Microplastics are pervasive and a problem for all life. Kanold and colleagues examined six plant species to see how they coped with microplastics in the soil, looking at their roots. Surprisingly, they found that some plants grew more biomass with microplastics in the soil. Their findings will help research into how plastic pollution affects plant health.
The team used a mix of different microplastic types and shapes to mimic real-world pollution. They then grew the plants in with no microplastics, low levels (0.1%), or high levels (1%). They chose plants with different root strategies. Onion, chive and leek were chosen to represent resource conservation root traits. Tomato, eggplant and pepper represented plants with resource acquisitive root traits.
Kanold and colleagues found that high microplastic additions resulted in significantly higher total biomass within eggplant, tomato and leek, compared to the control treatments. They also found that while microplastics didn’t significantly change average root characteristics, they did increase variation in root growth within each plant species. They also found that high levels of microplastics reduced colonisation by beneficial fungus on tomato plant roots.
Kanold and colleagues say this is one of the first realistic microplastic experiments on multiple plant species. They argue that previous research used single plastic types or unrealistically high amounts of microplastics. While their results suggest some plants might tolerate or even benefit from microplastics, they add that when combined with other stressors like climate change, microplastics could still harm plants.
Therefore, a critical question emerges: under real-world conditions, where plants face multiple stressors such as climate change, interspecies competition, invasion, herbivory, and disease, is there a tipping point beyond which these combined pressures exceed their capaticy to cope?
Kanold, E., Buchanan, S. W., Dunfield, K., & Antunes, P. M. (2024). Microplastic additions modulate intraspecific variability in root traits and mycorrhizal responses across root-life history strategies. Functional Ecology. https://doi.org/10.1111/1365-2435.14659 (OA)
