Investigation of the effect of different light sources on some physiological and morphological characteristics of samurai rose

Rose with the scientific name of L. Rosa hybida is one of the most important and popular ornamental flowers in the world. Therefore, its production in less time and with better quality is of great commercial importance. One of the important measures in increasing the yield and quality of greenhouse roses is to increase the light available to the plant in cloudy and low light climates. For this purpose, supplementary light is used in the period of plant cultivation. Today, the use of new complementary light sources as an alternative to old light sources in improving the growth conditions of ornamental plants is considered, and in some cases, better and more effective effects of these light sources than old light sources have been observed. The aim of this study was to investigate the effect of light source of composite and new diodes in comparison with conventional and old metal halide and high pressure sodium light sources on morphological and physiological indices of Samurai rose. The effect of natural light in the cold season in this plant was also investigated as control. Therefore, in order to determine the optimal complementary light source for the production of cut branches of samurai cultivar by hydroponic method, supplemental exposure with metal vapor, high pressure sodium lamps, and growth light emitting diodes were used to grow greenhouse roses of Samurai cultivar.

This experiment was conducted in a completely randomized design with 4 treatment groups including complementary metal halide lights, high pressure sodium and combined light emitting diodes were compared to the control (natural sunlight) in 3 replications with 4 rose bushes per replication. It was conducted in the research greenhouse of the Faculty of Agriculture of Isfahan University of Technology and the Horticulture Laboratory in 1400-1399hsh. Morphological and biochemical traits including stem length, bud diameter, fresh and dry weight of flower stem, chlorophyll and carotenoid content, carbohydrate and anthocyanin content, pure quality of cut flower yield of Samurai rose were measured in this experiment.

Based on the results, supplementary light treatments had a significant effect on the morphological and physiological traits of Samurai rose at 1% level. Compared to the control treatment, the treatment of mixed light emitting diodes had the greatest effect on the morphological indices of bud and stem diameter; A similar result was obtained in wet and dry weight gain of the plant; Accumulation of photosynthetic pigments also had the highest level in light treatment of composite diodes. Growth light emitting diodes were able to significantly increase the level of soluble carbohydrates and anthocyanin content compared to other treatments. Examining the flower quality index, it was found that light emitting diodes improved the appearance characteristics of the flower and the highest flower performance was in the light treatment of the combined diode. Among the studied treatments, the best and highest quantity and quality of cut roses were observed by the treatments of combined light emitting diodes in comparison with other complementary light treatments as well as the control treatment.

Considering the favorable effects of combined light emitting diode treatments on the quality characteristics and yield of Samurai rose, considering higher energy efficiency, longer life and longer economic time in greenhouse crops, use Composite light emitting diodes are a priority in supplementary exposure of intensive cultures. Complementary diode supplementary lights are also recommended due to their significant superiority over the control and their positive role in improving the growth and development process of the samurai rose; Complementary diode light is also recommended as an alternative to high-pressure sodium and metal halide lights.