التفاصيل البيبلوغرافية
| العنوان: |
Direct effects of elevated UV-B radiation on the decomposition of Quercus robur leaf litter |
| المؤلفون: |
Roberts, J. D., Newsham, K. K., McLeod, A. R., Emmett, B. A., Greenslade, P. D. |
| المصدر: |
Oikos; Sep1997, Vol. 79 Issue 3, p592-602, 11p |
| مصطلحات موضوعية: |
PLANT litter |
| مستخلص: |
Decomposing Quercus robur L. leaf litter was exposed for 64 weeks atan outdoor facility to supplemental levels of UV-B radiation (280--315 nm) under treatment arrays of cellulose diacetate-filtered fluorescent lamps which also produce UV-A radiation (315--400 nm). Litter was also exposed to UV-A radiation alone under control arrays of polyester-filtered lamps and to ambient levels of solar radiation under arrays of unenergised lamps. The treatment corresponded to a 30% elevation above the ambient erythemally-weighted level of UV-B radiation. Litter was sampled after 11, 39 and 64 weeks and was examined for differences in mass loss, decomposition constants (k), chemical composition and the abundances of saprotrophic fungi. No effects of UV radiation on k values were recorded, but after 11 weeks, percentage mass lossof litter exposed to UV-B radiation under treatment arrays was 3% lower than under control arrays and 2% lower than under ambient arrays.After 39 weeks, litters exposed to UV-A radiation under control arrays had 10% lower total nitrogen contents and 13% higher C:N ratios than those litters exposed beneath ambient arrays. At the last sampling, litters exposed to supplemental UV-B radiation had 5% higher carboncontents than those under ambient arrays. A 2.4-fold increase in thefrequency of lamina particles of litter that were uncolonised by fungi was recorded in litter exposed to UV-B radiation under treatment arrays, compared to ambient arrays. The abundances of the saprotrophicfungi Cladosporium spp. and Acremonium persicinum (Nicot) W. Gams were decreased by 50% and 91%, respectively, under UV-B treatment arrays compared to ambient arrays, and the abundance of coelomycete conidiomata recorded on leaves was increased by 12% under treatment arrays,compared to ambient. Dactylella spp. were not recorded on litter exposed to UV-A radiation under control arrays and UV-A radiation applied under control and treatment arrays apparently increased the abundance of P [ABSTRACT FROM AUTHOR] |
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| قاعدة البيانات: |
Complementary Index |
