Effect of Selenium Nanocomposites Based on Natural Polymer Matrices on the Biomass and Storage of Potato Tubers in a Field Experiment

The effect of chemically synthesized selenium (Se) nanocomposites (NCs) based on the natural polymer matrices arabinogalactan (AG), carrageenan (CAR), and starch (ST) on potato tuber traits, storage, and crop structure was studied in a field trial. Parental potato tubers were sprayed by Se/AG NC, Se/ST NC, and Se/CAR NC 14 days before planting in the field. The results showed that Se/AG NC and Se/CAR NC increased the number and weight of tubers in the first generation (F1) obtained from the plants grown from the treated tubers. It was found that Se/AG NC and Se/ST NC decreased the median weight of shoots after 230 days of storage of the F1 tubers, preventing their premature germination, and Se/AG NC decreased the number of rotten tubers. All three Se NCs significantly improved the storage by increasing the number of healthy scab-, dry-pitted-rot-, and wireworm-free tubers in the F1 after 230-day-long storage, except Se/CAR NC regarding dry pitted rot. Selenium/ST NC significantly increased the number of tubers, and Se/CAR NC their mass, and both decreased the number of rotten tubers in the second generation (F2). Selenium NCs affected crop structure in both generations

Effect of Selenium Nanocomposites Based on Natural Polymer Matrices on the Biomass and Storage of Potato Tubers in a Field Experiment

The effect of chemically synthesized selenium (Se) nanocomposites (NCs) based on the natural polymer matrices arabinogalactan (AG), carrageenan (CAR), and starch (ST) on potato tuber traits, storage, and crop structure was studied in a field trial. Parental potato tubers were sprayed by Se/AG NC, Se/ST NC, and Se/CAR NC 14 days before planting in the field. The results showed that Se/AG NC and Se/CAR NC increased the number and weight of tubers in the first generation (F1) obtained from the plants grown from the treated tubers. It was found that Se/AG NC and Se/ST NC decreased the median weight of shoots after 230 days of storage of the F1 tubers, preventing their premature germination, and Se/AG NC decreased the number of rotten tubers. All three Se NCs significantly improved the storage by increasing the number of healthy scab-, dry-pitted-rot-, and wireworm-free tubers in the F1 after 230-day-long storage, except Se/CAR NC regarding dry pitted rot. Selenium/ST NC significantly increased the number of tubers, and Se/CAR NC their mass, and both decreased the number of rotten tubers in the second generation (F2). Selenium NCs affected crop structure in both generations

Selenium Nanocomposites in Natural Matrices as Potato Recovery Agent

The paper presents a study of the effect of chemically synthesized selenium nanocomposites (Se NCs) in natural polymer matrices arabinogalactan (AG) and starch (ST) on the viability of the potato ring rot pathogen Clavibacter sepedonicus (Cms), potato plants in vitro, and the soil bacterium Rhodococcus erythropolis. It was found that the studied Se NCs have an antibacterial effect against the phytopathogenic Cms, reducing its growth rate and ability to form biofilms. It was revealed that Se NC based on AG (Se/AG NC) stimulated the growth and development of potato plants in vitro as well as their root formation. At the same time, Se did not accumulate in potato tissues after the treatment of plants with Se NCs. The safety of the Se NCs was also confirmed by the absence of a negative effect on the growth and biofilm formation of the soil bacterium R. erythropolis. The obtained results indicate that Se NCs are promising environmentally safe agents for the protection and recovery of cultivated plants from phytopathogenic bacteria

Effect of Natural Polysaccharide Matrix-Based Selenium Nanocomposites on Phytophthora cactorum and Rhizospheric Microorganisms

We studied the effects of new chemically synthesized selenium (Se) nanocomposites (NCs) based on natural polysaccharide matrices arabinogalactan (AG), starch (ST), and kappa-carrageenan (CAR) on the viability of phytopathogen Phytophthora cactorum, rhizospheric bacteria, and potato productivity in the field experiment. Using transmission electron microscopy (TEM), it was shown that the nanocomposites contained nanoparticles varying from 20 to 180 nm in size depending on the type of NC. All three investigated NCs had a fungicidal effect even at the lowest tested concentrations of 50 µg/mL for Se/AG NC (3 µg/mL Se), 35 µg/mL for Se/ST NC (0.5 µg/mL Se), and 39 µg/mL for Se/CAR NC (1.4 µg/mL Se), including concentration of 0.000625% Se (6.25 µg/mL) in the final suspension, which was used to study Se NC effects on bacterial growth of the three common rhizospheric bacteria Acinetobacter guillouiae, Rhodococcus erythropolis and Pseudomonas oryzihabitans isolated from the rhizosphere of plants growing in the Irkutsk Region, Russia. The AG-based Se NC (Se/AG NC) and CAR-based Se NC (Se/CAR NC) exhibited the greatest inhibition of fungal growth up to 60% (at 300 µg/mL) and 49% (at 234 µg/mL), respectively. The safe use of Se NCs against phytopathogens requires them to be environmentally friendly without negative effects on rhizospheric microorganisms. The same concentration of 0.000625% Se (6.25 µg/mL) in the final suspension of all three Se NCs (which corresponds to 105.57 µg/mL for Se/AG NC, 428.08 µg/mL for Se/ST NC and 170.30 µg/mL for Se/CAR NC) was used to study their effect on bacterial growth (bactericidal, bacteriostatic, and biofilm formation effects) of the three rhizospheric bacteria. Based on our earlier studies this concentration had an antibacterial effect against the phytopathogenic bacterium Clavibacter sepedonicus that causes diseases of potato ring rot, but did not negatively affect the viability of potato plants at this concentration. In this study, using this concentration no bacteriostatic and bactericidal activity of all three Se NCs were found against Rhodococcus erythropolis based on the optical density of a bacterial suspension, agar diffusion, and intensity of biofilm formation, but Se/CAR and Se/AG NCs inhibited the growth of Pseudomonas oryzihabitans. The cell growth was decrease by 15–30% during the entire observation period, but the stimulation of biofilm formation by this bacterium was observed for Se/CAR NC. Se/AG NC also had bacteriostatic and antibiofilm effects on the rhizospheric bacterium Acinetobacter guillouiae. There was a 2.5-fold decrease in bacterial growth and a 30% decrease in biofilm formation, but Se/CAR NC stimulated the growth of A. guillouiae. According to the results of the preliminary field test, an increase in potato productivity by an average of 30% was revealed after the pre-planting treatment of tubers by spraying them with Se/AG and Se/CAR NCs with the same concentration of Se of 0.000625% (6.25 µg/mL) in a final suspension. The obtained and previously published results on the positive effect of natural matrix-based Se NCs on plants open up prospects for further investigation of their effects on rhizosphere bacteria and resistance of cultivated plants to stress factors