TY - JOUR
T1 - Distribution and carbon isotope patterns of diterpenoids and triterpenoids in modern temperate C 3 trees and their geochemical significance
AU - Diefendorf, Aaron F.
AU - Freeman, Katherine H.
AU - Wing, Scott L.
N1 - Funding Information:
We thank Laurie Eccles for laboratory preparation, Kevin Mueller and Heather Graham for sample collection and laboratory assistance, Emily Diefendorf for sample collection assistance, and Denny Walizer for instrumentation support. We thank Roger Summons, Katherine French, Ken Sawada and an anonymous reviewer for helpful and insightful revisions to the manuscript. This research was supported by the National Science Foundation Grant EAR-0844212 (to K.H.F.) and fellowship awards from the Penn State Biogeochemical Research Initiative for Education (BRIE) funded by the National Science Foundation IGERT Grant DGE-9972759 .
PY - 2012/5/15
Y1 - 2012/5/15
N2 - Tricyclic diterpenoids and pentacyclic triterpenoids are nearly exclusively produced by gymnosperms and angiosperms, respectively. Even though both classes of terpenoids have long been recognized as plant biomarkers, their potential use as phylogenetically specific δ 13C proxies remains largely unexplored. Little is known of how terpenoid abundance and carbon isotope composition vary either with plant phylogenetic position, functional group, or during synthesis. Here, we report terpenoid abundances and isotopic data for 44 tree species in 21 families, representing both angiosperms and gymnosperms, and both deciduous and evergreen leaf habits. Di- and triterpenoid abundances are significantly higher in evergreens compared to deciduous species, reflecting differences in growth strategies and increased chemical investment in longer-lived leaves. Carbon isotope abundances of terpenoid lipids are similar to leaf tissues, indicating biosynthetic isotope effects are small for both the MVA (-0.4‰) and MEP (-0.6‰) pathways. Leaf and molecular isotopic patterns for modern plants are consistent with observations of amber, resins and plant biomarkers in ancient sediments. The δ 13C values of ancient diterpenoids are higher than triterpenoids by 2-5‰, consistent with observed isotopic differences between gymnosperms and angiosperms leaves, and support the relatively small lipid biosynthetic effects reported here. All other factors being equal, evergreen plants will dominate the abundance of terpenoids contributed to soils, sediments and ancient archives, with similar inputs estimated for angiosperm and gymnosperm trees when scaled by litter flux.
AB - Tricyclic diterpenoids and pentacyclic triterpenoids are nearly exclusively produced by gymnosperms and angiosperms, respectively. Even though both classes of terpenoids have long been recognized as plant biomarkers, their potential use as phylogenetically specific δ 13C proxies remains largely unexplored. Little is known of how terpenoid abundance and carbon isotope composition vary either with plant phylogenetic position, functional group, or during synthesis. Here, we report terpenoid abundances and isotopic data for 44 tree species in 21 families, representing both angiosperms and gymnosperms, and both deciduous and evergreen leaf habits. Di- and triterpenoid abundances are significantly higher in evergreens compared to deciduous species, reflecting differences in growth strategies and increased chemical investment in longer-lived leaves. Carbon isotope abundances of terpenoid lipids are similar to leaf tissues, indicating biosynthetic isotope effects are small for both the MVA (-0.4‰) and MEP (-0.6‰) pathways. Leaf and molecular isotopic patterns for modern plants are consistent with observations of amber, resins and plant biomarkers in ancient sediments. The δ 13C values of ancient diterpenoids are higher than triterpenoids by 2-5‰, consistent with observed isotopic differences between gymnosperms and angiosperms leaves, and support the relatively small lipid biosynthetic effects reported here. All other factors being equal, evergreen plants will dominate the abundance of terpenoids contributed to soils, sediments and ancient archives, with similar inputs estimated for angiosperm and gymnosperm trees when scaled by litter flux.
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U2 - 10.1016/j.gca.2012.02.016
DO - 10.1016/j.gca.2012.02.016
M3 - Article
AN - SCOPUS:84859913177
SN - 0016-7037
VL - 85
SP - 342
EP - 356
JO - Geochimica et Cosmochimica Acta
JF - Geochimica et Cosmochimica Acta
ER -