Effects of cadmium on physiological responses of some plants

Abstract

This study investigated the physiological responses of two vegetable species, Kangkong (Ipomoea aquatica Forsk.) and Chinese Kale (Brassica oleracea L. cv. Group Chinese Kale), together with two weed species, False daisy (Eclipta prostrata L.) and Swollen finger grass (Chloris barbata Sw.) under Cd stress. These plants were exposed to 5 and 20 ppm Cd-containing solution with different exposure time. Proline accumulation, chlorophyll contents, Relative Water Content (RWC) and plant growth were determined against Cd accumulation both in roots and in shoots. The results have shown that proline is accumulated in Cd-stressed plants. However, the findings imply that proline accumulation is not an effective indicator of Cd stress. Unlike proline, chlorophyll contents, RWC and plant growth are adversely affected by Cd. Strong correlation (p≤0.01) between root and shoot Cd content were observed. As for the responses of each species, it was evident that Chinese Kale was the greatest Cd accumulator as well as the most tolerant species.