Photodegradation alleviates the lignin bottleneck for carbon turnover in terrestrial ecosystems

• Autores: Austin, Amy Theresa; Méndez, M. Soledad; Ballaré, Carlos Luis
• Año de publicación: 2016
• Idioma: inglés
• Tipo de recurso: artículo
• Fuente: Proceedings of the National Academy of Sciences of the United States of America; Vol.113, no.16; 4392-4397; http://www.pnas.org/
• Materia: CARBON CYCLE; PLANT LITTER DECOMPOSITION; PHOTODEGRADATION; LIGNIN; UV RADIATION
• Institución: Universidad de Buenos Aires. Facultad de Agronomía

Fil: Austin, Amy Theresa. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura (IFEVA). Buenos Aires, Argentina.
Fil: Austin, Amy Theresa. CONICET – Universidad de Buenos Aires. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura (IFEVA). Buenos Aires, Argentina.
Fil: Austin, Amy Theresa. Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Buenos Aires, Argentina.
Fil: Méndez, M. Soledad. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura (IFEVA). Buenos Aires, Argentina.
Fil: Méndez, M. Soledad. CONICET – Universidad de Buenos Aires. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura (IFEVA). Buenos Aires, Argentina.
Fil: Ballaré, Carlos Luis. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura (IFEVA). Buenos Aires, Argentina.
Fil: Ballaré, Carlos Luis. CONICET – Universidad de Buenos Aires. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura (IFEVA). Buenos Aires, Argentina.
Fil: Ballaré, Carlos Luis. Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Buenos Aires, Argentina.
A mechanistic understanding of the controls on carbon storage and losses is essential for our capacity to predict and mitigate human impacts on the global carbon cycle. Plant litter decomposition is an important first step for carbon and nutrient turnover, and litter inputs and losses are essential in determining soil organic matter pools and the carbon balance in terrestrial ecosystems Photodegradation, the photochemical mineralization of organic matter, has been recently identified as a mechanism for previously unexplained high rates of litter mass loss in arid lands; however, the global significance of this process as a control on carbon cycling in terrestrial ecosystems is not known. Here we show that, across a wide range of plant species, photodegradation enhanced subsequent biotic degradation of leaf litter. Moreover, we demonstrate that the mechanism for this enhancement involves increased accessibility to plant litter carbohydrates for microbial enzymes. Photodegradation of plant litter, driven by UV radiation, and especially visible (blue-green) light, reduced the structural and chemical bottleneck imposed by lignin in secondary cell walls. In leaf litter from woody species, specific interactions with UV radiation obscured facilitative effects of solar radiation on biotic decomposition. The generalized effect of sunlight exposure on subsequent microbial activity, mediated by increased accessibility to cell wall polysaccharides, suggests that photodegradation is quantitatively important in determining rates of mass loss, nutrient release, and the carbon balance in a broad range of terrestrial ecosystems