Atkin, Owen K., Turnbull, Matthew H., Zaragoza-Castells, Joana, Fyllas, Nikolaos M., Lloyd, Jon, Meir, Patrick, and Griffin, Kevin L. (2013) Light inhibition of leaf respiration as soil fertility declines along a post-glacial chronosequence in New Zealand: an analysis using the Kok method. Plant and Soil, 367 (1-2). pp. 163-182.

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Abstract

Background and aims: Our study quantified variations leaf respiration in darkness (RD) and light (RL), and associated traits along the Franz Josef Glacier soil development chronosequence in New Zealand.

Methods: At six sites along the chronosequence (soil age: 6, 60, 150, 500, 12,000 and 120,000 years old), we measured rates of leaf RD, RL (using Kok method), light-saturated CO2 assimilation rates (A), leaf mass per unit area (MA), and concentrations of leaf nitrogen ([N]), phosphorus ([P]), soluble sugars and starch.

Results: The chronosequence was characterised by decreasing RD, RL and A, reduced [N] and [P] and increasing MA as soil age increased. Light inhibition of R occurred across the chronosequence (mean inhibition = 16 %), resulting in ratios of RL:A being lower than for RD:A. Importantly, the degree of light inhibition differed across the chronosequence, being lowest at young sites and highest at old sites. This resulted in RL:A ratios being relatively constant across the chronosequence, whereas RD:A ratios increased with increasing soil age. Log-log R-A-MA-[N] relationships remained constant along the chronosequence. By contrast, relationships linking rates of leaf R to [P] differed among leaves with low vs high [N]:[P] ratios. Slopes of log-log bivariate relationships linking RL to A, MA, [N] and [P] were steeper than that for RD.

Conclusions: Our findings have important implications for predictive models that seek to account for light inhibition of R, and for our understanding of how environmental gradients impact on leaf trait relationships.

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