An Improved Infiltration Series for Studying Stomatal Opening as Illustrated with Coffee

Abstract

Very satisfactory results have been obtained in estimation of the degree of stomatal opening of several plant species by using infiltration series prepared with Nujol mineral oil diluted with xylol, kerosene, n-dodecane, n-tetradecane, or Bayol-D. All of these materials, except Nujol, infiltrate the leaves when the stomata are only slightly open. Nujol does not penetrate even wide open stomata, except for plants with particularly large stomata. The results with coffee plants show that leaves exposed to direct sunlight decreased their stomatal aperture during periods of strong illumination in the middle of the day (more than about 8000 fc). 9 references, 2 figures.