Chromosomal anomalies cannot account for growth rate reduction in ultrasonicated Vicia faba root meristems

Abstract

The possibility that root growth rate reduction following ultrasonication might be the result of loss of reproductive integrity in cells bearing ultrasound-induced chromosomal anomalies was considered. Root meristems of Vicia faba were ultrasonicated at a frequency of 2MHz and an intensity of 8 W/cm 2 for one minute. The surviving fraction of cells, calculated from root growth rate according to the model of Hall, Lajtha and Oliver (14) was 0·58. The weighted average yield of chromosomal-anomaly-bearing cells at the first post-sonication mitosis was 0·105. Thus, the number of cells with chromosomal anomalies is only 1 4 the number needed to account for the calculated cell surviving fraction. This result suggests that root growth rate reduction following ultrasonication may be due largely to effects of the sound field on elongating cells rather than to effects on meristematic cells.