The Occurrence of Silica in the Leaves of Magnolia grandiflora L.

Abstract

The glistening bodies observed at the foliar veinlet termini, epidermis and vein sheath in M. grandiflora L. contain silica. The silica was studied by light microscopy, transmission electron microscopy, scanning electron microscopy and energy dispersive X-ray microprobe analysis as isolated particles (phytoliths) and in sectioned leaves. The silica is amorphous and is composed of roughly spherical bodies (35-65 nm) that form in the lumen of terminal tracheids, vein sheath cells, epidermal cells and guard cells. Silica is also found as a layer exterior to the cell wall of epidermal cells and in the cuticle. In the leaf, silica deposition may function to strengthen the leaf, reduce transpiration and increase resistance to pathogens.