Rose with the scientific name L. Rosa hybida is one of the most important and popular ornamental cut flowers in the world. Therefore, producing and buying roses in a shorter time and with better quality is of great commercial importance. In buying roses One of the important measures in increasing the yield and quality of greenhouse roses is increasing the light available to the plant in cloudy and low-light weather conditions, which has a great impact on buying roses. Nowadays, the use of new supplementary light sources as a replacement for old light sources in buying roses and also improving the growth and development conditions of ornamental plants such as roses is of interest, and in some cases, better and more effective effects of these light sources than old light sources have been observed. This study aimed to investigate the effectiveness of new hybrid diode light sources in comparison with conventional and old metal halide and high-pressure sodium light sources on morphological and physiological indicators of the Samurai rose cultivar. The effect of natural light in the cold season as a control on this plant was also investigated. Therefore, in order to determine the optimal supplemental light source for hydroponic production of cut roses of the Samurai variety, supplemental lighting with metal halide lamps, high-pressure sodium lamps, and light-emitting diodes was used to grow greenhouse roses of the Samurai variety.
Materials and Methods
This experiment was conducted in a completely randomized design with 4 treatment groups including metal halide supplemental lights, high-pressure sodium lamps, and combined light-emitting diodes compared to the control (natural sunlight) in 3 replications with 4 rose plants in each replication in the research greenhouse of the Faculty of Agriculture, Isfahan University of Technology and the Horticulture Laboratory in 2018-2019. Morphological and biochemical traits including stem length, bud diameter, fresh and dry weight of flower stem, chlorophyll and carotenoid content, carbohydrate and anthocyanin content, purity quality of cut rose flowers of Samurai cultivar were measured in this experiment.
Findings
Based on the results obtained, supplementary light treatments had a significant effect on morphological and physiological traits of Samurai cultivar roses at the 1% level. Compared to the control treatment, the mixed light diode treatment had the greatest effect on morphological indices of bud and flower stem diameter; similar results were obtained in increasing fresh and dry weight of the plant; also, the accumulation of photosynthetic pigments was the highest in the combined light diode treatment. LED growth lights were able to significantly increase the level of soluble carbohydrates and anthocyanin content compared to other treatments. By examining the flower quality index, it was determined that LED lights improved the flower appearance characteristics and the highest flower yield was in the combined LED light treatment. Among the treatments studied, the best and highest quantity and quality of cut rose flowers were observed with the combined LED treatments compared to other supplementary light treatments and the control treatment.
Conclusion
Given the favorable effects of combined LED treatments on the quality characteristics and yield of Samurai rose cultivars, considering higher energy efficiency, longer life, and economic savings over a longer period of time in greenhouse cultivation, the use of combined LED lights in supplementary lighting of intensive cultivation is a priority. Hybrid diode supplemental lights are also recommended due to their significant superiority over the control and the positive role they play in improving the growth and development of the Samurai rose variety; hybrid diode supplemental light is also recommended as an alternative to metal halide and high-pressure sodium supplemental lights.
Comments