Figure 2. Effect of different concentrations of Cd on chlorophyll content (Chl) and photosystem II efficiency of barley (Hordeum vulgare L.) primary leaves. Plants were grown hydroponically in Murashige–Skoog medium for 10 d and exposed for 48 h to different concentrations of Cd. Each data point represents the mean value of 10 measurements (n = 10 different plants from two independent growth experiments). Error bars indicate the standard deviation (± SE).