Single and interactive effects of temperature, carbon dioxide and watering regime on plant growth and reproductive yield of two genotypes of Arabidopsis thaliana

Interactive effects of temperature, carbon dioxide (CO₂), and watering regime on the reproductive yield of plants have not yet been fully understood. We grew Arabidopsis thaliana (wild-type (WT) and abi1-1, ABA-insensitive mutant) plants under two temperature regimes (22/18 °C and 28/24 °C; 16 h light/8 h dark), two CO₂ concentrations (400 and 700 μmol mol^–1), and two watering regimes (well-watered and water-stressed) for 34 days, and measured plant growth, reproductive yield and seed free amino acids. Plant growth and yield were decreased by higher temperatures and water stress, but aborted seed number was increased by water stress. Stem height and aborted seed number were decreased, but silique width and mass were increased, by elevated CO₂. Stem diameter, and silique width and mass were lowest in the water-stressed abi1-1 plants grown under higher temperatures at elevated CO₂. Under higher temperatures, elevated CO₂ and water stress, the abi1-1 plants produced seeds with lower amino acids than the WT plants. Most amino acids were increased by higher temperatures and elevated CO₂ than by water stress. Elevated CO₂ partially mitigated the adverse effects of stresses on some traits in both genotypes, with a larger extent in the WT plants than in the abi1-1 plants, and indirectly indicating the role of endogenous ABA in the process.