The Dissection Staining and Mounting of Styles in the Study of Pollen-Tube Distribution

Abstract

The methods here outlined, given in general in previous publications, are summarized with special reference to Datura styles. plstils, artificially pollinated and kept at 18-22[degree] C., are slit along 2 sides, scalded 1/2-2 min. in water at 70-75[degree] C, and killed by immersing several hours in 50% alcohol containing 6% formalin. Within 12 hours of killing, they are dissected with needles and forceps under a wide-field binocular microscope, removing the cortex from style and stigma. The strand of conducting tissue thus separated is stained within 24 hours of dissection in a watch-glass containing a mixture of 8 parts 1% aqueous acid fuchsin and 2 parts 1% aqueous or alcoholic light green. Staining requires 3-6 hours, and may be continued over night if stain is not too concentrated. The strand of tissue is cleared several hours or overnight in 80% lactic acid, carefully spread out on a slide, and mounted in lactic acid. After a few days the preparations are sealed around the edges of the cover-glasses with damar in xylol or paraffin which has gum mastic added to it.