High temperatures increase the uptake of nanoplastics by plants. This news comes from a study by the University of Pisa published in the journal Plant Physiology and Biochemistry, which analysed for the first time the amplifying effect of climate change on nanoplastic pollution.
The research was led by the Botanical Group of Professor Monica Ruffini Castiglione, and the Plant Physiology Group of Dr. Carmelina Spanò, in collaboration with her colleagues Stefania Bottega and Debora Fontanini. The experiments, carried out in the laboratories of the University of Pisa, used Azolla filiculoides Lam. as a model plant, a small floating water fern with thin roots that absorb the substances dissolved in water. Polystyrene nanoplastics, among the most common and widespread plastics used to make disposable cutlery and plates, packaging, take-away containers and seed trays for horticulture and floriculture, were used as pollutants.
Research group (from left to right: Prof. Monica Ruffini Castiglione, Dr. Carmelina Spanò, Dr. Debora Fontanini, Dr. Stefania Bottega).
The data showed that at 35°C the presence of nanoplastics in the plant increased significantly compared to the optimal situation at 25°C. This leads to deterioration of photosynthetic parameters and increased oxidative stress and toxicity in plants. The use of fluorescent nanoplastics also enabled researchers to accurately monitor their uptake and distribution in plant tissues and organs.
“The increased uptake of nanoplastics by plants at high temperatures raises concerns about the possible impact on crops of agronomic interest, with potentially significant implications for the inclusion of these substances into the food chain,” say Monica Ruffini Castiglione and Carmelina Spanò.
“Our study,” continues Ruffini Castiglione, “highlights that climate change doesn’t just amplify the negative effects of plastic waste, it can also create new dangerous synergies between environmental factors and pollutants, exacerbating existing ecological challenges. This must raise our awareness and lead to greater commitment to more sustainable behaviour, such as reducing the use of single-use plastic items.”
Azolla filiculoides in its natural habitat (on the left) and under laboratory conditions during treatment with nanoplastics at high temperature (on the right).
The researchers of the Botanical and Plant Physiology Groups involved in this study have been working for years on the responses of model and agronomically significant metal-accumulating plants, including plants in nanometric form and plants for emerging contaminants, such as micro- and nanoplastics. The interest stems from the awareness that plants are highly sensitive organisms, but at the same time resilient to environmental stress. This dual nature makes them ideal models for studying the impact of pollutants on living organisms, particularly in relation to climate change. The pioneering research carried out by the group, in collaboration with IBBA CNR and the University of Siena, has studied the interactions between plants and nanomaterials demonstrating, for the first time, the uptake and translocation of plastic nanomaterials in plant cells at the ultra-structural level.