Reaction of Oat Plants to the Presence of Aluminum Nanoparticles in the Nutrient Substrate

Aluminum is widespread in the earth’s crust and is widely used in human economic activity, but its physiological functions in plants have not been fully clarified. The direction of the influence of various concentrations of aluminum nanoparticles on the growth and development of plants, as well as the features of physiological and biochemical processes in them, remain insufficiently studied. The reaction of common oat (Avena sativa L.) to the presence of aluminum nanoparticles in the plant growing substrate was studied under the conditions of a pot experiment. The introduction of aluminum nanoparticles into the substrate at concentrations of 100 and 1000 mg/kg reduces the content of chlorophylls a and b in the leaves at the early stages of plant development. At the same time, at the heading and milky ripeness stages, the amount of chlorophylls and carotenoids increases in the variants using nanoparticles. Changes in the content of photosynthetic pigments indicate a restructuring of the adaptive mechanisms of plants in the presence of aluminum nanoparticles. In the main stages of oat development (tillering, heading, milky ripeness), the chlorophyll ratio (a/b) was within 2.1–3.2, which indicates compensated work of the pigment complex in the presence of nanoparticles in the substrate. During the main development phases, oats grown in the presence of increasing doses of aluminum nanoparticles (10, 100 and 1000 mg/kg) showed a reliable decrease in catalase activity and an increase in peroxidase activity in the leaves and roots of plants. The identified trends in the change in the activity of antioxidant enzymes indicate the reaction of the plant organism to unfavorable environmental factors. The content of aluminum nanoparticles in the oat growing substrate at a concentration of 1000 mg/kg leads to a decrease in the root mass in the tillering phase, as well as the aboveground mass of plants in the tillering, heading and milk ripeness phases. The height of plants, the length of inflorescences, the number and weight of grains also decrease, which indicates a negative impact of high concentrations of aluminum nanoparticles on the production process.