The Effect of Various Wavelengths of LED Light on the Physiological and Morphological Parameters of Comfrey (Symphytum officinale L.)

Abstract

The aim of this study was to examine the effect of five different wavelengths of light on the comfrey plant (Symphytum officinale) (family Boraginaceae). The light source and wavelengths used in the study were UV-A (390-410 nm), blue (465-485 nm), red (620-630 nm) and cool white (CW) daylight (400-700 nm, 6500 K), LED (Light Emitting Diode). In the study, each of the 5 different light applications was applied for 45 days (T1: 100% blue; T2: 100% red; T3: 60% blue + 35% red + 5% UV-A; T4: 100% CW daylight; T5: 80% CW + 20% red). The experiments were carried out under conditions of 22C temperature, 60% humidity, 16/8 hours light/dark and 180 µmol.m-2.s-1 Photosynthetically Active Radiation (PAR). After each application, measurements were taken of number of leaves, number of roots, height of plant, amount of chlorophyll in leaves, leaf colour and brightness. According to data obtained, the different wavelengths of the coloured light applied in the growing environment created a change in colour and brightness of the leaves, height of the plant, length of the roots, and number of leaves and roots.