Diversity in Stomata Morphology among Cultivated Blueberry Genotypes and Its Influence on Irradiance Response Dynamics

Abstract

Stomata are pores on the leaf epidermis that control gas exchange between leaves and the atmosphere. Stomata differ in shape, size, and number among and within plant species. Stomata morphology has physiological consequences for some plant species. We investigated stomata morphology of different blueberry (Vaccinium spp.) genotypes and its influence on the speed of response to a change in irradiance. Understanding how these traits affect gas exchange can inform breeding programs and management practices to enhance agricultural productivity and resilience. Thirty-seven blueberry genotypes of southern highbush blueberry (SHB), northern highbush blueberry, and rabbiteye blueberry grown in seven different locations in North America were evaluated. Significant diversity in stomata area (Sa) and stomata density (Sd) were observed among the studied genotypes. Changes in Sa and Sd were not compensatory. During a follow-up study, the effects of Sa and Sd on the temporal response of stomatal conductance (gs) to changes in irradiance were studied. The stomatal speed of response of the tested SHB genotypes was significantly affected by Sd, but not by Sa. Additionally, significant differences in minimum gs were documented. Overall, this study provides foundational information about the stomatal biology of a globally important fruit crop.