| UV-B辐射对亚热带森林凋落叶氮、磷元素释放的影响 |
| 摘要点击 2681 全文点击 1577 修订日期：2011-06-06 |
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| 中文关键词 UV-B辐射 凋落叶分解 亚热带 氮磷释放 养分循环 |
| 英文关键词 UV-B radiation leaf litter decomposition subtropical region release of N and P nutrient cycle |
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| 中文摘要 |
| UV-B辐射对凋落物分解过程的影响已成为全球变化生态学研究中的前沿和热点问题之一.采用分解袋法对自然和UV-B辐射滤减两种环境下亚热带6种代表性树种(杉木、马尾松、木荷、香樟、青冈和甜槠)凋落叶氮、磷元素的释放动态进行了研究.结果表明,凋落叶氮元素的动态表现为直接富集、释放-富集和释放-富集-释放3种模式,磷元素的动态表现为直接释放、富集-释放-富集和无明显变化3种模式.与对照相比,UV-B辐射滤减显著延缓了甜槠凋落叶氮元素及青冈和甜槠凋落叶磷元素的释放(P<0.05),但促进了香樟凋落叶磷元素的释放(P<0.05),对其他树种凋落叶的氮或磷释放无显著影响.凋落叶的初始氮含量和C/N比值不能解释氮释放动态,C/P比值可以部分解释磷的释放.全球环境变化背景下UV-B辐射在湿润亚热带地区森林生态系统过程中的作用尚需进一步认识和理解. |
| 英文摘要 |
| The release of nitrogen and phosphorus from leaf litter of six representative species, Cunninghamia lanceolata, Pinus massoniana, Schima superba, Cinnamanun camphora, Cyclobalanopsis glauca and Castanopsis eyeri, was investigated with litterbag method under ambient and reduced UV-B radiation (22.1% below ambient) treatments in subtropical region. The results showed that, the N dynamics exhibited three patterns: immobilization, mineralization-immobilization and mineralization-immobilization-mineralization. P dynamics also exhibited three different patterns: mineralization, immobilization-mineralization-immobilization and no large change. Compared with ambient treatment, the reduced treatment significantly delayed the N release from C. eyeri and P release from both C. glauca and C. eyeri (P<0.05),but significantly stimulated P release from C. camphora(P<0.05). The initial N contents and C ∶N ratios can not account for the N dynamics during leaf litter decomposition. The C ∶P ratios can partly explain the P dynamics during decomposition. The more works need to be done to better understand the role of UV-B radiation in the forest ecosystem in humid subtropical China under global environment change. |
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