The effect of lignin photodegradation on decomposability of Calamagrostis epigeios grass litter

Frouz, Jan; Cajthaml, Tomáš; Mudrák, Ondřej

doi:10.1007/s10532-011-9479-8

Cited by 39 publications

(36 citation statements)

References 27 publications

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“…Some studies reported that degradation of cellulose and/or hemicellulose is responsible for litter mass loss under UV exposure (Rozema et al 1997, Brandt et al 2007, 2010. Alternatively, we speculate that photodegradation breaks down encrusting lignin and exposes protected cellulose for biological decomposition (Henry et al 2008, Austin and Ballar e 2010, Brandt et al 2010, Frouz et al 2011. Talbot et al (2011) found that chemical protection due to the cross-linking between lignins and polysaccharides allowed lignin to control the total decay rates.…”

Section: Discussionmentioning

confidence: 90%

Simulation of the effects of photodecay on long‐term litter decay using DayCent

et al. 2016

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Abstract. Recent studies have found that solar ultraviolet (UV) radiation significantly shifts the mass loss and nitrogen dynamics of plant litter decomposition in semi-arid and arid ecosystems. In this study, we examined the role of photodegradation in litter decomposition by using the DayCent-UV biogeochemical model. DayCent-UV incorporated the following mechanisms related to UV radiation: (1) direct photolysis, (2) facilitation of microbial decomposition via production of labile materials, and (3) microbial inhibition effects. We also allowed maximum photodecay rate of the structural litter pool to vary with litter's initial lignin fraction in the model. We calibrated DayCent-UV with observed ecosystem variables (e.g., volumetric soil water content, live biomass, actual evapotranspiration, and net ecosystem exchange), and validated the optimized model with Long-Term Intersite Decomposition Experiment (LIDET) observations of remaining carbon and nitrogen at three semi-arid sites in Western United States. DayCent-UV better simulated the observed linear carbon loss patterns and the persistent net nitrogen mineralization in the 10-year LIDET experiment at the three sites than the model without UV decomposition. In the DayCent-UV equilibrium model runs, UV decomposition increased aboveground and belowground plant production, surface net nitrogen mineralization, and surface litter nitrogen pool, but decreased surface litter carbon, soil net nitrogen mineralization, and mineral soil carbon and nitrogen. In addition, UV decomposition had minimal impacts on trace gas emissions and biotic decomposition rates. The model results suggest that the most important ecological impact of photodecay of surface litter in dry grasslands is to increase N mineralization from the surface litter (25%), and decay rates of the surface litter (15%) and decrease the organic soil carbon and nitrogen (5%).

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Section: Discussionmentioning

confidence: 90%

Simulation of the effects of photodecay on long‐term litter decay using DayCent

et al. 2016

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“…) among the six plant materials used in our study suggests that the chemical composition of organic matter may be an important factor during abiotic litter decomposition. Several studies have reported significant chemical alteration of organic matter, in particular lignin, following solar or UV radiation exposure (Austin & Ballare, ; Feng et al ., ; Frouz et al ., ). Supporting this idea, basswood sheets showed the highest gas production rates for all three C‐based gases (Fig.…”

Section: Discussionmentioning

confidence: 97%

An accounting of C‐based trace gas release during abiotic plant litter degradation

Lee

Rahn

Throop

2011

Global Change Biology

116

120

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Recent studies showed that photochemical breakdown (photodegradation) of plant material accounts for a substantial portion of litter decomposition and subsequent trace gas release in ecosystems under high radiative load and low precipitation. In the absence of solar radiation, thermal degradation may also cause trace gas release at temperatures below the ignition point. These observations suggest that the abiotic processes of photodegradation and thermal degradation of plant litter may be important in understanding global trace gas budgets. In a laboratory incubation study, we performed a simultaneous carbon (C) accounting of CO 2 , CO, and CH 4 produced as a byproduct of photodegradation and thermal degradation of six different plant litter types that varied in chemical composition. The patterns of trace gas release during photodegradation and thermal degradation differed considerably across the six plant materials, suggesting that chemical composition of litter may influence the rates of abiotic degradation. There was a strong positive correlation between the rates of trace gas release during photodegradation and temperature. A significant portion of trace gases were produced during low temperature (< 100°C) thermal degradation of litter in the absence of solar radiation, which was also positively correlated to temperature. In addition, both thermal degradation and photodegradation occurred in the absence of O 2 . This indicates that the mechanism formerly accepted as photo-oxidation may only be one of several photodegradation processes. We speculate that the direct breakdown of chemical groups such as carboxyl, carbonyl, and methoxyl groups may result in CO 2 , CO, and CH 4 release. We suggest that the combined processes of thermal and photodegradation of litter may be a previously under accounted source of Cbased trace gases from terrestrial systems.

