The effects of heavy metals on the anatomical structures of Avicennia marina (Forssk.) Vierh

Anatomical changes observed in a mangrove plant, Avicenna marina, were studied with special reference to heavy metal pollution at Visakhapatnam Meghadrigedda creek area. The pollution in the region was very well reported to have been caused by the port activities and also by several major industries abutting the Meghadrigedda creek area. The concentrations of heavy metals, namely copper, chromium, cadmium, manganese, zinc, and lead, were determined using ICP-MS techniques. The heavy metal concentrations are more in sediments than in the native soils, whereas when focused on the role of mangroves, especially in Avicenna marina species, plants, exposed to higher concentrations, exhibited anatomical variations in the xylem of the stem and leaves also. The stem internal structure showed a xerophytic adaptation, with a thick cuticle, thick-walled cortex with an appearance as stone cells. The mainly noticeable characteristics are moist leaves, with expanded mesophyll area, thick cuticle with wax deposition shown on the epidermis. At lower concentrations, these changes did not exist. Bioconcentration factor (BCF) and translocation factor (TF) had been calculated to estimate the efficiency of a plant to accumulate heavy metals from sediment to its roots and translocate the heavy metals from its roots to its stems and leaves, in observed anatomical changes at higher concentrated area plants.