Multicellular plants depend for their integrity on effective adhesion between their component cells. This adhesion depends upon various cross-links; ionic, covalent or weak interactions between the macromolecules of the adjacent cell walls. In sugar-beet (Beta vulgaris L. Aztec) root parenchyma, cell-cell adhesion is disrupted by successive extractions with a calcium-chelating agent (imidazole) and a de-esterifying agent (sodium carbonate) but not by the calciumchelating agent or the de-esterifying agent alone. Cell-cell adhesion in sugarbeet parenchyma thus depends upon both ester and Ca 2þ cross-linked polymers. Pectic polysaccharides are removed by these treatments. Both parallel-electron energy-loss spectroscopy (PEELS) and Image-EELS show that calcium-binding sites are removed from the wall by imidazole. Using a monoclonal antibody that recognizes a relatively unesterified epitope of homogalacturonan, JIM 5, we show that a subset of JIM 5-reactive antigens remain in the middle lamella after Ca 2þ chelation and that this subset is removed by cold (4 C) Na 2 CO 3 -induced breakage of ester bonds. Fourier transform infrared, nuclear magnetic resonance, and spectrophotometric assays show that methyl and feruloyl esters are removed from the wall by Na 2 CO 3 but acetyl esters remain. Sodium carbonate extraction at 20 C removes cell wall autofluorescence and most of the feruloylated moieties from the wall. We propose that the chelator-resistant subset of ester-linked JIM 5-reactive pectins are important for cell-cell adhesion.