Seed priming with chitosan nanoparticles improved seed vigour parameters and antioxidant enzyme kinetics under...

Global cotton production often experiences significant obstacles from climatic variability, particularly due to drought stress. The present study evaluated the efficacy of seed priming with chitosan nanoparticles (CNPs) as a sustainable strategy to mitigate drought stress in cotton under rainfed ecology of cotton cultivation in India. The laboratory synthesized chitosan nanoparticles using the ionic gelation method with trisodium polyphosphate (TTP) as a crosslinker were characterized through transmission electron microscopy (Joel JEM 2100 Plus) and particle size analyser (Malvern Zetasizer Nano ZS90). Bt-cotton (Bacillus thuringiensis derived toxin; GMO cotton) seeds were then subjected to hydropriming and 200 ppm chitosan nanoparticles (CNPs) priming along with an untreated control under laboratory conditions at ambient temperature (27 °C) with three independent runs. Seedling growth parameters, seed vigour indices, germination (%) and key biochemical markers such as total protein content, catalase, superoxide dismutase and peroxidase enzyme activity were recorded under varying PEG (polyethylene glycol) induced stress conditions. Our findings highlighted that CNPs priming significantly enhanced all vigour parameters under optimal (no stress) conditions. Chitosan nanoparticle (CNPs) primed seedlings maintained significantly higher root length (10.80 cm), shoot length (11.27 cm), dry weight (823.33 mg), and germination percentage (96.33%) under 5% PEG stress, compared to hydro primed and untreated seeds. This enhanced performance may be attributed to significantly higher total protein content and higher catalase and peroxidase activity in CNPs primed seeds. The positive effects of CNPs were further validated in the soil tube experiment with moisture level of 100%, 75% and 60% field capacity, demonstrating enhanced root and shoot development with chitosan priming under lowered Field capacity compared to untreated seeds. Seed priming with CNPs offers a sustainable strategy for drought tolerance in cotton, promoting seed vigour traits and pre-activating biochemical responses. This chitosan nanoparticle seed priming approach is highly promising for enhancing crop resilience in water scarce environments.