The association of chromosomal abnormalities with malignant disease in vivo has been demonstrated by many investigators (see Porter et al. 1969). In vitro studies with lung tissues obtained from human fetus and young kittens (Na kanishi et al. 1959, Awa et al. 1961, mouse lung fragments (Bouchard and May 1960) and the KB line of mammalian cells in culture (Thayer and Kensler 1964) have indicated that cigarette smoke fractions have definite cytologic influences.Quantitative evaluation of such effects should provide information which may be important to health related research on tobacco.It seems obvious that experimentation with plants is faster and easier than the standard mouse skin bioassay which is commonly employed in assessing the biolo gical effects of tobacco smoke fractions and their components. The present investi gation was, therefore, conducted to ascertain the influence of water-soluble extract of tobacco smoke condensate (TSC) on the mitotic process in young roots obtained from onion bulbs. An attempt was made to investigate the feasibility of utilizing plant tissues for a rapid bioassay to detect the cytological effects caused by TSC. Material and methodsCommercially available bulbs of onion (Allium cepa) were utilized in the pre sent study. To obtain the roots, several bulbs were placed with their basal side facing downwards over small jars containing 60ml of glass-distilled water. The water in the jars was replaced at 24-hour intervals. After about 72hours, when the roots had emerged from the bulbs and were about one inch in length, the water was replaced by known concentrations of water-soluble extract of tobacco smoke con densate (TSC).

Floating plants of Wolffiella floridana produced turions in modified Hutner's medium containing 3 %sucrose. This is the first report on the induction of turions in the genus Wolffiella.

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