Effect of pulsed and scanning LED irradiation on physicochemical parameters of Japanese cabbage of the Mizuna Red variety

Abstract

When growing plants in light culture, particularly effective are energy-saving LED irradiators with long service life, low heat dissipation and small size, as well as an ability to be closely located to the plants and possibility of regulating the intensity and spectrum of illumination. To evaluate the effect of irradiation modes on plants and energy expenditure under these regimes, the productivity of plant products of Japanese cabbage variety Mizuna Red and their biochemical composition were studied. Plants were illuminated by specially designed LED lamps produced by VIM with a dynamically adjustable spectral composition in four channels. Experimental studies were conducted under three radiation modes: continuous (control), pulsed and scanning with a total photosynthetic active radiation of 321 μmol/m²s in the proportion of B:G:R:FR ~ 30:26:38:6. Parameters of aboveground mass and dry matter formation were determined twice on the 15th and 30th days of the growing season. It was found that under the pulsed radiation mode the content of dietary fibres in leaves compared to continuous illumination (control) is 64.3% higher, and ash content – 19.1% higher. The increased content of ascorbic acid and choline has also been noted. The application of the pulsed mode of radiation increased the content of carbohydrates in the tissues of Mizuna Red shoots by 71.4% as compared to the scanning mode.