Compound-specific deltaD-delta13C analyses of n-alkanes extracted from terrestrial and aquatic plants.
Stable hydrogen and carbon isotopic compositions of individual n-alkanes were determined for various terrestrial plants (33 samples including 27 species) and aquatic plants (six species) in natural environments from Japan and Thailand. In C3 plants, n-alkanes extracted from angiosperms have a deltaD value of -152+/-26 per thousand (relative to Standard Mean Ocean Water [SMOW]) and delta13C value of -36.1+/-2.7 per thousand (relative to Peedde Belemnite [PDB]), and those from gymnosperms have a deltaD value of -149+/-16 per thousand and delta13C value of -31.6+/-1.7 per thousand. Angiosperms have n-alkanes depleted in 13C relative to gymnosperms. n-Alkanes from C4 plants have a deltaD value of -171+/-12 per thousand and delta13C value of -20.5+/-2.1 per thousand, being a little depleted in D and much enriched in 13C compared to C3 plants. n-Alkanes of CAM plants are a little depleted in D and vary widely in delta13C relative to those of C3 and C4 plants. In aquatic plants, n-alkanes from freshwater plants have a deltaD value of -187+/-16 per thousand and delta13C value of -25.3+/-1.9 per thousand, and those from seaweeds have a deltaD value of -155+/-34 per thousand and delta13C value of -22.8+/-1.0 per thousand. All n-alkanes from various plant classes are more depleted in D and 13C relative to environmental water and bulk tissue, respectively. In addition, the hydrogen and carbon isotopic fractionations during n-alkane synthesis are distinctive for these various plant classes. While C3 plants have smaller isotopic fractionations in both D and 13C, seaweed has larger isotopic fractionations.
Department of Chemistry, Tokyo Metropolitan University, 1-1, Minami-Ohsawa, Hachioji, 192-0397, Tokyo, Japan. rikie@comp.metro-u.ac.jp
Yoshito
Y
Chikaraishi
Hiroshi
H
Naraoka
D000473:Alkanes / Q000737:chemistry* / Q000493:pharmacokinetics; D002247:Carbon Isotopes / Q000032:analysis*; D032462:Cycadopsida / Q000737:chemistry* / Q000378:metabolism; D003903:Deuterium / Q000032:analysis*; D004777:Environment; D019684:Magnoliopsida / Q000737:chemistry* / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000493:pharmacokinetics
D000473:Alkanes; D002247:Carbon Isotopes; D014874:Water Pollutants, Chemical; D003903:Deuterium