Retrospective analysis of biochemical limitations to photosynthesis in 49 species:C4 crops appear still adapted to pre-industrial atmospheric [CO2]

Pignon, C.P. and Long, S.P. (2020) Retrospective analysis of biochemical limitations to photosynthesis in 49 species:C4 crops appear still adapted to pre-industrial atmospheric [CO2]. Plant, Cell and Environment, 43 (11). pp. 2606-2622. ISSN 0140-7791

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Abstract

Leaf CO2 uptake (A) in C4 photosynthesis is limited by the maximum apparent rate of PEPc carboxylation (Vpmax) at low intercellular [CO2] (ci) with a sharp transition to a ci-saturated rate (Vmax) due to co-limitation by ribulose-1:5-bisphosphate carboxylase/oxygenase (Rubisco) and regeneration of PEP. The response of A to ci has been widely used to determine these two parameters. Vmax and Vpmax depend on different enzymes but draw on a shared pool of leaf resources, such that resource distribution is optimized, and A maximized, when Vmax and Vpmax are co-limiting. We collected published A/ci curves in 49 C4 species and assessed variation in photosynthetic traits between phylogenetic groups, and as a function of atmospheric [CO2]. The balance of Vmax-Vpmax varied among evolutionary lineages and C4 subtypes. Operating A was strongly Vmax-limited, such that re-allocation of resources from Vpmax towards Vmax was predicted to improve A by 12% in C4 crops. This would not require additional inputs but rather altered partitioning of existing leaf nutrients, resulting in increased water and nutrient-use efficiency. Optimal partitioning was achieved only in plants grown at pre-industrial atmospheric [CO2], suggesting C4 crops have not adjusted to the rapid increase in atmospheric [CO2] of the past few decades.

Item Type:
Journal Article
Journal or Publication Title:
Plant, Cell and Environment
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/1300/1314
Subjects:
ID Code:
156124
Deposited By:
Deposited On:
14 Jun 2021 14:40
Refereed?:
Yes
Published?:
Published
Last Modified:
20 Oct 2021 05:50