BIOCHEMICAL ASSESSMENT OF <i>EX VITRO</i> DEVELOPMENT OF GRAPE SEEDLINGS UNDER THE INFLUENCE OF LED SOURCES OF VARIOUS SPECTRAL COMPOSITION
With the help of biochemical methods (based on redox system condition of plants), we compared the impact from phyto-lamps (LED-sources of artificial illumination) with a different ratio of blue and red light fluxes on adaptation of grapevine seedlings in ex vitro conditions. It was revealed that, irrespective of the variety, the antioxidant defense mechanism in vine plants ex vitro under simulated conditions was most fully accomplished with the optimal ratio of blue and red light in the overall spectrum of the photon flux of photosynthetically active radiation (FAR) with a wavelength of 400-730 nm at a red / blue ratio (r/b) within 1.30-4.22. It was demonstrated that by biochemical criteria of stress resistance assessment, the spectral light composition of LED phyto-lamps with r/b ratio within 1.30 - 4.22 did not limit the development of seedlings ex vitro, while the r/b spectra ratio in this FAR range was not a stressor in grapevine adaptation under artificial lighting conditions. It was established that the activity of redox enzymes in the grapevine leaves and stress resistance of plants was largely genetic. Stress-resistant biologically adaptive grapevine varieties are characterized by higher redox enzyme activity (isoenzymes of peroxidase) and better adaptation mechanisms. The spectrophotometry data revealed high peroxidase activity in Marquette, Aladdin and Charlie varieties. The LED phyto-lamp models that we studied (LED sources) demonstrated potential suitability for adaptation of grapevine seedlings ex vitro, thereby enabling us to recommended them for use in the practice of grapevine nursery.