Effect of micro bubble water on the growth and morphology of three leaf lettuce cultivars (Lactuca sativa L.) grown under two kinds of LED irradiation

Abstract

ABSTRACT This study examined the effects of micro-bubble water and two types of light-emitting diode (LED) irradiation (blue and red-blue) on the growth and morphology of three lettuce cultivars (Lactuca sativa L.). The growth in the above-ground portions of the two cultivars was reduced by the use of micro-bubble water depending on the type of LED irradiation employed. In particular the leaf weight of ‘Fancy green’ cultivated for 21 days under red-blue LED was significantly lower when it was grown with air-pumped micro-bubble water. The leaf weight of ‘Fancy red’ cultivated under blue LED and ‘Red fire’ under red-blue LED irradiation was significantly greater when they were grown with micro-bubble water than when they were grown without micro-bubble water. These results show that the effect of micro-bubble water differed between the cultivars and the types of LED irradiation employed. Furthermore, the use of an air pump is recommended when the generation of micro-bubbles in water is very intermittent, as in this experiment.