Negligible influence of elevated UV-B radiation on leaf litter quality of Quercus robur

• Published in: Soil biology & biochemistry 2001-04, Vol.33 (4), p.659-665
• Main Authors: Newsham, K.K., Splatt, P., Coward, P.A., Greenslade, P.D., McLeod, A.R., Anderson, J.M.
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; Chemical, physicochemical, biochemical and biological properties; Fundamental and applied biological sciences. Psychology; Leaf litter chemistry; Organic matter; Physics, chemistry, biochemistry and biology of agricultural and forest soils; Quercus robur; Soil science; Stratospheric ozone depletion; UV-A and UV-B radiation
• ISSN: 0038-0717; 1879-3428
• DOI: 10.1016/S0038-0717(00)00210-8

We tested whether elevated UV-B radiation applied to Quercus robur, a principal climax species of northern Europe, would influence concentrations of polyphenolics (Folin–Denis tannins and lignin), phenylpropanoid moieties of lignin, carbohydrates (monosaccharides and holocellulose), or nutrient elements (K, Ca, Mg, P and N) in recently-abscised leaf litter. Saplings of Q. robur were exposed for 2 years at an outdoor facility in the UK to a 30% elevation above the ambient amount of erythemally-weighted UV-B (280–315 nm) radiation under arrays of fluorescent lamps with cellulose diacetate filters, which transmitted both UV-B and UV-A (315–400 nm) radiation. Saplings were also exposed to elevated UV-A alone under arrays of lamps with polyester filters and to ambient radiation under non-energised arrays of lamps. We found little evidence that elevated UV-B radiation influenced leaf litter quality. Data pooled for both years indicated an 8% increase in vanillic acid concentration in litter from polyester-filtered lamp arrays, relative to non-energised arrays, and 8% and 6% increases, respectively, in concentrations of acetovanillone in litter from polyester- and cellulose diacetate-filtered lamp arrays, relative to non-energised lamp arrays. Arabinose concentration in litter from cellulose diacetate-filtered lamp arrays was 3% higher than in litter from polyester-filtered arrays, and glucose concentration in litter from cellulose-diacetate filtered lamp arrays was increased by 6%, relative to non-energised arrays. There were no main effects of elevated UV on the concentrations of holocellulose, polyphenolics or nutrient elements. We conclude that exposure to elevated UV-B does not substantially influence the initial chemical composition of Q. robur leaf litter and that any increases in UV-B radiation arising from ozone depletion over northern mid-latitudes will be unlikely to affect nutrient cycling and decomposition in Quercus woodlands through effects on litter quality alone.