DOI: 10.1007/s10533-015-0132-1
Scopus记录号: 2-s2.0-84944162223
论文题名: Using 2D NMR spectroscopy to assess effects of UV radiation on cell wall chemistry during litter decomposition
作者: Lin Y. ; King J.Y. ; Karlen S.D. ; Ralph J.
刊名: Biogeochemistry
ISSN: 0168-2563
EISSN: 1573-515X
出版年: 2015
卷: 125, 期: 3 起始页码: 427
结束页码: 436
语种: 英语
英文关键词: Cellulose
; Dryland
; HSQC (heteronuclear single-quantum coherence)
; Photo-mineralization
; Photo-oxidation
; Photo-priming
Scopus关键词: cells and cell components
; cellulose
; decomposition analysis
; environmental factor
; ether
; lignin
; magnetic field
; molecular analysis
; nuclear magnetic resonance
; photodegradation
; polysaccharide
; terrestrial ecosystem
; ultraviolet radiation
; Bromus diandrus
英文摘要: 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 (2.5 months during summer, and 1 year). Through fiber analysis by sequential digestion, we found that the litter hemicellulose fraction decreased significantly from 31.6 to 24.9 % after 1 year of decomposition. In litter exposed for 1 year, 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 1 year 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. © 2015, Springer International Publishing Switzerland. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/83475
Appears in Collections: 气候减缓与适应 气候变化事实与影响
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作者单位: Department of Geography, University of California, Santa Barbara, CA, United States; U.S. Department of Energy (DOE) Great Lakes Bioenergy Research Center, The Wisconsin Energy Institute, University of Wisconsin-Madison, Madison, WI, United States; Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, United States
Recommended Citation:
Lin Y.,King J.Y.,Karlen S.D.,et al. Using 2D NMR spectroscopy to assess effects of UV radiation on cell wall chemistry during litter decomposition[J]. Biogeochemistry,2015-01-01,125(3)