A RAPID SQUASH TECHNIQUE FOR STEM AND ROOT TIPS

Abstract

A method of preparing permanent slides of stem and root tips for chromosomal studies is described. It involves the following procedure:1. Fix in Carnoy's fluid, 30 min.2. Macerate and hydrolyse at room temperature in a mixture of concentrated hydrochloric acid and 95% ethanol (1: 1) 5 to 10 min.3. Rinse as quickly as possible in two changes of water.4. Stain in leuco basic fuchsin, one hour (or longer).5. Transfer material to drop of 50% acetic acid on slide, cover, squash by tapping with a pencil, and, protecting cover glass with absorbent paper, apply pressure with finger. Allow to stand until drying begins under cover glass (about 10 min.).6. Remove cover glass, flood both cover and slide twice with 95% ethanol and three times with n-propyl acetate at about half-minute intervals, place drop of Canada-balsam–xylene on slide and replace cover glass.The method has proved satisfactory in over 20 species, mainly in Pinaceae.