Plant materials were ground and digested with a mixture of HNO3/HClO4 (Zhao et al., 1994), and the major and trace elements in the digests were determined using inductively coupled plasma atomic emission spectrometry (ICP-AES, Perkin±Elmer, 3300 DV).
Plant materials were ground and digested with a mixtureof HNO3/HClO4 (Zhao et al., 1994), and the major andtrace elements in the digests were determined using inductivelycoupled plasma atomic emission spectrometry(ICP-AES, Perkin±Elmer, 3300 DV).