Structural and functional response to metal toxicity in aquatic Cyperus alopecuroides Rottb

Morpho-anatomical and physiological response of Cyperus alopecuroides Rottb. (Family Cyperaceae), occurring in industrial-polluted water near Sheikhupura, Pakistan, to metal (Ni and Cd) stress were examined. Two levels (30 and 60 mgL(-1)) of each of Ni and Cd were maintained during the experiment. Growth and development were severely affected by both metals, however, Cd was more toxic than Ni, although Ni was absorbed readily by the roots and its considerable amount was translocated to aerial plant parts due to its mobile nature. In contrast, high amount of Cd were retained in the roots. Specific root physio-anatomical modifications for Ni tolerance were found result from leaf turgor potential, high accumulation of organic osmolytes, enhanced sclerification, and aerenchyma formation, while leaves were more developed bulliform cells and stellate parenchyma. Cd tolerance was found to be related to accumulation of organic osmolytes, thick epidermis and endodermis, enhanced sclerification, and stellate cell formation in stem, and well developed bulliform cells in leaves. The structural and functional response of metal toxicity were very specific in C alopecuroides depending on the type of metal which enabled this species to survive successfully in metal-polluted wetlands. (C) 2014 Elsevier GmbH. All rights reserved.