Effect of Light Emitting Diode (LED) Light on Growth and Flowering of Pot-mum ‘Orange Egg’ during Cultivation

Abstract

This study was carried out to investigate the effect of the LED light source on the growth and flowering characteristics in potted chrysanthemum ‘Orange Egg’ during cultivation in a closed growth chamber with a constant temperature of 22℃ and a photoperiod consisted of 11 hours light and 13 hours darkness. Each LED light source of blue (444 nm), red (652 nm), or mixed LED (blue:red:white=2:5:1) was supplied separately. As a result, the plant height of the pot-mum 'Orange Egg' grown in red LED was longest with an average of 9.43 cm. And the plant height in blue LED was shorter than in mixed LED, but there was not statistically significant between them. The plant width and leaf width were also largest in plants grown under red LED similar to the growth response of the plant height. But the number of leaves and leaf lengths were more and longer in monochromatic LED such as blue or red than mixed LED. Flower bud differentiation was completed around 16 to 17 days after short-day treatment regardless of LED light source. However, pot-mum plants grown in red and blue LED did not develop flower buds normally and reach final flowering although those grown in mixed LED were fully flowered around 5 weeks after short-day treatment. Therefore, it is considered that the mixed LED consisting of blue, red and white is useful as LED light source for producing potted chrysanthemums in plant factories.