| Abstrakt: |
Greenhouse-grown roses are irradiance-dependent flowering plants needing more supplemental lighting for higher marketability and postharvest quality. To investigate physiological and biochemical responses of two varieties of Rosa hybrida, 'Jumilia' and 'Samurai', under supplementary lighting, light-emitting diode (LED) panels equipped with R (red), B (blue), and F-R (far-red) LEDs (60:30:10%) in two light intensities of LED75 and LED150 μmol m−2 s−1 PPFD (photosynthetic photon flux density) were applied and compared with high-pressure sodium (HPS) and metal halide (MH) lights (emitting 150 μmol m−2 s−1 PPFD) and without supplemental lighting as the control condition in a greenhouse during the short days on hydroponically cultured roses. Flower morphology and physiological and biochemical changes, flower endogenous ethylene production at harvest, changes in flower water uptake, and postharvest longevity along the shelf-life were determined. The results showed LED-exposed roses under 75 or 150 μmol m−2 s−1 PPFD had higher plant height, leaf area, and leaf chlorophyll, carotenoid, and soluble carbohydrates contents, as compared to the other light sources. A higher number of flowers and a lower chlorophyll/carotenoid proportion allocated to leaves were measured under mixed LEDs than those exposed to HPS, MH, and control conditions. Cut roses treated with LED lighting also had improved quality and performance in terms of postharvest life longevity, showing delayed senescence symptoms due to higher water uptake and less ethylene production than other light treatments. It is concluded that LED light exposure improves the postharvest life of cut rose flowers by affecting the roses' physiological parameters. These results may extend further development towards integrating LED technology in the cut rose flower distribution chain from greenhouse to storage facilities. [ABSTRACT FROM AUTHOR] |
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