The Effects of Microplastic and Copper Treatments on the Number of Leaves, Stem, and Root Diameters in Tomato and Kale

Microplastics and heavy metals, which originated from irrigation water, fertilizers, pesticides, vehicles, and agricultural processes such as cover material treatments, are significant pollutants in agricultural ecosystems. Their harmful effects pose a threat to the health of organisms and ecosystems. This study aimed to determine the effects of microplastic and copper treatments on the number of leaves stem and root diameter in tomato Lycopersicum esculentum L.) and kale (Brassica oleraceae L. var. acephala DC.) plants. Microplastics were obtained by cutting agricultural mulch, used as a cover material, into small pieces (2.5 mm-4 mm) using scissors. Twelve experimental sets were created using microplastic concentrations of 0%, 0.5%, 1.5%, and 2.5%, along with copper sulphate (CuSO₄) at concentrations of 100 ppm and 500 ppm. The number of leaves, the stem and root diameters of the plants were measured. While the number of leaves, stem and root diameters in tomato plants, as well as the stem and root diameters in kale plants, did not significantly vary with microplastic and copper (Cu) treatments, significant differences were observed in the number of leaves in kale plants. The maximum and minimum leaf numbers were observed in the control group and the experimental set where 500 ppm CuSO₄ + 0.5% microplastic was applied, respectively. Different results emerged when microplastics and Cu were applied separately and together. These findings highlight the need for future studies that explore the long-term effects of microplastics and heavy metals on various plant species under different environmental conditions and using multiple physiological and biochemical parameters.