Direct effects of elevated UV-B radiation on the decomposition of Quercus robur leaf litter
Direct effects of elevated UV-B radiation on the decomposition of Quercus robur leaf litter
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DOI：
10.2307/3546903
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发表时间：
1997-09-01
期刊：
影响因子：
3.4
通讯作者：
Emmett, BA
中科院分区：
文献类型：
--
作者：
Newsham, KK;McLeod, AR;Emmett, BA
分解栎在室外设施中，在也产生UV-A辐射（315-400 nm）的二乙酸纤维素过滤荧光灯的处理阵列下，将落叶暴露于补充水平的UV-B辐射（280-315 nm）64周。垃圾也暴露于UV-A辐射单独下的聚酯过滤灯的控制阵列和太阳辐射的环境水平下的阵列unenergised灯。该处理对应于高于UV-B辐射的环境辐射加权水平30%的升高。凋落物取样后11，39和64周，并进行了检查的质量损失，分解常数（k），化学成分和腐食真菌的丰度的差异。UV辐射对k值没有影响，但在11周后，暴露于UV-B辐射的处理阵列下的凋落物的质量损失百分比比对照阵列低3%，比环境阵列低2%。39周后，窝暴露于UV-A辐射下的控制阵列有10%的总氮含量低，13%的高C：N比暴露于环境阵列下的那些窝。在最后一次采样时，暴露于UV-B辐射的凋落物中碳含量比对照组高5%;暴露于UV-B辐射的凋落物中未被真菌定殖的叶片颗粒的频率比对照组高2.4倍。腐解真菌枝孢属（Cladosporium spp.）和顶孢霉Acremonium pelsicinum（Nicot）W. Gams分别下降了50%和91%，根据UV-B治疗阵列相比，环境阵列，和丰富的腔肠菌分生孢子记录在叶子上增加了12%，治疗阵列相比，环境。指状藻属在对照阵列下暴露于UV-A辐射的凋落物上没有记录到，并且在对照阵列和处理阵列下施加的UV-A辐射明显增加了多囊藻里斯的丰度。在垃圾上。紫外线辐射的影响较少的分解真菌的丰度，在叶组织中比那些开发落叶表面。我们的结论是，平流层臭氧消耗的结果，UV-B辐射通量的增加将有微妙的，但广泛的影响，在橡树林地的凋落物的分解。
Decomposing Quercus robur L. leaf litter was exposed for 64 weeks at an 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, bur after 11 weeks, percentage mass loss of 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 carbon contents than those under ambient arrays.A 2.4-fold increase in the frequency 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 saprotrophic fungi Cladosporium spp. and Acremonium pelsicinum (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 Polyscytalum fecundissimum Riess. on litter. UV radiation had fewer effects on the abundances of decomposer fungi that develop in leaf tissues than it did on those that develop on leaf litter surfaces. We conclude that increased fluxes of UV-B radiation as a result of stratospheric ozone depletion will have subtle but wide ranging impacts on the decomposition of litters in oak woodlands.