Association between Carbonyl Sulfide Uptake and 18Δ during Gas Exchange in C3 and C4 Leaves
| Autor: | Steve A. Montzka, Joseph A. Berry, Keren Stimler, Dan Yakir |
|---|---|
| Rok vydání: | 2011 |
| Předmět: |
Stomatal conductance
biology Physiology Sulfur Oxides Water Conductance Plant Science Plant Leaves chemistry.chemical_compound Biochemistry chemistry Carbonic anhydrase Genetics biology.protein Biophysics Salvia Linear correlation Phosphoenolpyruvate carboxylase Co2 exchange Whole Plant and Ecophysiology Carbonyl sulfide |
| Zdroj: | Plant Physiology. 157:509-517 |
| ISSN: | 1532-2548 0032-0889 |
| DOI: | 10.1104/pp.111.176578 |
| Popis: | Carbonyl sulfide (COS) and C(18)OO exchange by leaves provide potentially powerful tracers of biosphere-atmosphere CO(2) exchange, and both are assumed to depend on carbonic anhydrase (CA) activity and conductance along the diffusive pathway in leaves. We investigated these links using C(3) and C(4) plants, hypothesizing that the rates of COS and C(18)OO exchange by leaves respond in parallel to environmental and biological drivers. Using CA-deficient antisense lines of C(4) and C(3) plants, COS uptake was essentially eliminated and discrimination against C(18)OO exchange ((18)Δ) greatly reduced, demonstrating CA's key role in both processes. (18)Δ showed a positive linear correlation with leaf relative uptake (LRU; ratio of COS to CO(2) assimilation rates, A(s)/A(c), normalized to their respective ambient concentrations), which reflected the effects of stomatal conductance on both COS and C(18)OO exchange. Unexpectedly, a decoupling between A(s) and (18)Δ was observed in comparing C(4) and C(3) plants, with a large decrease in (18)Δ but no parallel reduction in A(s) in the former. This could be explained by C(4) plants having higher COS concentrations at the CA site (maintaining high A(s) with reduced CA) and a high phosphoenolpyruvate carboxylase/CA activity ratio (reducing (18)O exchange efficiency between CO(2) and water, but not A(s)). Similar A(s) but higher A(c) in C(4) versus C(3) plants resulted in lower LRU values in the former (1.16 ± 0.20 and 1.82 ± 0.18 for C(4) and C(3), respectively). LRU was, however, relatively constant in both plant types across a wide range of conditions, except low light (191 μmol photon m(-2) s(-1)). |
| Databáze: | OpenAIRE |
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