Oligosaccharides in foliage of Agropyron, Bromus, Dactylis, Festuca, Lolium and Phleum*

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Abstract
SUMMARY: Temperatures are frequently too cool on rangelands of the western United States for plant growth to occur during much of the time when soil moisture is most readily available. Altering plant metabolism to facilitate growth under cool temperatures holds considerable potential for improving forage production on these ranges. Sucrosyloligosaccharides in representative grasses were characterized. Sucrosyloligosaccharides facilitate the partitioning of carbohydrates outside the chloroplasts during growth at cool temperatures. Eight grasses (Bromus inermis Leys., B. tectorum L., Dactylis glomerata L., Lolium perenne L., Festuca arnndinacea Schreb., Phleum pratense L., and two accessions of ‘Hycrest’ a cross between Agropyron desertorum (Fischer ex. Link) Schultes and A. cristatum L. Gaertner were grown in controlled environments at 10/5 ± 1 °C day/night temperatures. Oligosaccharides extracted from lyophilized leaves were separated using anion exchange chromatography. The relative amounts and kinds of trisaccharides varied among species. All grass contained both raffinose and 1‐ketose. Neoketose was the dominant trisaccharide in Lolium and Festuca but was absent from both Agropyron hybrids. 6‐Kestose was present in all species except L. perenne. Extracts of L. perenne and F. arundinacea contained a trisaccharide containing glucose, fructose and galactose (1:1:1), tentatively given the trivial name ‘loliose’. The oligosaccharide pattern in L. perenne, both Bromus species, D. glomerata and P. pratense suggest the presence of simple polymeric fructan series. However, the series are different from the inulin series in Jerusalem artichoke tubers. In contrast, chromatograms of leaf extracts of F. arundinacea and both Agropyron accessions have complicated profiles which may reflect the presence of both linear and branched polymers in those species. The oligosaccharide profiles determined by anion exchange chromatography may have useful chemotaxonomic applications.