Suberized Cell Walls of Cork from Cork Oak Differ from Other Species

Abstract

AbstractPlants have suberized cells that act as protective interfaces with the environment or between different plant tissues. A lamellar structure of alternating dark and light bands has been found upon transmission electron microscopy (TEM) observation of cork cells and considered a typical feature of the suberized secondary wall. We observed cork cells from periderms ofQuercus suber,Quercus cerris, Solanum tuberosum, andCalotropis proceraby TEM after uranyl acetate and lead citrate staining. A lamellated structure was observed inS. tuberosumandC. procerabut not inQ. suberandQ. cerriswhere the suberized cell wall showed a predominantly hyaline aspect with only a dark dotted staining. Removal of suberin fromQ. subercells left a thinner secondary wall that lost the translucent aspect. We hypothesize that the species' specific chemical composition of suberin will result in different three-dimensional macromolecular development and in a different spatial location of lignin and other aromatics. A lamellated ultrastructure is therefore not a general feature of suberized cells.