Abstract
Seedlings of sunflower, tomato and lettuce were cultivated under blue-, red- monochromatic LED lights and white light by fluorescent lamp. Stem elongation of sunflower was promoted by blue light, and those of tomato and lettuce were promoted by red light. Length and number of epidermal cells in each plant were increased under the respective promotive light in stem elongation. Main factor of 1st internode growth was cell division in sunflower under blue light and tomato under red light, but that of 3rd internode growth was cell elongation. In lettuce under red light, each of the factors for 1st and 3rd internode elongation was cell growth and cell division, respectively. Thus, different stem elongation under different light quality was controlled by both of cell growth and cell division. However, the change in cell growth and cell division was different, according to plant species and stem position.
