Photodegradation is considered as a universal contributing factor to litter decomposition and carbon(C)cycling within the Earth’s biomes.Identifying how solar radiation modifies the molecular structure of litter is e...Photodegradation is considered as a universal contributing factor to litter decomposition and carbon(C)cycling within the Earth’s biomes.Identifying how solar radiation modifies the molecular structure of litter is essen-tial to understand the mechanism controlling its decom-position and reaction to shifts in climatic conditions and land-use.In this study,we performed a spectral-attenuation experiment following litter decomposition in an understory and gap of a temperate deciduous forest.We found that short-wavelength visible light,especially blue light,was the main factor driving variation in litter molecular struc-ture of Fagus crenata Blume,Quercus crispula Blume,Acer carpinifolium Siebold&Zuccarini and Betula platyphylla Sukaczev,explaining respectively 56.5%,19.4%,66.3%,and 16.7%of variation in its chemical composition.However,the variation also depended on canopy openness:Only in the forest gap was lignin aromatic C negatively associated with C-oxygen(C–O)bonding in polysaccharides receiv-ing treatments containing blue light of the full spectrum of solar radiation.Regardless of species,the decomposition index of litter that explained changes in mass and lignin loss was driven by the relative content of C–O stretching in poly-saccharides and lignin aromatic C.The results suggest that the availability of readily degradable polysaccharides pro-duced by the reduction in lignin aromatic C most plausibly explains the rate of litter photodegradation.Photo-products of photodegradation might augment the C pool destabilized by the input of readily degradable organic compounds(i.e.,polysaccharides).展开更多
Background Photodegradation of plant litter plays a pivotal role in the global carbon(C) cycle. In temperate forest ecosystems, the exposure of plant litter to solar radiation can be significantly altered by changes i...Background Photodegradation of plant litter plays a pivotal role in the global carbon(C) cycle. In temperate forest ecosystems, the exposure of plant litter to solar radiation can be significantly altered by changes in autumn phenol-ogy and snow cover due to climatic change. How this will affect litter decomposition and nutrient dynamic interact-ing with forest canopy structure(understorey vs. gaps) is uncertain. In the present study, we conducted a field experi-ment using leaf litter of early-fall deciduous Betula platyphylla(Asian white birch) and late-fall deciduous Quercus mongolica(Mongolian oak) to explore the effect of change in autumn solar radiation on dynamics of litter decompo-sition in a gap and understorey of a temperate mixed forest.Results Exposure to the full-spectrum of not only significantly increased the loss of mass, C, and lignin, but also mod-ified N loss through both immobilization and mineralization during the initial decomposition during autumn canopy opening, irrespective of canopy structure and litter species. These effects were mainly driven by the blue-green spectral region of sunlight. Short-term photodegradation by autumn solar radiation had a positive legacy effect on the later decomposition particularly in the forest gap, increasing mass loss by 16% and 19% for Asian white birch and Mongolia oak, respectively.Conclusions Our results suggest that earlier autumn leaf-fall phenology and/or later snow cover due to land-use or climate change would increase the exposure of plant organic matter to solar radiation, and accelerate ecosys-tem processes, C and nutrient cycling in temperate forest ecosystems. The study provides a reference for predictive research on carbon cycling under the background of global climate change.展开更多
基金supported by the National Natural Science Foundation of China (32122059)the National Key R&D Program of China(2021YFD2200402)+5 种基金the Chinese Academy of Sciences Young Talents Programthe LiaoNing Revitalization Talents Program (XLYC2007016) to QWW2024 Joint Fund Project Funding Program (2023-MSBA-137) to JJDChinese Academy of Sciences President's International Fellowship Initiative (2022VCA0010)the Japan Society for the Promotion of Science (KAKENHI,17F17403) to QWW and HKAcademy of Finland Project(324555) to TMR
文摘Photodegradation is considered as a universal contributing factor to litter decomposition and carbon(C)cycling within the Earth’s biomes.Identifying how solar radiation modifies the molecular structure of litter is essen-tial to understand the mechanism controlling its decom-position and reaction to shifts in climatic conditions and land-use.In this study,we performed a spectral-attenuation experiment following litter decomposition in an understory and gap of a temperate deciduous forest.We found that short-wavelength visible light,especially blue light,was the main factor driving variation in litter molecular struc-ture of Fagus crenata Blume,Quercus crispula Blume,Acer carpinifolium Siebold&Zuccarini and Betula platyphylla Sukaczev,explaining respectively 56.5%,19.4%,66.3%,and 16.7%of variation in its chemical composition.However,the variation also depended on canopy openness:Only in the forest gap was lignin aromatic C negatively associated with C-oxygen(C–O)bonding in polysaccharides receiv-ing treatments containing blue light of the full spectrum of solar radiation.Regardless of species,the decomposition index of litter that explained changes in mass and lignin loss was driven by the relative content of C–O stretching in poly-saccharides and lignin aromatic C.The results suggest that the availability of readily degradable polysaccharides pro-duced by the reduction in lignin aromatic C most plausibly explains the rate of litter photodegradation.Photo-products of photodegradation might augment the C pool destabilized by the input of readily degradable organic compounds(i.e.,polysaccharides).
基金funded by the National Natural Science Foundation of China(32122059)the National Key R&D Program of China(2021YFD2200402)+3 种基金Chi‑nese Academy of Sciences Young Talents Program,and Liaoning Revitalization Talents Program(XLYC2007016)to QWWby Chinese Academy of Sciences President’s International Fellowship Initiative(2022VCA0010)the Japan Society for the Promotion of Science(KAKENHI,17F17403)to QWW and HKAcademy of Finland Project(324555)to TMR.
文摘Background Photodegradation of plant litter plays a pivotal role in the global carbon(C) cycle. In temperate forest ecosystems, the exposure of plant litter to solar radiation can be significantly altered by changes in autumn phenol-ogy and snow cover due to climatic change. How this will affect litter decomposition and nutrient dynamic interact-ing with forest canopy structure(understorey vs. gaps) is uncertain. In the present study, we conducted a field experi-ment using leaf litter of early-fall deciduous Betula platyphylla(Asian white birch) and late-fall deciduous Quercus mongolica(Mongolian oak) to explore the effect of change in autumn solar radiation on dynamics of litter decompo-sition in a gap and understorey of a temperate mixed forest.Results Exposure to the full-spectrum of not only significantly increased the loss of mass, C, and lignin, but also mod-ified N loss through both immobilization and mineralization during the initial decomposition during autumn canopy opening, irrespective of canopy structure and litter species. These effects were mainly driven by the blue-green spectral region of sunlight. Short-term photodegradation by autumn solar radiation had a positive legacy effect on the later decomposition particularly in the forest gap, increasing mass loss by 16% and 19% for Asian white birch and Mongolia oak, respectively.Conclusions Our results suggest that earlier autumn leaf-fall phenology and/or later snow cover due to land-use or climate change would increase the exposure of plant organic matter to solar radiation, and accelerate ecosys-tem processes, C and nutrient cycling in temperate forest ecosystems. The study provides a reference for predictive research on carbon cycling under the background of global climate change.
