EFFECTS OF CO2 CONCENTRATION ON STRAWBERRY - III - DRY-MATTER PRODUCTION AND WATER-CONSUMPTION

Two-week-old strawberry (Fragaria x ananassa Duch. cv. 'Elsanta') plan ts were acclimatized to 300, 450, 600, 750 or 900 ppm CO2 in controlle d environment chambers for 50 days. Elevated CO2 concentrations enhanc ed dry matter production, the root/shoot ratio and total water consump tion of the plants. High CO2 promoted total dry matter increment and t otal leaf area increment of the plants, and improved dry matter-produc tion efficiency and plant water-use efficiency. Water-consumption rate of plants and water-uptake efficiency of roots, however, declined at CO2-enriched conditions. In comparison with the 300 ppm CO2 treatment, 600 and 900 ppm CO2-grown plants increased dry matter-production effi ciency by 37 % and 67 %, water-use efficiency by 137 % and 272 %, whil e reduced water-consumption rate by 39 % and 55 %, and water-uptake ef ficiency of roots by 53 % and 76 %, respectively. Increasing CO2 conce ntrations from 300 to 900 ppm enabled strawberry plants to produce dry matter more efficiently and to use soil water more economically becau se it reduced the impact of water stress on plant productivity.