A squash preparation method for root meristem field studies.

We present a field method for squash preparation of root apical meristem that does not require dry ice for cell adhesion to a slide. The method is based on the use of a weak gelatin solution as a stabilizing agent to prevent cell loss. Alcian blue 8GX was used as a counterstain for better recognition of cell shapes. Root meristems of Sonoran Desert succulents were used to illustrate the method. Fixed root tips were stained by Feulgen and squashes were prepared in a 1:2 mixture of solution 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 mounted in Canada balsam. Our method permits observation of chromosomes, recognition of meristematic and nonmeristematic cells, and estimation of mitotic indices and thus recognition of growing, dormant, and dead roots. The method can be used for estimation of cell division cycle time by colchicine and other methods where squash preparation is required.