Comparative Study on Vascular Bundle Morphological Characteristics of Parts of Branches, Culms, and Rhizomes of Oligostachyum sulcatum

This study presents a comprehensive analysis of the vascular bundle morphology, tangential and radial diameters, and distribution frequency of different parts of Oligostachyum sulcatum, elucidating their structural and functional significance. Electron microscopy images revealed distinct vascular bundle characteristics in the different parts, including the vascular bundles in both parts of the rhizomes, the middle parts of the internodes, and the middle and inner parts of the branches, which were semi-open. The vascular bundles in the outer parts of both internodes and branches were semi-differentiated and undifferentiated. The vascular bundles in the inner parts of internodes were open. Statistical analysis showed significant variations in tangential and radial diameters among these parts, reflecting their diverse mechanical and physiological functions. The internodes exhibited the largest tangential and radial diameters, suggesting a critical role in mechanical support. In contrast, the branches had the smallest diameter, indicating that vascular bundle differentiation is influenced by growth conditions. The vascular bundle frequency was the highest in branches and the lowest in inside-sticks. This study provides theoretical references for the adaptive strategies and growth regulation mechanisms of O. sulcatum.