Photosynthesis disrupted

Tiny plastic particles end up in trees

Tiny plastic particles reach the leaves and needles of trees via the roots. In this way, they disrupt photosynthesis, as an experiment by the Swiss Federal Institute of Technology (ETH) in Zurich shows.

The research team grew two hundred young trees, half wild service trees and half spruce trees. They placed their roots in water that had been enriched with nutrients instead of in the soil. They then added different concentrations of tiny plastic particles, known as nanoplastics, to the water.

After just a few weeks, the researchers discovered one to two milligrams of nanoplastics per gram of plant material in the roots. In the stem and in the leaves and needles, it was around ten to a hundred times less.

No influence on growth
Measurements showed that the effectiveness of photosynthesis in the service tree fell by a third within two weeks and by a tenth in the spruce within four weeks. However, the plastic particles had no effect on growth. According to the researchers, however, this could be due to the fact that the study was only conducted over a short period of time.

Our study should not give the impression that trees could die as a result of nanoplastics.

Wissenschaftlerin Denise Mitrano

"Our study is not intended to give the impression that trees could die as a result of nanoplastics," said scientist Denise Mitrano. However, the plastic could be an additional stress factor. The fact that some of the energy from sunlight is no longer used for photosynthesis is a typical stress reaction of trees. Instead, the energy is then dissipated as heat.