Optimizing Saccharum species hybrid plantlets growth in vitro by using different photon flux density and wavelengths in photoautotrophic system (sugar-free medium)

Plantlets grown in vitro show different growth responses and photosynthetic pigment production when they are exposed to different light conditions. The aim of the present study is to assess the agronomic and physiological performance of sugarcane (Saccharum spp. hybrid) grown in vitro under different light intensity and spectrum variations. Plantlets measuring approximately 2 cm, grown in vitro, based on somatic embryogenesis, were cultivated in Murashige and Skoog (MS) basic medium and subjected to five light intensities: 26, 70, 100, 113 and 144 µmol m^− 2 s^− 1, at different light spectrums: 100% white, 100% red, 100% blue and blue/red combinations at %R: %B (30:70; 70:30; and 50:50) ratios obtained by LEDs, for 35 days. The optimal light intensity for maximizing dry weight and photosynthetic pigment production was 113 µmol m⁻² s⁻¹, which contributed to enhanced plantlet vigor. Furthermore, plantlets subjected to white, red, and blue light spectra showed the highest dry weight accumulation, while the 50% blue:50% red spectrum was most effective in promoting biosynthesis of photosynthetic pigments. In conclusion, this study demonstrated that the growth and physiological responses of sugarcane (Saccharum spp. hybrid) plantlets grown in vitro are significantly influenced by variations in light intensity and spectrum. These findings offer valuable insights for optimizing in vitro cultivation conditions to enhance sugarcane growth and development.