Final published version
Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Retrospective analysis of biochemical limitations to photosynthesis in 49 species
T2 - C4 crops appear still adapted to pre-industrial atmospheric [CO2]
AU - Pignon, C.P.
AU - Long, S.P.
PY - 2020/11/30
Y1 - 2020/11/30
N2 - 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.
AB - 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.
KW - A/ci curve
KW - C4 photosynthesis
KW - C4 subtype
KW - elevated CO2
KW - pre-industrial CO2
KW - stomatal conductance
KW - Vmax
KW - Vpmax
KW - water-use efficiency
U2 - 10.1111/pce.13863
DO - 10.1111/pce.13863
M3 - Journal article
VL - 43
SP - 2606
EP - 2622
JO - Plant, Cell and Environment
JF - Plant, Cell and Environment
SN - 0140-7791
IS - 11
ER -