Anatomical Comparison of Roots, Leaves, and Stomata of Rhizophora stylosa Griff. under Various Salinity Levels

This study compares the root, leaf, and stomata anatomy of Rhizophora stylosa Griff. under various salinity levels and identifies anatomical parameters as indicators of salinity change. The experiment lasted for three months using a Completely Randomized Design (CRD) with five salinity treatments (15, 20, 25, 30, and 35 ppt), and three replications. The parameters observed included root structure (hypodermis and cortex thickness, density, and aerenchyma area), leaf anatomy (total thickness, hypodermis and palisade layers), and stomata characteristics (size, pore width, and density). Data were analyzed using ANOVA followed by DMRT. The results of the study show clear anatomical differences between low and high salinity levels. The most prominent adaptations occur at medium salinity levels (25–30 ppt), which are characterized by a thicker hypodermis layer, wider aerenchyma spaces, and larger stomata pores. These structural modifications indicate physiological strategies for maintaining water balance and reducing osmotic stress. These findings suggest that specific root, leaf, and stomata characteristics may serve as early biological indicators of salinity changes in coastal ecosystems. By providing anatomical references for assessing mangrove tolerance, this study contributes to an evidence-based approach for monitoring resilience and guiding conservation actions in the face of climate change-induced salinity increases.