Abstract
Root-tips and leaf tips of different plants were kept for 1-2 hr at 12-14° C in saturated aqueous isopsoralene solution and stained in a mixture of 1 N HCl and 2% acetoorcein (1:9 by volume) by heating for 3-4 sec over a flame. They were then squashed in 1% aceto-orcein under a cover glass, the excess being blotted and the cover sealed. Preparations could be kept for about 15 days. A good chromosome morphology was secured. Isopsoralene was found to be suitable in cases where other coumarin derivatives as well as paradichloro-benzene failed to yield suitable results.