Atypical Growth, Abnormal Mitosis, Polyploidy and Chromosome Fragmentation Induced by Hexachlorocyclohexane

Abstract

THE best insecticides and fungicides will be those which kill the plant parasites without affecting the plant organism. In fact, they all affect the host plant more or less in various ways and degrees^1–4. A series of fungicides and insecticides may have very similar effects on the plant organisms. Ethyl-mercury-chloride (CH₃CH₂HgCl), which is the active substance (2 per cent) of the fungicide ‘Granosan', induces atypical growth, abnormal mitosis and polyploidy^3,4, reminding one of the effect of colchicine and acenaphthene^5,6. A similar and very strong effect of this kind is produced by hexachlorocyclo—hexane—another chlor-organic compound—which is the active substance of a series of very effective insecticides, recently recommended under various names. The insecticides ‘Agrocides' (7, 3, etc.), for example, the active substance of which is the gamma isomer of 1,2,3,4,5,6-hexachlorocyclohexane (‘Gammexane'), induce atypical growth, suppressing the development of the roots, stems and coleoptyles of gramineous plants, producing very striking thickening of these organs, especially of the growing points (root tips and coleoptyles).