Biochemical characteristics, yield and quality of ‘Jumilia’ rose grown under different light sources in the greenhouse condition

Rose is one of the most well-known ornamental cut flowers all over the world and high quality cut roses production in greenhouses is very important. Rose flower is a light-loving plant among ornamental flowers, and providing adequate light during the cultivation period is one of the important measures in increasing the yield and quality of greenhouse roses, in low light and cloudy days. Increasing the light available to roses in greenhouse cultivation is done by using supplementary light sources. During the last few years, the use of new supplementary lights as an alternative to old light sources in improving the growth and development conditions of ornamental plants has received much attention. For this purpose, the present study was conducted with the aim of investigating the effect of supplementary light source on the morphological and physiological indicators of ‘Jumilia’ rose. New supplementary lights, including combined light emitting diode (LED), were compared to conventional and old light sources such as metal halide (MH) and high-pressure sodium (HPS) to determine the optimal supplementary light source for the production of ‘Jumilia’ cut roses by hydroponic method, and natural sunlight during the cold season was used as control.

This experiment was conducted in the form of a completely randomized design with four light treatment groups including metal vapor supplementary lights, sodium high pressure, combined light emitting diodes and control (natural sunlight without supplementary exposure) in three replications and each replication includes four plants. The experiment was carried out in the specialized rose greenhouse located in the research greenhouse of the Faculty of Agriculture of Isfahan University of Technology in 1399-1400. In this research, morphological and physiological traits including bud length, flower stem diameter, calyx diameter, number of leaves at the time of flowering, number of flowers, amount of leaf chlorophylls a and b, relative leaf water content, leaf protein and leaf chlorophyll fluorescence of ‘Jumilia’ rose was measured.

Based on the obtained results, the effect of supplementary light treatments on the morphogenesis, morphological and physiological traits of ‘Jumilia’ cut roses were significant. Compared to the control treatment, the treatment of combined light diodes had the greatest effect on the indicators of bud length, diameter of flower stalk and diameter of calyx; A similar result was obtained in increasing the number of leaves and the number of flower branches. Also, the accumulation of leaf photosynthetic pigments, including chlorophylls, showed the greatest increase in light treatment with combined diodes. Growth light diodes were able to increase the relative water content of leaves significantly compared to other treatments. The amount of protein measured in rose leaf tissue treated with combined light diodes was higher than other treatments. By examining the chlorophyll fluorescence index, it was found that light diodes provided more suitable growing conditions for the growth of rose bushes. Among the investigated treatments, the highest quantity and quality of ‘Jumilia’ cut roses were created by combined light emitting diode treatments compared to other supplementary light treatments as well as the control treatment.

Considering the favorable effects of combined light diode treatments on the quantitative and qualitative characteristics of ‘Jumilia’ rose and considering the higher energy efficiency and economic efficiency in a longer period of time in greenhouse cultivation, the use of combined light diodes in lighting supplementation of intensive crops is a priority. Combined diode supplementary lights are recommended due to their significant superiority over the control and their positive role in improving the growth and development of ‘Jumilia’ roses; Also, the complementary light of combined diodes is recommended as an alternative to metal vapor and high pressure sodium.