THE ROLE OF PARTICULAR PERICYCLE CELLS IN APOPLASTIC TRANSPORT IN ROOT-MERISTEMS OF BARLEY

Two apoplastic markers, lanthanum and Fluorescent Brightener 28, were used to trace an apoplastic pathway in the root apex of barley seedlings (Hordeum vulgare L. cv. California Mariout). Light and electron microscopy revealed that the markers accumulated in the walls of pericycle cells immediately external to each protophloem sieve element. The presence of lanthanum was confirmed by X-ray micro-analysis of fully-hydrated, bulk-frozen samples. These results suggest that the apoplastic pathway for ions and water moving between the cortex and stele in the meristematic region is largely confined to the walls of particular cells in the pericycle layer. © 1990, Gustav Fischer Verlag, Stuttgart. All rights reserved.