TRADESCANTIA STAMEN HAIR MUTATION BIOASSAY

The Tradescantia stamen hair mutation (Trad-SH) assay (clone 4430) was evaluated for its efficiency and reliability as a screen for mutagens in an IPCS collaborative study on plant systems. Four coded chemicals , i.e. azidoglycerol (AG, 3-azido-1,2-propanediol), N-methyl-N-nitroso urea (MNU), sodium azide (NaN3) and maleic hydrazide (MH) were distrib uted by the Radian Corporation to the five laboratories in five differ ent countries for testing mutagenicity. Pink mutations were scored bet ween the 7th and 14th day according to a standard protocol. Test resul ts from the five individual laboratories were analyzed and compared af ter decoding. One out of the two laboratories that conducted tests on AG demonstrated that AG is a mutagen with genetically effective doses ranging from 50 to 100 mu g/ml. MH yielded positive responses in all l aboratories but no linear dose-response pattern was observed. The effe ctive dose range for MH was between 1 and 45 mu g/ml. The mutagenicity of MNU was reported by five laboratories in the dose range between 10 and 80 mu g/ml. NaN3, which exhibited a relatively high degree of tox icity, elicited a positive mutagenic response in three of the five lab oratories in which it was tested. As with MNU the effective dose for N aN3 ranged between 3 and 80 mu g/ml. The results from the current stud y substantiate the Trad-SH assay as a reliable system for screening ch emicals for their potential mutagenic effects. Although the study was carried out exclusively under laboratory conditions, a survey of the c urrent literature would indicate that the Trad-SH assay could be an ef fective in situ monitor of gaseous, liquid, and radioactive pollutants as well.