Lighting conditions are an important controller of plant growth and development, and they affect secondary metabolite synthesis. In this research, we explored the effect of additional UV irradiation of various ranges in addition to the main one at PPFD 160 µmol m⁻² s⁻¹ on the accumulation of some secondary metabolites of stevia (Stevia rebaudiana Bertoni). The fresh weight of leaves was slightly higher under additional UV-A and UV-B irradiation compared with the control variant, and the leaf surface area was significantly larger, respectively, by 23.3 and 20.7% than in the control variant, while the rate of photosynthesis did not decrease. Plants under additional UV-B and UV-C irradiation were under the greatest light stress, as evidenced by a decrease in antioxidant capacity by an average of 30% compared to the control and UV-A. The total flavonoid content was significantly higher (by 74%) under UV-B irradiation. The highest concentration of steviol glycoside was observed during budding and flowering under UV-B and UV-C irradiation (by 13.2 and 11.3%, respectively). Analysis of hyperspectral images, chlorophyll fluorescence, and vegetation indices showed light stress increasing under UV-C irradiation, which caused an increase in the relative chlorophyll content, scorches, leaf morphology changes, a CO₂ absorption rate decrease, and plant growth inhibition. UV-B irradiation can be used as an optimal type of irradiation based on a set of indicators.

The dependence of the efficiency of extraction of micro and macronutrients Mg, Fe, Zn, Mn, Cu, Mo B, K, Ca, P in the leaves and fruits of cucumber, tomato and red leaf lettuce on the emission spectrum of LED emitters and sodium lamp during cultivation on hydroponics was studied. The extraction coefficient, equal to the ratio of the content of elements in the leaves to their concentration in the nutrient solution, for trace elements depended mainly on the plant species, and for macronutrients – on the spectrum of the irradiator. When constructing the physicochemical model of the extraction of mineral elements have taken into account the dependence of the efficiency of photosynthesis from the external electric field, and polarizing and orienting effects in the conductive medium of the plants of charged metabolites and pigments that have dipoles in the ground and electronically excited states. It was suggested that the efficiency of extraction of elements depends on the coordination number, the electric charge, the mass and the radius of the ion. The extraction coefficients were linearly dependent on a physically based combination of these parameters and the slopes of their trends corresponded to changes in the extraction efficiency from the irradiator spectrum and plant species.

In this work, we synthesized Mn⁴⁺-doped CaSb₂O₆ phosphors using the conventional solid-state reaction method for plant growth lighting applications. The morphological, structural, and optical properties were analyzed based on the results obtained from scanning electron microscope, X-ray diffraction, and spectrophotometer. The results of the spectrophotometer illustrate that the phosphors showed a red emission band in 550–800 nm wavelength range with peak maxima at 642 nm. The red emission in these phosphors is attributed to the ²E_g → ⁴A_2g transition of Mn⁴⁺ ions. The emission intensity is increased with the doping of a charge compensator. The emission range of the phosphor covers the absorption range of photosynthetic pigments such as chlorophyll a, chlorophyll b, phytochrome P_r, and phytochrome P_fr. The results signify that the prepared phosphor materials are suitable candidates for application in plant growth lighting.

This chapter describes how with the artificial cultivation of plants lamps are required with a certain spectrum of radiation. For lighting plants have developed a special lamp. Industry produces special gas discharge lamp. In these lamps a fixed range of radiation. Recently, there were light sources for plants on LEDs. LEDs can create light with any spectrum range from 360 to 800 nm. The authors of the article give a technique for modeling the spectrum of luminaires and calculating LED lamps for plants. The tests of the developed lamps for plants in dark chambers are given. A description of a resonant regulated power supply system for LED luminaires is given. In the proposed system when the frequency changes radiation power.