Measurement of leaf day respiration using a new isotopic disequilibrium method compared with the Laisk method

摘要: Quantification of leaf respiration is great importance for the understanding plant physiology and ecosystem biogeochemical processes. Leaf continues in light (RL) but supposedly at a lower rate compared to dark (RD). Yet, there no method direct measurement RL most available methods require unphysiological conditions. A based on isotopic disequilibrium quantified (RL 13C) mesophyll conductance young old fully-expanded leaves six species 13C values determined by Laisk Laisk). RL were consistently than RD. ageing negatively affected photosynthetic performance, had significant effect or RL/RD as both methods. measured successively same correlated positively (r2=0.38), average was 28% 13C. Using A/Cc curves instead A/Ci curves, higher photocompensation point Γ* (by 5 μmol mol-1) found correction influence estimates. The results suggest that underestimated RL. The useful assessing responses irradiance CO2, improving our mechanistic