Extreme weather and pollution have increased the salt content in some soil, making growing conditions harsh for salt-sensitive crops like rice. Now, researchers reporting in ACS Nano detail a possible solution that doesn’t require genetic modification to make rice plants thrive in these conditions. In lab experiments, they determined that coating rice seedlings with magnesium-doped carbon dots—derived from durian peels—increased the seedlings’ antioxidant activity and photosynthesis, reducing the stress caused by salty soil.
To increase stress resistance in plants, the current state-of-the-art solution is gene editing. However, gene editing technologies can be cost-prohibitive, and some people are concerned about the health effects and safety of genetically modified foods.
One potential alternative to genetic modification is coating plant leaves with nanoscale carbon dots that counteract oxidative stress by mimicking the plant’s antioxidant enzymes. So, Longwei Jiang, Jianguo Zeng and colleagues designed a carbon dot using pulverized durian peel that could neutralize reactive oxygen species (ROS) and alleviate salt stress-induced damage in rice plants.
Durian peels are inedible and account for 70 to 85% of the fruit’s weight. The peel also contains a lot of carbon, making the discarded rind a good source for biomass-derived carbon dots. The researchers doped their durian-derived carbon dots with magnesium—an element essential for plant growth—and then sprayed them on rice seedlings planted in salt-free and salty soils.
The team found that seedlings treated with their dots contained lower levels of ROS and grew taller in salty soils than untreated seedlings. Furthermore, treated seedlings had activated plant defense and photosynthesis genes that weren’t activated in untreated seedlings.
The researchers caution that more information is needed to better understand how exactly the dots are triggering these cellular and genetic changes; more information is also needed about the treated plants’ impact on the environment and the humans and animals that consume them. However, the study concludes that carbon dots represent a potential strategy for enhancing plant salt tolerance and provide valuable insights for their agriculture applications.
