Abstract
We investigated the effects of the dissolved oxygen (DO) concentration in irrigation water on the growth and postproduction quality of potted cyclamen (Cyclamen persicum Mill.), grown using a recirculating Ebb & Flow subirrigation system (Ebb & Flow system). Four levels of DO were set: 4∼6 ppm (control, no air supply), 7∼9 ppm, 15∼18 ppm, and 30∼35 ppm, using an air compressor and two types of oxygen generator. The increase in the DO concentration of irrigation water caused a rise in the pH, but no alkalization of substrates or physiological damage of potted cyclamen was observed during cultivation. The results indicated that growth suppression during a high-temperature period was avoided by treatment with over 15 ppm DO; therefore, the growth and start of flowering of cyclamen were accelerated during the total cultivation period. Moreover, the results showed that the postproduction quality of cyclamen under floral display conditions at a low-light intensity was degraded easily over 15 ppm DO, but it was maintained for longer with 7∼9 ppm DO. From the above results, when the DO concentration in irrigation water was fixed until shipment, we considered that treatment with 7∼9 ppm DO, which facilitated a higher postproduction quality, was more desirable for potted cyclamen production with the Ebb & Flow system.
