Effects of elevated CO_2 on plant growth and nutrient partitioning of rice (Oryza sativa L.) at rapid tillering and physiological maturity

摘要

This work investigates the relationship between plant growth, grain yield, nutrient acquisition and partitioning in rice (Oryza sativa L.) under elevated CO_2. Plants were grown hydroponically in growth chambers with a 12-h photoperiod at either 370 or 700 mmol CO_2 mol~(-1) concentration. Plant dry mass (DM), grain yield and macroand micronutrient concentrations of vegetative organs and grains were determined. Elevated CO_2 increased biomass at tillering, and this was largely due to an increase in root mass by 160%. Elevated CO_2 had no effect on total nutrient uptake (N, P, K, Mg and Ca). However, nutrient partitioning among organs was significantly altered. N partitioning to leaf blades was significantly decreased, whereas the N partitioning into the leaf sheaths and roots was increased. Nutrient use efficiency of N, P, K, and Mg in all organs was significantly increased at elevated CO_2. At harvest maturity, grain yield was increased by 27% at elevated CO_2 while grain (protein) concentration was decreased by a similar magnitude (28%), suggesting that critical nutrient requirements for rice might need to be reassessed with global climate change.