The importance of additional illumination in the cultivation of grafted cucumber seedlings and potato seedlings from botanical seeds

Relevance. Plants use light not only as an energy source for photosynthesis, but also as an important regulator of their growth and development. The characteristics of light, such as intensity, spectral composition, duration of illumination, as well as the characteristics of the luminous flux, play a key role in the physiological processes of plants. Therefore, it is important to work out the lighting modes necessary for the growth of various plant species in order to control their metabolic processes.
Material and methodology. In the work, grafted seedlings of Kabeiri F₁ cucumber on the rootstock of a Lagenarium and potato seedlings obtained from botanical seeds of domestic and foreign varieties were simultaneously studied as objects of research: Gulliver, Luck, Vineta, Bellorosa, Riccarda, Indigo. The two crops were grown under light culture conditions with a day duration of 12.14 and 16 hours. LED lamps with blue (440-445 nm) and red (660-665 nm) spectra were used to illuminate the plants in the following ratios: 60/40, 50/50 and 40/60. The studies were carried out in three repetitions of 20 registered plants. The technology of growing plants in protected soil is generally accepted for the Volgograd region.
Results. When assessing the effect of bicolor illumination of a grafted cucumber, the R60B40 ratio turned out to be the most suitable, it contributed to the active development of the vegetative part, and an increase in the photoperiod to 14-16 hours prevented the extension of the internodes by 2.0 cm and the subsameral knee at the rootstock. The prevalence of the blue spectrum had a negative effect on the grafted seedlings: a decrease in growth activity, a reduction in the length of the internodes, and with a day length of 16 hours, the tip of the growth point. When assessing the development of the vegetative part of potato seedlings obtained from botanical seeds, it is possible to note a similar reaction of the tops as in the grafted Kabeiri F1 cucumber. However, when assessing the yield of mini tubers, it was the predominance of the blue spectrum that increased the yield percentage to 26.1% with a photoperiod of 16 hours.

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