Improving the postharvest quality characteristics of cut rose (Rosa×hybrida L.) ‘Red Alert’ in response to light intensity

Cut roses are one of the most important flowers in the ornamental plant industry that are widely cultivated all over the world. Longevity and postharvest quality is the most important characteristic in evaluating the quality of cut flowers which is influenced by various pre and post-harvest factors. Light, as one of the environmental cues in the postharvest condition of cut flowers, can play an important role in its qualitative characteristics. To the best of our knowledge, no detailed study has been reported so far in this case. This study aimed to investigate the intensity of light required for preserving the quality of cut flowers during the postharvest handling. This experiment was carried out as factorial in a completely randomized design with three replications in a postharvest room. The area was divided into three sections by optical shutters and the light intensity levels were applied in each section. Treatments were designed at three levels of light intensity of 15, 25 and 50 µmol m-2 s-1 emitting by LED lighting bulbs. The studied traits were vase life, activity of catalase and peroxidase enzymes, proline, relative fresh weight, anthocyanin, carotenoid and chlorophyll content. Results showed that the highest activity of catalase and peroxidase enzymes were at light intensity of 15 and 50 µmol m-2 s-1, respectively, and their activity decreased significantly during the vase life. The proline content increased with time and the highest level was observed in all three treatments on day 9 after harvest. The highest relative fresh weight was observed at light intensity of 15 µmol m-2 s-1 and in the vase life on the third day after harvest. The lowest relative fresh weight was also in the light intensity of 25 µmol m-2 s-1. In spite of these observations, however, there was no significant difference between the vase life, carotenoids, chlorophyll and anthocyanins of cut flowers at light intensities of 15, 25, and 50 µmol m-2 s-1. According to the results of this study, in order to improve the qualitative and quantitative characteristics of cut flowers during the post-harvest period, the light intensity of 15 µmol m-2 s-1 is recommended for flower shops industry.