Response of Growth and Development of Young Tomato Plants to End-of-day Monochromatic Light from Various LEDs

Abstract

Plant growth and development strongly influenced by light quantity and its spectralcomposition. Young tomato plants were cultivated in growth cabinets under artificial lightprovided by red and blue light emitting diodes(LEDs) during 12 hours, then plants wereexposed to monochromatic ultraviolet, blue, green and red lights as an end-of-day(EOD)treatment during 4 hours to study their effect on plant growth parameters. EOD lighting fromvarious LEDs increased total fresh and dry weights as well as assimilation area compared tothose in control. Blue light increased stem height, internode length and stem diameter. Monochromatic UV-A light reduced stem elongation, highly increased stomatal conductance. Compactness and health index of young tomato plants were increased in UV-A and red lighttreatments.