LAUSR

The innovative LED light source (Sun Box) with irradiation spectrum close to the sun spectrum in the wavelength range 440-660 nm was used in experiment for study the influence of light intensity (75, 135, 230 and 382 μmol/s*m2) on the growth and development of plants. Standard fluorescent lighting was used as a control. The experiments were carried out on plantlets of Stevia rebaudiana and Solanum tuberosum, cvs. Snegir, Rozhdestvenskiy and Kamchatskii) in vitro. The illumination intensity of 75 and 230 μmol/s*m2 promoted development of S. rebaudiana plantlets with optimal values of morphometric parameters and well developed roots, which is important for plantlet adaptation to soil conditions. For S. tuberosum plantlets (Snegir and Rozhdestvenskiy cultivars), radiation intensity of 135 μmol/s*m2 was optimal for micropropagation. The illumination intensity of 230 μmol/s*m2 led to a formation of plantlets with the largest total fresh mass among experimental groups. Sun Box light with intensity of 75 μmol/s*m2 could be applicated for micropropagation of these cultivars: plantlets were the highest with the largest internodes number. Thus, the plant response to different light intensity was species-spesific, and – in case of potato plantlets – cultivar-spesific. The use of artificial light sources with distinct PPFD level could be preferable for S. tuberosum and S. rebaudiana plantlet micropropagation in vitro, as it could shorten the cultivation time, accelerate cultivation time, and reduce the cost of electricity.