2017 Volume 86 Issue 3 Pages 389-394
To increase the photosynthesis of crop and improve plant quality, we evaluated the effect of elevated CO2 on vegetative growth and flowering in Phalaenopsis ‘Fuller’s Pink Swallow’. Plants were exposed to 450 (control), 800, 1600, and 2400 μmol·mol−1 CO2 for 31 weeks. The number of leaves, leaf length, and leaf width displayed greater increases in plants grown under 1600 and 2400 μmol·mol−1 CO2 than in plants grown under 450 and 800 μmol·mol−1 CO2. The times to leaf initiation were reduced to 90.7 and 85.8 days in plants grown under 1600 and 2400 μmol·mol−1 CO2, respectively, compared with that of the control, 177.1 days. The leaf elongation rate was significantly increased in plants grown under 1600 and 2400 μmol·mol−1 CO2 compared to plants grown under 450 and 800 μmol·mol−1 CO2. Plants grown under 1600 μmol·mol−1 CO2 had the highest total number of flower buds among all plants grown under the four tested CO2 concentrations. Leaf injuries were not observed in any plants regardless of CO2 concentration, but flower bud abortion and bud withering were observed in CO2-enriched plants, especially in plants grown under 1600 and 2400 μmol·mol−1 CO2. Plants subjected to long-term CO2 elevation of over 800 μmol·mol−1 displayed increased biomass production despite a concomitant reduction in the number of buds. These results showed that 1600 and 2400 μmol·mol−1 CO2 significantly enhanced the vegetative growth of Phalaenopsis. However, long-term exposure to high CO2 concentrations can adversely affect the flowering of Phalaenopsis, and result in reduced flower production and increased flower bud abortion.