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In this work, we investigated the effect of photoconversion covers based on ruby (chromium-doped alumina (Al2O3:Cr3+)) particles (PCC-R) on the growth and development of lettuce (Lactuca sativa) plants. Ruby particles (from 100 nm to 2 μm) were obtained by the sequential application of spall laser ablation and further laser fragmentation. The content of chromium ions relative to aluminum ions in the nanoparticles was 3.3 × 10−3. The covers with different densities of applied ruby particles (2 × 107 m−2 (PCC-R7), 2 × 108 m−2 (PCC-R8), 2 × 109 m−2 (PCC-R9)) were studied in the present work. The PCC-Rs had two wide bands of luminescence excitation. The first one was from 350 nm to 450 nm with a maximum at 405 nm, and the second one was from 500 nm to 600 nm with a peak at 550 nm. Synthesized covers emitted in the range of 650 nm to 750 nm, with a peak at 695 nm. It has been shown that PCC-R8, in contrast to PCC-R7 and PCC-R9, provided an increase in yield by 40% and was characterized by increased water use efficiency during dark respiration and assimilation of carbon dioxide in plants. It is assumed that the observed positive effect of PCC-R8 photoconversion covers is associated with the activation of regulatory mechanisms due to a qualitative change in the light spectrum. [ABSTRACT FROM AUTHOR]

The effect of graphene oxide-based photoconversion covers on the growth and photosynthesis of tomatoes (Solanum lycopersicum) was investigated. Two types of photoconversion composite for covers were produced. In the first, only graphene oxide nanoparticles were used as a phosphor, and in the second, the graphene oxide nanoparticles were used jointly with europium oxide nanoparticles. The freshly prepared composites for covers had almost identical photoluminescence spectra: an intense peak in the red region and a minor peak in the blue region. It was revealed that during operation, luminescence in the red region decreased, while in the blue region it increased, probably due to the photothermal reduction of graphene oxide. It was shown that the photoconversion covers increased productivity (25%) and intensified photosynthesis (30–35%) in the tomato plants. It is suggested that the stimulation of plant growth is caused by changes in the light spectrum induced by the photoconversion covers. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The search for environmentally neutral construction materials is an important aim of science from the middle of the XX century. We elaborated the method of the smelting of the new alloy Ti-20Nb-10Ta-5Zr. The Ti-20Nb-10Ta-5Zr was a β-phase alloy with an ~550 MPa yield strength, an ~700 MPa of ultimate strength and >50 GPa Young's modulus. The Ti-20Nb-10Ta-5Zr alloy did not generate reactive oxygen species in contradistinction to the widely used NiTi. The biocompatibility of Ti-20Nb-10Ta-5Zr was studied. The human cell line cultured on the alloy showed a high mitotic index (2.2%) and a low cytotoxicity (<4% dead cells). The 30 days of the cultivation of the plants near the Ti-20Nb-10Ta-5Zr blanks did not influence the morphology and plants area. Therefore, Ti-20Nb-10Ta-5Zr may be considered as a material for the manufacture of environmentally neutral greenhouses of a new generation. [ABSTRACT FROM AUTHOR]

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 Sr0.955Yb0.020Er0.025F2.045 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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The influence of light conversion induced by glasses coated with up-converting luminescent nanoparticles on Solanum lycopersicum cultivation was studied. Nanoparticles of Sr0.46Ba0.50Yb0.02Er0.02F2.04 solid solution were used as the up-converting luminophore. These nanoparticles were able to transform IR radiation into visible light (λem = 660 nm with minor peaks at 545 nm and 525 nm). By applying the "variable" chlorophyll fluorescence (ΔF), it was shown that the cultivation of tomatoes under the photoconversion glasses stimulated changes in the rate of plant adaptation to ultraviolet radiation. The restoration time of values of effective quantum yield of photosystem II photochemical reactions and photochemical quenching of chlorophyll fluorescence (reflecting disappearance of imbalance between photosynthetic electron transport and the utilization of NADPH) was reduced from three weeks to three days in the case of control and photoconversion films, respectively. As a result, plants grown under photoconversion glass had an increased leaf number (12.5%), total leaf area (33%), stem length (35%) and chlorophyll content in the leaves (two-fold). It is assumed that an increase in the proportion of red light in the growing spectrum has a positive effect on photosynthetic activity and plant growth. [ABSTRACT FROM AUTHOR]