Abstract
In recent years, the light emitting diodes (LED) have become an alternative to the fluorescence lamp source of light for plant tissue culture, due to their low energy consumption, low heat emission, specific wavelength irradiation etc. The aim of this study was to investigate the effect of LEDs on the growth of in vitro cultivated raspberry (Rubus idaeus L. ‘Lloyd George’). The plantlets were cultivated in vitro under an illumination system based on Philips GreenPower LED research module. Four groups of LEDs emitting in white (W), red (R), blue (B), mixed (W:R:B:far-red=1:1:1:1) lights and fluorescent lamps (control) were used in our studies. Growth parameters, some physiological and biochemical characteristics of the plantlets were measured after three four weeks passages under corresponding light treatment. Our results indicated that different LEDs specifically influence the growth and development of in vitro cultivated raspberry plantlets and could be applied as an efficient lighting system for rapid in vitro micropropagation of Rubus idaeus L. The combination of blue, red, far red and white LEDs (1:1:1:1) stimulated the growth and biomass accumulation, as well as the intensity of net photosynthesis. For optimal results, it would be advisable to shorten the culture period to 3 weeks. This effective and affordable protocol would support the commercial micropropagation of raspberries and other soft fruits.
Keywords: micropropagation, shoot culture, LED, light quality, photosynthetic pigments, chlorophyll fluorescence.