Photosynthetic effects of light-emitting diode (LED) on in vitro-derived strawberry (Fragaria x Ananassa cv. Festival) plants under in vitro conditions

Abstract

Purpose of this study was to investigate effect of different photosynthetic photon flux density (PPFD) conditions using LED lamps on culture of shoot explants derived from in vitro shoots of Fragaria x ananassa cv. Festival. To examine the combined effect of 55% red LED, 15% far red LED, 10% blue LED, 15% green LED and 5% warm light LED light on in vitro growth of plantlets, fresh and dry plant biomass, plant height, leaf area, number of shoot, shoot length, number of root and percentage of rooting and various growth of micro-propagated plants were assessed under four light intensities (25, 50, 75 and 100 μmol m−2 s−1 PPFD; TRT2, TRT3, TRT4, TRT5, respectively). Un-rooted strawberry shoots were cultured in the “Culture Pack”-rockwool system with MS medium under CO2-enriched condition. The best response for regeneration of shoots and root induction was observed for shoot explants obtained on MS supplemented with BAP 1mg/l and NAA 0.5 mg/l at TRT3 (50 μmol m−2 s−1 PPFD). Chlorophyll and net photosynthesis were optimal in plants grown under TRT4 (75 μmol m−2 s−1 PPFD). Stomatal resistance and Fv/Fm values were highest at low light irradiance (TRT2). The highest efficiency and high frequency of shoot formation occurred after 30 days. Elongation of shoot buds was obtained at TRT4 (75 μmol m−2 s−1 PPFD) and TRT5 (100 μmol m−2 s−1 PPFD) on the same MS medium. Regenerated shoots rooted best on the same medium of elongation. Irradiance at 75 μmol m−2 s−1 PPFD was suitable for the acclimatization of strawberry plants. We concluded that the present protocol can be efficiently used for mass propagation of the strawberry.