Author Affiliations +
Huiqin Ma, Sujian Pei
Department of Life Sciences, Hengshui University, Hengshui, Hebei 053000 P. R. China. E-mails: , , respectively. mhq008@yahoo.com peisujian@126.com
Mingsheng Zhu
College of Life Sciences, Hebei University, Baoding, Hebei 071002 P. R. China. E-mail: mingshengzhu@263.net