CO₂ diffusion in tobacco: a link between mesophyll conductance and leaf anatomy.

ABSTRACT: The partial pressure of CO₂ at the sites of carboxylation within chloroplasts depends on the conductance to CO₂ diffusion from intercellular airspace to the sites of carboxylation, termed mesophyll conductance (g _m). We investigated how g _m varies with leaf age and through a tobacco (Nicotiana tabacum) canopy by combining gas exchange and carbon isotope measurements using tunable diode laser spectroscopy. We combined these measurements with the anatomical characterization of leaves. CO₂ assimilation rate, A, and g _m decreased as leaves aged and moved lower in the canopy and were linearly correlated. This was accompanied by large anatomical changes including an increase in leaf thickness. Ch

SUBMITTER: Clarke VC 

PROVIDER: S-EPMC7898150 | biostudies-literature | 2021 Apr

REPOSITORIES: biostudies-literature