Proline coated ZnO NPs as nanofertilizer against drought stress: an in vitro study to Coriandrum sativum

Key messageThe slow release of proline and zinc from ZnO-proline nanocomposite may mitigates drought stress for long time. Global efforts are rapidly evolving to address the challenges of climate change, including drought stress in crop systems. Nanotechnology offers its products to solve such problems. An in vitro experiment was carried out to evaluate the effect of proline-coated ZnO (ZnOP) NPs on coriander plants subjected to drought stress. Scanning electron microscopy (SEM) and powder X-ray diffraction (XRD) revealed nanoparticles with hexagonal structures of 14.73 nm (ZnO NPs) and 20.59 nm (ZnOP NPs). ZnOP NPs significantly improved the morphological parameters of plants grown under 5% and 10% PEG stress. ZnOP NPs increased shoot length by 11 cm and 15 cm and root length by 23 cm and 17 cm under 5% and 10% PEG induced drought stress plants, respectively. Dry weight also improved up to 1.94 g and 1.98 g under 5% and 10% PEG stress, respectively. The biochemical and antioxidant profile of the plants demonstrated the stress alleviating effect of ZnOP NPs. The contents of phenolics and flavonoids decreased with increasing concentration of NPs, indicating stress alleviation. At 100 mg/L, ZnOP NPs reduced the free radical scavenging activity in shoots by 62.97% and 71.94%, and in roots by 75.92% and 71.70% at 5% and 10% PEG stress, respectively. The total antioxidant profile decreased by 31% and 26% in shoots and by 23% and 43% in roots at 5% and 10% PEG, respectively. The improvement in the antioxidant enzyme also showed the stress reducing behaviour of ZnOP NPs. In conclusion, proline-containing ZnO NPs are effective in plants exposed to drought. These nanoparticles can be promoted as an effective strategy to overcome the harmful effects of drought stress in plants.

Automated summary

The slow release of proline and zinc from ZnO-proline nanocomposite can mitigate drought stress for a long time. Nanotechnology offers a solution to address the challenge of drought stress in crop systems. The experiment demonstrated that proline-coated ZnO nanoparticles significantly improved the morphological parameters and antioxidant profile of coriander plants under drought stress.