ISHS Acta Horticulturae 272: Symposium on Bedding and Pot Plant Culture
PREVENTION OF PHYTOCHROME-RELATED POSTHARVEST LOSS OF QUALITY IN ORNAMENTALS THROUGH RED LIGHT EMITTED BY DIODES |
| Authors: | M.J. van Lieburg, W.G. van Doorn, H. van Gelder |
| Abstract:
Loss of quality during transport and storage of plants in the dark may be due to short-term phytochrome-related processes. Cut flowers of Alstroemeria pelegrina L. cv. Yellow King held in water and kept in the dark for nine days at 20°C showed leaf yellowing. Red light during this period resulted in higher total chlorophyll content than dark treatment (112 and 72 mg/100 g fresh weight resp.). Far-red light completely nullified the effect of red light. Hibiscus rosa-sinensis L. cv. Nairobi plants kept in the dark for four days at 20°C lost 74% of all flower buds; this could be reduced to 31% by red light. Far-red light reversed the effect of red light to 91%. Red/far-red reversal was established by a 30/45 sec red/far-red regime and a 30/45 sec red/dark regime, applied continuously during the experiment. Red light emitting diodes (660 nm peak, 3.3 μmol m-2.s-1 in the 635–685 range) were mounted in filters implemented to produce the far-red fraction from incandescent light. This enabled convenient alternation of the two action spectra in one system. Heat production is a main obstacle for applying light during transport or storage of ornamentals. Use of light emitting diodes prevents heat build-up. Compared to fluorescent tubes and incandescent lamps, red light emitting diodes are six times more efficient in converting electrical energy to photon flux density in the 635–685 nm range. | |
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