Micromorphological study of epidermis and stomata in selected species of Salvia in central Iran

The genus Salvia L. (Lamiaceae) is considered as one of the largest plant genera due to its global distribution and extensive morphological diversity. This research aimed to examine the micromorphological characteristics of the epidermis and stomata in 20 selected species of this genus. Plant samples examined using light microscopy (LM) and scanning electron microscopy (SEM). Quantitative characteristics, including stomatal count and dimension measurements, and qualitative features, such as the arrangement of epidermal cells and the positioning of guard cells, were analyzed. The results showed that, S. virgata and S. syriaca had the highest and lowest stomatal index, and S. viridis and S. officinalis had the longest and shortest stomata, respectively. Significant differences in the appearance of stomata and epidermal cells among the species were noted with stomata in some species being square-shaped. Epidermal cells in some species were ridged while in others were smooth; and all species exhibited diacytic stomatal types. This study demonstrated that, micromorphological characteristics of the epidermis and stomata are useful diagnostic tools for identifying and classifying Salvia species. The use of LM and SEM provided precise information for this purpose, contributing to the improvement of taxonimc methods and plant identification. The observed differences and similarities are likely due to ecological conditions and genetic variations, and understanding these relationships can aid in the development of more exact methods for classifying and identifying species in botanical studies.