| Autor: |
Zhou H; School of Earth System Science, Institute of Surface-Earth System Science, Tianjin University, Tianjin, China.; School of the Environment, Yale University, New Haven, Connecticut, USA., Akçay E; Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania, USA., Helliker B; Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania, USA. |
| Jazyk: |
angličtina |
| Zdroj: |
Plant, cell & environment [Plant Cell Environ] 2023 Mar; Vol. 46 (3), pp. 796-811. Date of Electronic Publication: 2023 Jan 04. |
| DOI: |
10.1111/pce.14506 |
| Abstrakt: |
Each of >20 independent evolutions of C 4 photosynthesis in grasses required reorganization of the Calvin-Benson-cycle (CB-cycle) within the leaf, along with coordination of C 4 -cycle enzymes with the CB-cycle to maximize CO 2 assimilation. Considering the vast amount of time over which C 4 evolved, we hypothesized (i) trait divergences exist within and across lineages with both C 4 and closely related C 3 grasses, (ii) trends in traits after C 4 evolution yield the optimization of C 4 through time, and (iii) the presence/absence of trends in coordination between the CB-cycle and C 4 -cycle provides information on the strength of selection. To address these hypotheses, we used a combination of optimality modelling, physiological measurements and phylogenetic-comparative-analysis. Photosynthesis was optimized after the evolution of C 4 causing diversification in maximal assimilation, electron transport, Rubisco carboxylation, phosphoenolpyruvate carboxylase and chlorophyll within C 4 lineages. Both theory and measurements indicated a higher light-reaction to CB-cycle ratio (J atpmax /V cmax ) in C 4 than C 3 . There were no evolutionary trends with photosynthetic coordination between the CB-cycle, light reactions and the C 4 -cycle, suggesting strong initial selection for coordination. The coordination of CB-C 4 -cycles (V pmax /V cmax ) was optimal for CO 2 of 200 ppm, not to current conditions. Our model indicated that a higher than optimal V pmax /V cmax affects assimilation minimally, thus lessening recent selection to decrease V pmax /V cmax .
(© 2022 John Wiley & Sons Ltd.) |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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