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“…In field experiments, UV exposure enhanced decay, as well as fungal abundance and extracellular enzyme activity in litter (Baker & Allison, ). Austin and Vivanco () found that exposure to both solar UV and blue radiation accelerated decay, as well as the decay of this litter in subsequent field incubations that promoted microbial degradation, and Frouz et al () found that litter exposed to more sunlight had higher subsequent respiration rates when buried in the soil. Our findings also suggest that the likely mechanism for this photopriming was the sunlight‐driven conversion of insoluble to water‐soluble compounds that improved the quality of litter for microbes, based on: (a) respiration rates in both initial and final litter were strongly correlated with water‐soluble fractions in litter (Figures , ), (b) respiration rates and water‐soluble fractions were higher in litter in full sun (Figure c,d), and (c) microbial respiration rates were notably higher at high water‐soluble fractions in litter in full sun (Figure c), suggesting that UV exposure promoted the formation of higher‐quality compounds.…”

Section: Discussionmentioning

confidence: 99%

Desert leaf litter decay: Coupling of microbial respiration, water‐soluble fractions and photodegradation

Day

Bliss

Tomes

et al. 2018

Global Change Biology

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The mechanisms of plant litter decay in drylands are poorly understood, limiting the accuracy of nutrient-cycling models for these systems. We monitored the decay of 12 leaf litter types on the soil surface of the Sonoran Desert for 34 months and assessed what traits predicted mass loss and how exposure to different wavebands of sunlight influenced mass loss. Mass loss varied considerably among litter types, ranging from 42%-96% after 34 months in full sunlight. Traditional indices of litter quality (e.g., initial C:N or lignin:N ratios) failed to predict differences in mass loss among litter types. The strongest predictor of mass loss was the microbial respiration rate of initial litter, which explained 45%-54% of the variation in loss among litter types. Microbial respiration rates were not correlated with traditional indices of litter quality, but were positively correlated with the water-soluble fraction in litter and concentrations of dissolved organic C in this fraction. Traditional indices of litter quality failed to predict decay likely because they did a poor job of predicting microbial degradability of litter, not because microbial degradation was a minor driver of decay. In all radiation-exposure treatments, water-soluble fractions and respiration rates increased through decay and were several times higher after 34 months than initially. Hence, labile pools and microbial degradability of litter increased through decay in contrast to traditional views that labile pools decline and constrain microbes. Litter exposed to UV or UV through blue radiation wavelengths, lost on average 1.3 times or 1.5 times more mass, respectively, than litter not exposed to these wavebands. The magnitude of this photodegradation was greater in litter types that had higher initial concentrations of hemicellulose and cellulose per unit surface area. Litter exposed to full sun had higher water-soluble fractions and usually had higher respiration rates, illustrating that sunlight accelerated microbial degradation by increasing labile pools. The processes driving litter decay appeared to differ appreciably from mesic systems and involved strong couplings between abiotic and biotic drivers.

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The effect of lignin photodegradation on decomposability of Calamagrostis epigeios grass litter

Cited by 39 publications

References 27 publications

Simulation of the effects of photodecay on long‐term litter decay using DayCent

Simulation of the effects of photodecay on long‐term litter decay using DayCent

An accounting of C‐based trace gas release during abiotic plant litter degradation

Desert leaf litter decay: Coupling of microbial respiration, water‐soluble fractions and photodegradation

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