TY JOUR TI SPERMATOZOA POLYMORPHISM AND NUCLEOLUS MATERIAL CHANGES UNDER THE ZINC CHLORIDE INFLUENCE KW spermatozoon KW zinc chloride KW heavy metal KW influence KW nucleoli KW nucleus KW cell KW spermatogenic epithelium JO Bulletin of KSAU AU Vladimtseva, T.M. PY 2012 IS PB Krasnoyarsk State Agrarian University