Morphological and anatomical changes of Phragmites australis Cav. due to the uptake and accumulation of heavy metals from polluted soils

摘要

The effect of strong chemical contamination of soils on the growth and structure of reed (Phragmites australis Cav.) roots and stems has been investigated. Soils and plants on monitoring plots in the zone of industrial sewage tanks and sludge reservoirs in the city of Kamensk-Shakhtinskii (southern Russia) were studied. Polyelement pollution of soils on the studied monitoring plots was revealed, with exceedances of Clarkes in hundreds of times for Zn and Cd, in tens of times for Pb, and in several times for Cu, Ni, Cr, and Mn. An ecological-geochemical estimation revealed an extremely hazardous level of soil contamination HMs in total. It is shown that the high level of soil contamination decelerates the ontogenetic development of plants and decreases their morphometric parameters. Electron-microscopic study of plants revealed changes in the ultrastructure of cell membranes, as well as the main cytoplasmic organelles of root and stem cells (mitochondria, plastids, etc.). It is suggested that the revealed structural changes in epidermis and mesoderm under the impact of metals hamper the radial migration of fluid in the root from the peripheral parts. These changes are one of the reasons for the decrease in the level of nutrient uptake and translocation from roots to shoots.