Root-Tip Smears Following Fixation with Boiling Water

A convenient, quick method of preparing fresh root-tips for the detailed study of the critical stages of mitosis is presented. The cells of fresh-cut root-tips are killed and fixed instantaneously by immersion in boiling water. To effect maceration, the root-tips are transferred to a mixture of 95% ethyl alcohol and concentrated HCl. The root-tips are then smeared in a drop of aceto-carmine with glass instruments. Application of mineral oil makes the preparations permanent or semi-permanent. Characteristically, anaphasic chromosomes in the fresh materials thus prepared appear as structures composed of a swollen transparent matrix in which are embedded spiral interlocking chromonemata. Suggestions are offered as to the advantages and possibilities of the technic.