The impact of stone quarries on the anatomy, morphology, and biochemistry of Urtica dioica L. (Urticaceae) in two natural protected areas in southwestern Romania

Abstract

Plant species react differently to pollution, having some ability to adapt through compensation. This study presents the case of Urtica dioica L. (nettle), a plant with overgrowing features in contemporary landscapes. We studied the morphological, anatomical, and biochemical changes in nettle leaves. Four samples were collected: two from natural protected sites in southwestern Romania, from sites without air pollution, and two from stone quarries situated in the same natural protected areas as the unpolluted sites: the Meri quarry (in the Jiu Gorge National Park - JGNP) and the Eşelnița quarry (in the Iron Gates Natural Park - IGNP). We identified necrosis, lesions, insects, and insect bites on the leaves collected from the polluted sites in the morphological and micromorphological study of leaves. These changes were also observed in the leaf structure. From a biochemical perspective, we observed a quantitative increase in assimilating pigments, which can be interpreted as a compensatory response to dust pollution. On the other hand, we did not record an increase in phenols, flavonoids, or antioxidant activity in these leaves. However, we found a drastic decrease in the samples from the polluted sites compared to those without dust pollution.