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.
