Variations in leaf stomatal density and distribution of 53 vine species in Japan

To determine variations in stomatal density and distribution in individual leaves of vine species with different growth/life forms and different habitat types, we quantified and compared leaf-area-based stomatal density, epidermal cell density and stomatal index (percentage of stoma on the epidermis to the total cell number, including epidermal and stomatal cells on the epidermis) of 53 species comprising 19 woody species (lianas) and 34 herbaceous vines growing in Japan. We counted the numbers of stomata on both the adaxial and abaxial leaf surfaces using a light microscope. Stomatal density and distribution on the leaf surfaces varied greatly among species. Most of the creeping herbaceous species had stomata on both the adaxial and abaxial leaf surfaces (amphistomatous); however, lianas had no stomata on the adaxial leaf surface. Species from coastal (probably drier) habitats had greater adaxial to abaxial ratios of stomatal density and stomatal indices compared with species from inland habitats. A positive correlation between stomatal density and epidermal cell density was found on the abaxial/adaxial leaf surfaces of the examined species. This suggests that there is a developmental similarity among vine species in which stomata are developed with differentiation of epidermal cells on the leaf surface. Thus, leaf stomatal density and distribution appear to vary among species with different growth/life forms from different habitats under a developmental constraint of leaf surface in vine plants in Japan.