A common ingredient in sunscreen, zinc nanoparticles, may help protect rice plants from heat stress, a growing issue caused by climate change.
Zinc plays an important role in plant metabolism. Traditionally, zinc is added to soil or sprayed on plant leaves as a fertilizer, but this method is not always efficient. An alternative approach is to use zinc in the form of nanoparticles—tiny particles smaller than 100 nanometres—which can pass through the small pores on plant leaves and be absorbed by the plant.
Researchers have been investigating these nanoparticles as a way to deliver nutrients more effectively, aiming to boost crop yields while reducing the environmental impact of overusing fertilizers. Now, a team led by Xiangang Hu at Nankai University in China has tested the effects of zinc oxide nanoparticles on rice crops under heat stress.
The team grew rice plants in a greenhouse, exposing some to normal conditions and others to a simulated heat wave, where temperatures exceeded 37°C for six consecutive days. Some plants were treated with zinc nanoparticles, while others were not.
When harvested, the rice plants treated with zinc nanoparticles showed a 22.1% increase in grain yield compared to untreated plants. These plants also had higher levels of nutrients. The positive effects of zinc were also observed in normal conditions, with treated plants showing even greater yield differences than in heatwave conditions.
The researchers found that zinc nanoparticles improved plant performance by enhancing enzymes involved in photosynthesis and boosting antioxidants that protect plants from damage caused by harmful molecules known as reactive oxygen species (ROS).
Jason White, a researcher at the Connecticut Agricultural Experiment Station, noted that “nanoscale micronutrients have tremendous potential to increase the climate resilience of crops by helping plants fight the harmful effects of reactive oxygen species.”
Additionally, the rice plants treated with zinc nanoparticles maintained a more diverse range of microbes on their leaves, which could have further supported growth and resilience.
The researchers also tested zinc oxide nanoparticles on other crops like pumpkin and alfalfa, showing similar increases in yield. However, Hu emphasizes that more research is needed to confirm whether this approach could benefit other types of crops.
This study suggests that using zinc nanoparticles could be a promising method to help crops withstand extreme weather conditions, a growing challenge as climate change continues to affect global agriculture.
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