Methods for creating stomatal impressions directly onto archivable slides

Stomatal density has been shown to be a primary determinant of crop yield, water use efficiency, and limitation to CO2 assimilation rate. Widely used methods of assessing stomatal density sample relatively small regions of the leaf, are labor intensive, or do not yield stable archivable samples for revisiting samples. We describe several methods of producing such epidermal impressions that yield samples large enough to generate stomatal density maps across entire leaf surfaces.