caa a22 4500 605517681 CHVBK 20210128100721.0 cr unu---uuuuu 210128e20150901xx s 000 0 eng 10.1007/s10533-015-0132-1 doi (NATIONALLICENCE)springer-10.1007/s10533-015-0132-1 Using 2D NMR spectroscopy to assess effects of UV radiation on cell wall chemistry during litter decomposition [Elektronische Daten] [Yang Lin, Jennifer King, Steven Karlen, John Ralph] Litter chemistry is one of the most studied controls on decomposition in terrestrial ecosystems. Solar radiation has been shown to increase litter decomposition rates in arid ecosystems through the process of photodegradation. However, it remains unclear how photodegradation affects litter chemistry, especially the abundance and composition of lignin, which is thought to play a key role in photodegradation. Using two-dimensional nuclear magnetic resonance (2D NMR) spectroscopic methods, we quantified the molecular-level changes in litter chemistry associated with photodegradation. Litter of Bromus diandrus was exposed in the field to two levels of radiation [with and without ultraviolet (UV) wavelengths] and two durations of exposure (2.5months during summer, and 1year). Through fiber analysis by sequential digestion, we found that the litter hemicellulose fraction decreased significantly from 31.6 to 24.9% after 1year of decomposition. In litter exposed for 1year, the hemicellulose fraction was significantly lower in litter with UV exposure compared to litter without UV exposure (23.8 vs. 25.9%). These results indicate that UV photodegradation has a small but significant effect on litter chemistry compared to other decomposition processes. Even though fiber analysis showed no loss of total lignin, 2D NMR analysis demonstrated that UV exposure reduced the major lignin structural units containing β-aryl ether inter-unit linkages by 9% and decreased the relative abundance of lignin p-hydroxyphenyl units by 20%. The 2D NMR analysis also revealed that lignin guaiacyl units were preferentially lost after 1year of decomposition relative to the reference material, but no effects of UV exposure on guaiacyl units were observed. These results suggest that photodegradation causes partial degradation, not necessarily complete breakdown, of lignin structures. Our data also demonstrate that applications of 2D NMR methods are valuable for acquiring detailed information on lignin and polysaccharide chemistry during both biotic and abiotic decomposition processes. Springer International Publishing Switzerland, 2015 Photo-oxidation nationallicence Photo-mineralization nationallicence Photo-priming nationallicence Cellulose nationallicence Dryland nationallicence HSQC (heteronuclear single-quantum coherence) nationallicence Lin Yang Department of Geography, University of California, 93106-4060, Santa Barbara, CA, USA aut King Jennifer Department of Geography, University of California, 93106-4060, Santa Barbara, CA, USA aut Karlen Steven U.S. Department of Energy (DOE) Great Lakes Bioenergy Research Center, The Wisconsin Energy Institute, University of Wisconsin-Madison, 53726, Madison, WI, USA aut Ralph John U.S. Department of Energy (DOE) Great Lakes Bioenergy Research Center, The Wisconsin Energy Institute, University of Wisconsin-Madison, 53726, Madison, WI, USA aut Biogeochemistry Springer International Publishing 125/3(2015-09-01), 427-436 0168-2563 125:3<427 2015 125 10533 https://doi.org/10.1007/s10533-015-0132-1 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 brief-communication jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s10533-015-0132-1 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Lin Yang Department of Geography, University of California, 93106-4060, Santa Barbara, CA, USA aut NATIONALLICENCE 700 1- King Jennifer Department of Geography, University of California, 93106-4060, Santa Barbara, CA, USA aut NATIONALLICENCE 700 1- Karlen Steven U.S. Department of Energy (DOE) Great Lakes Bioenergy Research Center, The Wisconsin Energy Institute, University of Wisconsin-Madison, 53726, Madison, WI, USA aut NATIONALLICENCE 700 1- Ralph John U.S. Department of Energy (DOE) Great Lakes Bioenergy Research Center, The Wisconsin Energy Institute, University of Wisconsin-Madison, 53726, Madison, WI, USA aut NATIONALLICENCE 773 0- Biogeochemistry Springer International Publishing 125/3(2015-09-01), 427-436 0168-2563 125:3<427 2015 125 10533