A SQUASH PREPARATION METHOD FOR ROOT-MERISTEM FIELD STUDIES

We present a field method for squash preparation of root apical merist em that does not require dry ice for cell adhesion to a slide. The met hod is based on the use of a weak gelatin solution as a stabilizing ag ent to prevent cell loss. Alcian blue 8GX was used as a counterstain f or better recognition of cell shapes. Root meristems of Sonoran Desert succulents were used to illustrate the method. Fixed root tips were s tained by Feulgen and squashes were prepared in a 1:2 mixture of solut ion A (45% acetic acid) and solution B (3:1 mixture of 0.5% gelatin in water:0.02% of alcian blue 8GX in 45% acetic acid). After squashing, the material was lightly dried for 5-6 min, then dehydrated and mounte d in Canada balsam. Our method permits observation of chromosomes, rec ognition of meristematic and nonmeristematic cells, and estimation of mitotic indices and thus recognition of growing, dormant, and dead roo ts. The method can be used for estimation of cell division cycle time by colchicine and other methods where squash preparation is required.