Low temperature-induced modifications of cell wall content and polysaccharide composition in leaves of winter oilseed rape (Brassica napus L-var. oleifera L.)

Pronounced modifications in cell wall content and polysaccharide composition were observed in the young leaves of winter oilseed rape plants (Brassica napus L, var, oleifera L. cv Jantar) grown for 3 weeks in cold (2 degrees C) and then exposed to a brief freezing and thawing treatment (-5 degrees C for 18 h). In the cold-grown leaf blades, the increased cell wall content was associated with higher levels of non-covalently bound pectins. The content of galactose, arabinose and glucose in pectins and of galactose and arabinose in hemicelluloses also increased in these leaves. Exposure of cold-acclimated plants to a freeze-thaw treatment resulted in decreased cell wall content, reduced levels of non-covalently bound pectins and decreased contents of xylose and glucose in the hemicellulose fraction. Our findings indicate that the pattern of modifications of cell wall content and polysaccharide composition depends on the range of temperatures the plant has been exposed to. The role of the cell wall in cold-acclimated and freezing treated plants is discussed. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.