Localization of chemically induced chromosomal aberrations in three different karyotypes of Viciafaba

Abstract

Andersson, H. C. and Kihlman, B. A. 1987. Localization of chemically induced chromosomal aberrations in three different karyotypes of Vicia faba. — Hereditas 107:15–25. Lund, Sweden. ISSN 0018–0661. Received October 3, 1986 For the purpose of mapping the distribution of chromosomal aberrations. Rieger and Michaelis have divided the chromosomes of Viciafaba into segments, numbered 1–28. We have used this mapping system in a study of the localization of aberrations in segments nos. 2 (=nucleolar constriction) and 4 after treatments of root tips of Vicia faba with mitomycin C (MMC), maleic hydrazide (MH), hydroxyurea (HU) and 8-ethoxy-caffeine (EOC). Seedlings of three different karyotypes were used in these experiments. In all three karyotypes. the chromatid aberrations induced by MMC and MH were preferentially localized in segment 4. whereas a high frequency of those induced by HU and EOC were localized in segment 2. The types of aberration induced by HU and EOC in segment 2 differed. however. After treatments with HU, the aberrations were almost exclusively chromatid interchanges. whereas the majority of the aberrations induced by EOC in segment 2 were isochromatid breaks. Of the exchanges induced by EOC in segment 2, more than 50 were triradials. whereas less than 10 % of the exchanges induced by HU in segment 2 were of the triradial type.