Effect of EOD-FR on the Growth and Morphology of Brassicaceae Family Plants in Each Cropping Season

Abstract

The effect of irradiation with far-red (FR) light at the end of the day (EOD) on the yield and trait of plants in the family Brassicaceae was investigated. When plants were exposed to FR light under weak irradiation (34.33 or 13.44 mW・m^–2) by EOD treatment, the total leaf weight and leaf area tended to increase more than in plants without treatment and under strong irradiation (96.04 or 56.70 mW・m^–2). They were cultivated in winter, midsummer, and the period between winter and midsummer in Okinawa, with a sub-tropical climate, and then compared regarding the difference in each growth between the cultivated periods. In shimana, EOD-FR treatment promoted bolting. It was significantly promoted under strong irradiation compared with weak irradiation. However, there was no bolting except in shimana. Also, in shimana and bok choy receiving strong irradiation and EOD-FR treatment, stem elongation was promoted by more than 8 times and 2 times, respectively, on comparison with plants without treatment.