Relations between phenotypic aberrations and loss of reproductive integrity in Tradescantia stamen hairs

Abstract

Cuttings of Tradescantia clone 02 bearing young inflorescences were irradiated with 0·43-MeV neutrons (0·163–24·4 rad). Others were irradiated with 250-kVp X-rays (11·5–432 rad). Stamen hairs were scored in opened flowers up to day 23 postirradiation for hair length (a hair “survivor” ≥ 12 cells long) and the type of somatic aberration or mutation within each hair. Distribution of numbers of cells per hair at various doses for both treatments, for the normal and aberrant hair types, were compared, and survival curves were constructed separately for normal and aberrant hairs. The distribution of hair lengths, and survival curves were used as criteria for measuring loss of reproductive integrity (LRI). Shorter hairs tend to occur in association with a phenotypic aberration, although aberrations can occur also in hairs of normal length. The results suggest that LRI is definitely associated with and possibly caused in part by the same event responsible for the presence of a phenotypic aberration. In aberrant stamen hairs, the surviving fraction is reduced by more than a factor of 2 following irradiation compared to that of normal hairs.