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Genotypic variation in source and sink traits affects the response of photosynthesis and growth to elevated atmospheric CO 2
Author(s) -
Fabre Denis,
Dingkuhn Michael,
Yin Xinyou,
ClémentVidal Anne,
Roques Sandrine,
Soutiras Armelle,
Luquet Delphine
Publication year - 2020
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/pce.13693
Subject(s) - sink (geography) , photosynthesis , cultivar , heat sink , agronomy , horticulture , chemistry , biology , botany , physics , cartography , geography , thermodynamics
This study aimed to understand the response of photosynthesis and growth to e‐CO 2 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 CO 2 resources were applied either during the 2 weeks following heading (EXP1) or during the whole growth cycle (EXP2). Under e‐CO 2 , 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‐CO 2 was negatively correlated across genotypes with local C source–sink ratio, a trait highly conserved across environments. HSS were sink‐limited under e‐CO 2 , 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 CO 2 ‐responsive cultivars, pending validation for a broader genotypic spectrum and for field conditions.