Biological Significance of Changes in Stomatal Density and Stomatal Index of Aloe Species

Stomatal Index of Aloe Species

Abstract

Background: Aloe is a genus containing over 500 species of flowering succulent plants with enormous medicinal potential. Stomatal density and index vary greatly in the different species of this genus.

Objective: Aloe species were collected from the new botanical garden, University of Agriculture, Faisalabad. The size of stomata, the size of epidermal cells, the number of epidermal cells, and the number of stomata per ocular were measured to evaluate the anatomical changes in Aloe species.

Methodology: The experiment was conducted to explore stomata modifications in upper and lower leaf lamina of different Aloe species that are A. vera, A. karabergensis, A. striata, A. spinosissima, A. pachygaster, A. microstigma, A. hemingii, A. globuligemma, A. eru and A. conifera in Nov, Dec and Jan.

Results: Significant interspecific variation was observed in both stomatal index and stomatal density among the studied Aloe species, including A. vera, A. pachygaster, A. eru, A. striata, A. karabergensis, A. hemingii, A. conifera, A. microstigma, and A. globuligemma. Among these, A. pachygaster exhibited the highest stomatal density, whereas A. microstigma demonstrated the lowest.

Analysis of epidermal characteristics revealed that A. hemingii had the greatest number of epidermal cells, while A. microstigma had the fewest. Furthermore, stomatal size was markedly larger in A. pachygaster and A. striata, whereas reduced stomatal size was observed in A. vera and A. conifera across both adaxial and abaxial surfaces. These findings suggest species-specific adaptive responses likely linked to ecological or physiological traits, offering insights into taxonomic differentiation and potential drought resilience mechanisms in Aloe species.

Conclusion: Overall results showed great variations in all parameters in different Aloe species. The information obtained from this study can be used to assess the photosynthetic performance and dry matter yield of these species.