Responses of stomata to changes in humidity

摘要

Large areas of the lower epidermis of full-grown leaves ofPolypodium vulgare(andValerianella locusta) are normally separated from the mesophyll by an extensive subepidermal airspace. Epidermal stripes were prepared for experiments to simulate these conditions in order to investigate stomatal reactions. They were placed with their inner surface in contact with an airspace of uniformly high humidity. The outer surface was treated with air of varying degrees of humidity. The stomatal reactions were observed by microscope and the opening of the guard cells determined photographically.