Accumulation and distribution of heavy metal cadmium in sweet sorghum

Abstract

Many species of plants have been studied, as well as applied for cleansing the environment. Previous research has concluded that sorghum plants are highly tolerant to metal pollution and capable of reaching high biomass values in the presence of metals. However, the distribution of heavy metals in plant’s parts has not been adequately studied. In this study, two varieties of sweet sorghum (Keller and E-Tian) were grown with 5 levels (0, 5, 10, 25 and 50 ppm) of cadmium (Cd) in order to investigate the accumulation of Cd in plant parts at the hard dough stage. The results clearly showed the absence of Cd in the seeds of the above plants. There was the presence of Cd at the second and fifth leaf when the level of Cd reached 25 - 50 ppm. There was a great correlation coefficient between Cd and the position of the internodes, namely 0.86, 0.96, 0.99, 0.98 with KE, and 0.86, 0.92, 0.94, 0.94 with ET at 5, 10, 25 and 50 ppm Cd (P < 0.01), respectively. The greater the internodes, the lower the accumulation of Cd. The aforementioned plants recorded the high accumulation of Cd in their roots, peaking at 23.27 μg/g (dried weight, dw) in Keller and 21.69 μg/g in E-Tian. Based on these results, it is concluded that the distribution of Cd in the studied sweet sorghum can be arranged in the following order: > stem > old leaves > young leaves