The quantitative effects of different light sources on the growth parameters of pepper seedlings

In this research, the effects that three different light sources: a high pressure sodium lamp (HPS), an incandescent lamp (IL), a light emitting diode (LED) and two different colors (red and blue), have on the pepper seedling quality were determined in detail. The effects of light sources and colors on growth and quantitative characteristics of pepper seedlings were analyzed including the following: height of seedling, diameter of seedling, dry weights for root, stem and leaves, leaf weight ratio, stem weight ratio, root weight ratio, leaf area, leaf thickness, leaf area ratio and specific leaf area. According to the results obtained, it was seen that the effect of light sources and their colors on the growth and quantitative characteristics of pepper seedlings were different depending on the growing periods of autumn and spring. Light source treatments increased some characteristics, such as stem diameter and stem weight ratio. Under blue LED light conditions, the seedlings root, stem and leaf dry weights were much better compared to seedlings treated with other light sources. It has been determined that blue light sources, in particular, are more effective on the leaf area ratio in the autumn period. Blue LED lamps increased the leaf area in both periods, while the lowest leaf area value was found under the blue color of an IL light source in both periods. This study showed that pepper seedling growth is light limited during the spring period, and artificial LED lighting can significantly increase plant growth.