Accumulation of heavy metals in the strawberry plants grown in conditions of anthropogenic pollution

In case the large strawberry plantations and the plots of amateur gardeners are located in the areas, influenced by industrial centers, the risk of soil and air pollution with heavy metals is high, and the background values of Cu, Zn and Pb, for instance, can be 4-55 times increased. In plant there are physiological barriers between the root and the stem, the stem and the leaf, and the stem and reproductive organs, which prevent penetration of the toxicants into fruits. During 2006-2008 we evaluated the accumulation of Pb, Ni, Zn, Fe, and Cu in roots, rhizomes, petioles, leaves and fruits in four strawberry Fragaria ½ ananassa (Duchesne ex Weston) varieties, grown on the light gray forest soil under multielement anthropogenic pollution in Orlovskaya Province. The accumulation of each element was shown to be specific, depending on its physiological effect and chemical properties, and on the anthropogenic load. Significant differences among the varieties were also observed. In Rubinovii kulon, Mamochka, and Bylinnaya varieties the Pb content in leaves was higher than in the roots, probably due to extra foliar absorption from air. In Bogema variety the Pb accumulation gradually decreased from the roots to rhizomes, then to leaves and finally to fruits. Considerable Ni content in the roots was indicated only in Mamochka variety. In other tested varieties the Ni accumulation in fruits was significantly higher than in the underground organs. Zn and Fe distribution among strawberry plant organs was specified by the varietal genetic features. Zn was not accumulated in the vegetative organs of Rubinovii kulon and Mamochka plants. Conversely, the high accumulation of Zn was found in the roots of Bogema plants and in the rhizomes of Bylinnaya plants. In Rubinovii kulon, Mamochka and Bogema plants the Fe accumulation was mainly detected in the roots and in the berries, whereas in Bylinnaya plants this element was mainly concentrated in the rhizomes and petioles. The least significant difference for factor A (strawberry varieties), factor B (plant organs) and their combination (AB) makes for Pb 0.24, 0.27, and 0.53, respectively; for Ni - 0.04, 0.05, and 0.10, respectively; for Zn - 0.24, 0.27, and 0.53, respectively; for Fe - 0.79, 0.89, and 1.77, respectively; for Cu - 0.47, 0.52, and 1.05, respectively. An unequal accumulation of toxicants among the varieties, which were not bred with a view to low heavy metal penetration under soil and air pollution, shows that the ecological risk of the heavy metal accumulation in fruits could be decreased by purposeful choosing varieties for cultivation with respect to their physiological features.