The application of hydrophilic polyvinyl alcohol coatings filled with different loadings of zinc oxide nanoparticles to mitigate salinity stress of the wheat seeds

In this work the effects of wheat seeds coating with polyvinyl alcohol (0 and 1.5 wt.%) and zinc oxide nanoparticles (0, 2, 4, and 6 wt.% of the amount of polyvinyl alcohol) under salinity stress (0 and 2 ds/m) to increase the seed resistance under non-biological stresses and to improve its productivity were studied. To evaluate the properties of the applied coating on the studied seeds, films consisting of polyvinyl alcohol and zinc oxide nanoparticles were also prepared and characterized by tensile tests, differential scanning calorimeter, Fourier transform infrared spectroscopy, Atomic force microscopy, moisture absorption, hardness, contact angle measurements, and scanning electronic microscope. A laboratory study was conducted as factorial in a completely randomized design with three replications to evaluate the germination indices. The films containing nanoparticles had a higher modulus and elongation at break. However, increasing the nanoparticles to 6 wt.% reduced the tensile strength by 29%. In addition, the application of nanoparticles caused an increase in film hardness, a decrease in moisture absorption, and an increase in contact angle. As results, the mechanical properties of the seed polymer coating were introduced as one of the most influential factors in seed germination performance. Regarding the effect of nanoparticles, zinc oxide nanoparticles significantly reduced the adverse effects of salinity stress.