MITOTIC DISTURBANCES CAUSED BY CHLORANIL

Abstract

IN THE COURSE of a cytological and cytochemical analysis of changes induced in meristematic tissues of various plants by alkaloids, phenols, and heterocyclic compounds, marked mitotic disturbances were observed in sections of untreated root tips of Vicia Jaba L. being used as controls. The root tips had been cut from seedlings germinated in a moist chamber at room temperature. From recent studies on the injurious action of certain herbicides, fungicides, and insecticides (Sass, 1937, 1938, 1951; Carey and McDonough, 1943; Ennis, 1948), it seemed possible that the mitotic disturbances observed in Vicia seedlings were due to treatment of the seeds with such agents before they reached this laboratory. At the time of purchase the seeds were coated with a fine, yellowish powder, and inquiry revealed that they had been dusted with a commercial fungicide whose active ingredient is chloranil (tetrachloro-p-benzoquinone). The study reported here was undertaken to determine the effect of this compound on mitotic processes. Since it was not pos-sible to purchase seeds of Vicia faba with assurance that they had not been inadvertently exposed to this or some other fungicide, root tips of onion (Allium cepa L.) were used in the experimeilts described. The effects of both this fungicide and chloranil (from Eastman Kodak Co.) were determined by cytological and cytochemical studies of sectioned tissues. The cvtochemical approach involved treatment with nucleases and subsequent staining in basic dyes or by the Feulgen reaction. Similar observations on sections of roots grown from the dusted Vicia seeds afforded material for a comparative study of the effect of the commercial preparation on mitotic processes in two different species of plants. MATERIALS AND METHODS.-The seeds of Vicia were germinated on moist filter paper in Petri dishes after thorough washing and removal of the seed coats. On the fourth day of growth the root tip and plumule were removed and fixed in acetic acidalcohol (1 part of glacial acetic acid and 3 parts of absolute alcohol). Fixation continued for 12 hr. The material was transferred to 70 per cent