French Guiana, Peru and Australia. The variation in R-dark was examined in relation to leaf N and P content, leaf structure and maximum photosynthetic rates at ambient and saturating atmospheric CO2 concentration. We found that the site with the lowest fertility (French Guiana) exhibited greater rates of R-dark per unit leaf N, P and photosynthesis. The data from Australia, for which there were no phylogenetic overlaps with the samples from the South American sites, yielded the most distinct relationships of R-dark with the measured leaf traits. Our data indicate that no single universal scaling relationship accounts for variation in R-dark across this large biogeographical space. Variability between sites in the absolute rates of R-dark and the R-dark : photosynthesis ratio were driven by variations in N- and P-use efficiency, which were related to both taxonomic and environmental variability.