Genotypic variation in source and sink traits affects the response of photosynthesis and growth to elevated atmospheric CO2.

Denis Fabre, Michael Dingkuhn, Xinyou Yin, Anne Clément-Vidal, Sandrine Roques, Armelle Soutiras, Delphine Luquet

Plant, cell & environment 2020 Mar

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This study aimed to understand the response of photosynthesis and growth to e-CO2 conditions (800 vs. 400 μmol mol-1 ) of rice genotypes differing in source-sink relationships. A proxy trait called local C source-sink ratio was defined as the ratio of flag leaf area to the number of spikelets on the corresponding panicle, and five genotypes differing in this ratio were grown in a controlled greenhouse. Differential CO2 resources were applied either during the 2 weeks following heading (EXP1) or during the whole growth cycle (EXP2). Under e-CO2 , low source-sink ratio cultivars (LSS) had greater gains in photosynthesis, and they accumulated less nonstructural carbohydrate in the flag leaf than high source-sink ratio cultivars (HSS). In EXP2, grain yield and biomass gain was also greater in LSS probably caused by their strong sink. Photosynthetic capacity response to e-CO2 was negatively correlated across genotypes with local C source-sink ratio, a trait highly conserved across environments. HSS were sink-limited under e-CO2 , probably associated with low triose phosphate utilization (TPU) capacity. We suggest that the local C source-sink ratio is a potential target for selecting more CO2 -responsive cultivars, pending validation for a broader genotypic spectrum and for field conditions. © 2019 John Wiley & Sons Ltd.

Citation

Denis Fabre, Michael Dingkuhn, Xinyou Yin, Anne Clément-Vidal, Sandrine Roques, Armelle Soutiras, Delphine Luquet. Genotypic variation in source and sink traits affects the response of photosynthesis and growth to elevated atmospheric CO2. Plant, cell & environment. 2020 Mar;43(3):579-593