Scientists have discovered that zinc oxide nanoparticles derived from cassava peels can significantly boost tomato growth and drought resistance.
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A new study published in Plant Nano Biology found that zinc oxide nanoparticles (ZnO NPs) improved the growth and stress tolerance of tomato plants (Solanum lycopersicum L.) under water-limited conditions. The nanoparticles, synthesized using cassava peel extract, demonstrate the potential of nanotechnology in less explored fields, such as agriculture.
Agritech is looking to nano-scale science for solutions to long-standing challenges, such as inefficient nutrient use and climate-related stress. Among the most studied materials are ZnO NPs, because of their ability to enhance root development, boost nutrient uptake, and improve drought tolerance in crops.
What makes ZnO NPs particularly attractive is their dual functionality. They can stimulate plant growth and also appear to trigger internal defense mechanisms, helping plants manage oxidative stress, a common side effect of drought conditions. Further, their antimicrobial properties may offer protection against soil-borne pathogens, reducing the need for chemical pesticides.
Cassava Peels Turned Crop Booster
In this study, researchers at Lagos State University used cassava peel extract as a natural reducing and stabilizing agent to produce the ZnO NPs through a green synthesis. Starting with a waste material aligns with circular economy principles, recycling an unused output material into a valuable input.
The nanoparticles were synthesized by dispersing ZnO in cassava peel extract and HCl, followed by a reduction. Successful production of the NPs was assessed using scanning electron microscopy (SEM) and X-ray diffraction (XRD) to confirm their size and structure.
Once characterized, the team monitored the effects of different concentrations of ZnO NPs (1.0, 2.0, 3.0, and 4.0 g/L) on tomato seedlings, comparing them to untreated controls.
Over eight weeks, key growth indicators such as plant height, leaf number, leaf area, and total biomass were recorded. Physiological stress markers, including reactive oxygen species (ROS), malondialdehyde (MDA), and hydrogen peroxide (H2O2), were measured, alongside antioxidant enzyme activity for catalase (CAT), superoxide dismutase (SOD), and ascorbate peroxidase (APX).
Sharper Growth, Lower Stress
After eight weeks of growth, the plants treated with ZnONPs, particularly those treated with the highest concentration at 4.0 g/L, showed substantial improvements.
On average, treated plants grew almost half a meter taller (48.33 cm), produced more leaves (18.67), and had a larger leaf area (82.33 cm2). The biomass of ZnO NP treated plants increased by 20 % compared to untreated plants, suggesting enhanced nutrient uptake and metabolic activity.
The researchers also found that oxidative stress decreased. Key indicators of cellular damage, MDA and H2O2, were significantly lower in treated plants. Meanwhile, antioxidant enzyme activity was notably higher, with CAT, SOD, and APX levels rising by 30 %, 25 %, and 35 % respectively.
These results indicate that ZnO NPs not only promote physical growth but also activate the plant’s internal stress response systems, making them better equipped to handle drought conditions.
A Sustainable Path for Farmers
The implications for sustainable agriculture are significant. By improving plant resilience and reducing the need for synthetic fertilizers and pesticides, ZnO NPs offer a practical solution for farmers operating in water-scarce environments.
The green synthesis method using cassava waste also presents an affordable, eco-friendly alternative to conventional nanoparticle production, potentially lowering costs and supporting waste-to-resource initiatives in agricultural communities.
While the study’s findings are promising, the authors recommend further research to fine-tune application methods and evaluate long-term effects on soil health and crop yields. Larger-scale field trials will be essential to confirm the nanoparticles’ performance outside of controlled environments.
Understanding the precise biochemical mechanisms behind ZnO NPs’ effects on plant physiology could also open doors to even more targeted agricultural applications, but further research into the larger effects of nanoparticle-treated plants needs to be done before wide-spread uptake is possible.
Journal Reference
Ojewumi, A, W., et al. (2025). Growth and production of water-stress indicators modified by zinc oxide nanoparticles as nanofertilizers under water-regulated conditions on tomatoes (Solanum lycopersicum L.). Plant Nano Biology, 13 (100168). DOI: 10.1016/j.plana.2025.100168, https://www.sciencedirect.com/science/article/pii/S277311112500035X