Interspecific variation in bulk tissue, fatty acid and monosaccharide δ13C values of leaves from a mesotrophic grassland plant community

The leaves of 37 grass, herb, shrub and tree species were collected from a mesotrophic grassland to assess natural variability in bulk, fatty acid and monosaccharide delta C-13 values of leaves from one plant community. The leaf tissue mean bulk delta C-13 value was -29.3 parts per thousand. No significant differences between tissue bulk delta C-13 values with life form were determined (P=0.40). On average, C-16:0, C-18:2 and C-18:3 constituted 89% of leaf tissue total fatty acids, whose delta C-13 values were depleted compared to whole leaf tissues. A general interspecific (between different species) trend for fatty acids delta C-13 values was observed, i.e. delta C-13(16:0) < delta C-13(18:2) < delta C-13(18:3), although these values ranged widely between species, e.g. C-16:0 (-34.7 parts per thousand, Alisma plantago-aquatica; -44.0 parts per thousand, Leucanthemum vulgare), C-18:2 (-33.3 parts per thousand, Acer campestre; -44.2 parts per thousand, L. vulgare;) and C-18:3 (-34.3 parts per thousand, Bellis perennis; -41.8 parts per thousand, Plantago lanceolata). Average relative abundances of leaf monosaccharides arabinose, xylose, mannose, galactose and glucose were 12%, 13%, 5%, 12% and 54%, respectively. Mean delta C-13 values of these monosaccharides were -26.6 parts per thousand (arabinose), -27.2 parts per thousand (xylose), -30.9 parts per thousand (mannose), -30.0 parts per thousand (galactose) and -29.0 parts per thousand (glucose). The general relationship between individual monosaccharide delta C-13 values, delta C-13(arbinose) > delta C-13(xylose) > delta C-13(glucose) > delta C-13(galactose), was consistently observed. Therefore, we have shown (i) diversity in compound-specific delta C-13 values contributing to leaf bulk delta C-13 values; (ii) interspecific variability between bulk and compound-specific delta C-13 values of leaves of individual grassland species, and (iii) trends between individual fatty acid and monosaccharide delta C-13 values common to leaves of all species within one plant community. (C) 2008 Published by Elsevier Ltd.