Mitigation Effects of Water-soluble Chitosan on Boron Toxicity in Pepper Plants

Excess boron in soil is often found in dry agricultural areas and is one of the factors limiting crop yields. Polysaccharide-based biostimulants can mitigate the harmful effects of environmental stresses on plants. I performed this study under controlled greenhouse conditions to understand the response of pepper plants under boron stress to treatment with water-soluble chitosan (WSC). I watered plants with 50 or 100 mg/l WSC and 1.5 mM boric acid solution. As a result of WSC application at both concentrations, plants were taller and had more leaves and greater leaf length, width, relative chlorophyll content, and fresh aboveground weight compared with the control. Plants exposed to boron stress had fewer leaves, a lower relative chlorophyll content, and leaf blade damage indicative of boron toxicity. At the same time, boron-exposed plants showed a marked increase in the leaf nitrogen, phosphorus, potassium, and boron contents. Applying WSC at both concentrations modulated boron stress in plants by improving plant growth; reducing boron accumulation in leaves; and increasing the available nitrate nitrogen, phosphorus, and potassium contents in the substrate.