On the other hand, a high level of chitosan may not be effective because it can increase ABA via hydrogen peroxide signaling leading to: stomatal closure,; saturation of chitosan receptor molecules which are present in the cell membranes (Hidangmayum et al. 2019),; significant reduction of the cytoplasm; and a condensation of the chromatin, as well as increasing proteases activities (El Hadrami et al. 2010), and affecting. This will affect the root meristem, cellular polarity, and/or cyclin-dependent kinases, leading to disruption of root development (Asgari-Targhi et al. 2018). Therefore, it was hypothesized that various concentrations and application methods of chitosan would have different effects on Ni stress tolerance in soybean. Hence, the present research was designed and carried out to investigate the impact of chitosan application on improving Ni toxicity tolerance in soybean.
It seems that in foliar application of chitosan, its absorption and translocation to all parts of the plant was better. It is possible that the soil application of chitosan, has caused part of it to be fixed, insoluble, or bacterially degraded. Moreover, soil-applied chitosan is often effective in controlling soil pathogens in many plant species. Chitosan seed application also has the greatest effect on the germination and seedling growth stages of the plant, rather than other stages.
After thinning at the 2-leaf stage, six uniform seedlings were retained per pot, which; this was equivalent to 30 plants m-2, which is the optimal density of soybean in our region.