How Light Spectrum and Light Intensity Using Mixed LEDs Affect the Growth of Populus F1-3 g14 Hybrid and Callus Morphology In Vitro
摘要
The development of light-emitting diode (LED) technologies currently allows their use in plant growth regulation. Our purpose was to evaluate the influence of different light intensities and spectra ratios of mixed LEDs on morphogenesis, accumulation of photosynthetic pigments, and callus in the hybrid Populus F1-3g14 cultivated in vitro. The study’s object was a drought-resistant and fast-growing hybrid Populus F1-3g14, which was obtained from targeted crossing of Populus deltoides W. Bartram and Populus alba L., and was selected as an example. Analysis of the influence of the six spectral ratios of LEDs in the range of photosynthetic photon flux density (PPFD) from 20 to 225 μmol m−2 s−1 was carried out to determine the optimal growth parameters and morphogenesis of regenerants and calluses of the Populus F1-3g14 hybrid in vitro culture. All the samples were grown under strictly controlled conditions on 15 varieties of lighting combinations with a 16-h photoperiod on nutrient media according to the Murashige and Skoog protocol without the addition of growth regulators. The determination of parameters such as the length and growth of the shoot, the length and number of roots, the percentage of rooting, fresh masses of shoot, root, primary callus, and morphometric parameters of the leaf plate, as well as the studied pigment composition made it possible to choose optimal lighting conditions. The combination of R:B:G spectra (1:1:0.5) and an intensity of 70 μmol m−2 s−1 is optimal for the propagation of the Populus F1-3g14 hybrid, and the highest rooting percentage was noted at the R:B:G ratio (2.5:1:0.4) and an intensity up to 70 μmol m−2 s−1 on the complete composition of the hormone-free nutrient medium MS. Our results provide valuable recommendations for the application of strategies involving the use of light spectra for growth of Populus F1-3g14 hybrids in vitro.