Modern agriculture cannot be imagined without the introduction of smart and efficient technologies. These, undoubtedly, include technologies for directed regulation of the illumination of agricultural plants. Depending on the climatic conditions of cultivation, farmers shade or additionally illuminate the plants, and also change the spectrum of the light reaching the plants. The aim of this review is to provide an overview of solar light conversion methods and approaches for agricultural applications and discuss their advantages and limitations.

It has been shown that the cultivation of plants under glass coated with nano-sized upconversion luminophores led to an increase in plant productivity and the acceleration of plant adaptation to ultraviolet radiation. In the present work, we examined the effect of upconversion nanopowders with the nominal composition Sr_0.955Yb_0.020Er_0.025F_2.045 on plant (Solanum lycopersicum) photochemistry. The composition, structure and size of nanoparticles were tested using X-ray pattern diffraction, scanning electron microscopy, and dynamic light scattering. Nanoparticles are capable of converting infrared radiation into red and green photons. Glasses coated with upconversion luminophores increase the intensity of photosynthetically active radiation and absorb the ultraviolet and far-red radiation. The chlorophyll a fluorescence method showed that plants growing under photoconversion and those growing under common film demonstrate different ability to utilize excitation energy via photosynthesis. It was shown that under ultraviolet and high light conditions, the efficiency of the photochemical reactions, the non-photochemical fluorescence quenching, and the electron transport remained relatively stable in plants growing under photoconversion film in contrast to plants growing under common film. Thus, cultivation of Solanum lycopersicum under photoconversion glasses led to the acceleration in plant growth due to greater efficiency of plant photochemistry under stress conditions.

On the basis of a direct current magnetron, a technology has been developed for producing nanoscale-oriented nanorods from zinc oxide on an acrylic polymer. The technology makes it possible to achieve different filling of the surface with zinc oxide nanorods. The nanorods is partially fused into the polymer; the cross section of the nanorods is rather close to an elongated ellipse. It is shown that, with intense abrasion, no delamination of the nanorods from the acrylic polymer is observed. The zinc oxide nanorods abrades together with the acrylic polymer. Zinc oxide nanorods luminesces with the wavelength most preferable for the process of photosynthesis in higher plants. It was shown that plants grown under the obtained material grow faster and gain biomass faster than the control group. In addition, it was found that on surfaces containing zinc oxide nanorods, a more intense formation of such reactive oxygen species as hydrogen peroxide and hydroxyl radical is observed. Intensive formation of long-lived, active forms of the protein is observed on the zinc oxide coating. The formation of 8-oxoguanine in DNA in vitro on a zinc oxide coating was shown using ELISA method. It was found that the multiplication of microorganisms on the developed material is significantly hampered. At the same time, eukaryotic cells of animals grow and develop without hindrance. Thus, the material we have obtained can be used in photonics (photoconversion material for greenhouses, housings for LEDs), and it is also an affordable and non-toxic nanomaterial for creating antibacterial coatings.

The effect of upconverting luminescent nanoparticles coated on glass on the productivity of Solanum lycopersicum was studied. The cultivation of tomatoes under photoconversion glass led to an increase in plant productivity and an acceleration of plant adaptation to ultraviolet radiation. An increase in the total leaf area and chlorophyll content in the leaves was revealed in plants growing under the photoconversion glass. Plants growing under the photoconversion glass were able to more effectively utilize the absorbed light energy. The results of this study suggest that the spectral changes induced by photoconversion glass can accelerate the adaptation of plants to the appearance of ultraviolet radiation.

In the present work, we investigated the effect of light conversion using europium (Eu(III))-based photoconversion covers on the cultivation of agricultural plants and their resistance to stress conditions. Two types of europium nanoparticles were used. The first one was obtained from europium oxide (Eu₂O₃) by laser fragmentation. The second one was Eu³⁺:LaF₃ nanocrystals obtained by hydrothermal-microwave treatment, the content of europium ions in which was 50% of the total amount of cations. Tomatoes (Solanum lycopersicum) and cucumbers (Cucumis sativus) were used as model plants. It was shown that plants grown under cover with Eu₂O₃ (PCC-Eu₂O₃) were 30–40% larger, gave a higher yield, and the activation of gas exchange processes and the light phase of photosynthesis in the leaves in response to the lighting was faster. On the contrary, plants grown under cover with Eu³⁺:LaF₃ (PCC-Eu³⁺:LaF₃) tended to slow down the rate of biomass accumulation and decrease the rate of gas exchange activation. It was shown that photoconversion covers change the resistance of plants to stress conditions: if plants grown under PCC-Eu₂O₃ became more sensitive to heat (+40 °C) and cold (+4 °C) treatment, then plants grown under PCC-Eu³⁺:LaF₃ became more resistant to high and low temperatures. It was found that PCC-Eu₂O₃ inhibited the development of the phytopathogen Phytophthora infestans on tomato plants. It was assumed that changes in the illumination spectrum by the photoconversion covers cause both the activation of plant growth in the case of Eu₂O₃ and an increase in plant resistance in the case of Eu³⁺:LaF₃ applications.

A method for stimulating the growth of spruce and strawberry in the early phases of development is proposed. A technology for obtaining plasma-activated water (PAW) with the help of a glow discharge plasma generator was developed. The method is proposed for increasing the shelf life of PAW by adding an aqueous colloid of polyvinylpyrralidone (PVP) polymer. It is shown that after treatment with a PAW + PVP mixture, the seeds have a higher percentage of germination, the plants develop faster in the early stages, and they are more viable. At the physicochemical level, after seed treatment with PAW + PVP, higher rates of metabolite outflow from seeds are observed. At the biological level, seed treatment with PAW + PVP leads to a slight decrease in the activity of antioxidant enzymes and a higher content of chlorophylls in the leaves, and a slightly higher assimilation rate is observed. In the leaves, there is higher content of the growth hormone indole-3-acetic acid (IAA), whereas the content of the growth-inhibiting hormone abscisic acid decreases. The use of a stimulating drug based on the composition of an aqueous solution activated by plasma and polyvinylpyrrolidone (PAW + PVP) polymer can be an effective means of a single pre-sowing treatment of spruce seeds in solving the problem of reforestation and strawberry during plant propagation.