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Plant cell walls provide essential functions in cell recognition, differentiation, adhesion and wound responses. Therefore, it is tempting to hypothesize that cell walls play a key role in grafting, but to date there are no quantitative studies targeting on cell wall changes during grafting. The aim of this work was to investigate the dynamics of pectic and hemicellulosic polysaccharides at the graft junctions in tomato homografts throughout the first 12 days after grafting. Cell wall fractionation, combined with ATR-FTIR spectroscopy and gas-chromatography, evidenced a marked increase in pectin content and a decrease in the degree of methyl-esterification of homogalacturonan in scion and rootstock throughout grafting. Also, recovery of tightly-bound hemicelluloses decreased at late times after grafting suggesting an increase of cross-linked hemicelluloses along grafting. In addition, immuno-dot assays revealed an increase in xyloglucan and arabinogalactan proteins in the first days after grafting, pointing to a presumed role in tissue adhesion-cohesion., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Inula viscosa (syn Dittrichia viscosa) (sticky fleabane) from the Asteraceae family, is well-known for its pharmacological activities. In this research, anatomical characterization of leaves and stems of Inula viscosa plants revealed a considerable heterogeneity in their cell walls. Cell walls were isolated separately from leaves and stems and subjected to sequential extractions with boiling water, oxalate ammonium, KOH and NaOH solutions. The four polysaccharide fractions obtained were comparatively analysed using gas chromatography-flame ionization detector (GC-FID) and Fourier Transform Infrared–Attenuated Total Reflectance (ATR-FTIR) spectroscopy. The findings showed that the polysaccharides were unevenly distributed in the two organs. ATR-FTIR data reflected a higher proportion of pectins in stems relative to leaves in both fractions. Pectic fractions (hot water soluble and oxalate soluble fractions) seemed to be mainly composed by homogalacturonan and rhamnogalacturonan, with a residual presence of inulin. Hemicellulose (KOH and NaOH) fractions, instead, were rich in xylans, and still contained a low proportion of pectic polysaccharides. ATR-FTIR data pointed to a higher proportion of xylans in stems than in leaves. Finally, attending the molecular mass of cell wall polysaccharides from leaves, pectin fractions showed the presence of populations of polysaccharides with lower molecular masses than those of hemicellulose fractions. [ABSTRACT FROM AUTHOR]