The Nurturing Station for the State Key Laboratory of Subtropical Silviculture and Zhejiang Provincial Key Laboratory of Carbon Cycling and Carbon Sequestration in Forest Ecosystems, Zhejiang A & F University, Lin'an, China.
PLoS One. 2013 Jun 20;8(6):e68858. doi: 10.1371/journal.pone.0068858. Print 2013.
Ultraviolet-B (UV-B) exposure in the course of litter decomposition may have a direct effect on decomposition rates via changing states of photodegradation or decomposer constitution in litter while UV-B exposure during growth periods may alter chemical compositions and physical properties of plants. Consequently, these changes will indirectly affect subsequent litter decomposition processes in soil. Although studies are available on both the positive and negative effects (including no observable effects) of UV-B exposure on litter decomposition, a comprehensive analysis leading to an adequate understanding remains unresolved. Using data from 93 studies across six biomes, this introductory meta-analysis found that elevated UV-B directly increased litter decomposition rates by 7% and indirectly by 12% while attenuated UV-B directly decreased litter decomposition rates by 23% and indirectly increased litter decomposition rates by 7%. However, neither positive nor negative effects were statistically significant. Woody plant litter decomposition seemed more sensitive to UV-B than herbaceous plant litter except under conditions of indirect effects of elevated UV-B. Furthermore, levels of UV-B intensity significantly affected litter decomposition response to UV-B (P<0.05). UV-B effects on litter decomposition were to a large degree compounded by climatic factors (e.g., MAP and MAT) (P<0.05) and litter chemistry (e.g., lignin content) (P<0.01). Results suggest these factors likely have a bearing on masking the important role of UV-B on litter decomposition. No significant differences in UV-B effects on litter decomposition were found between study types (field experiment vs. laboratory incubation), litter forms (leaf vs. needle), and decay duration. Indirect effects of elevated UV-B on litter decomposition significantly increased with decay duration (P<0.001). Additionally, relatively small changes in UV-B exposure intensity (30%) had significant direct effects on litter decomposition (P<0.05). The intent of this meta-analysis was to improve our understanding of the overall effects of UV-B on litter decomposition.
紫外-B（UV-B）辐射在凋落物分解过程中可能通过改变凋落物的光降解状态或分解者组成直接影响分解速率，而在生长期间的 UV-B 辐射可能改变植物的化学成分和物理性质。因此，这些变化将间接影响土壤中随后的凋落物分解过程。尽管已经有研究探讨了 UV-B 辐射对凋落物分解的正面和负面影响（包括无观测到的影响），但仍未解决对这些影响进行综合分析以充分理解的问题。本研究使用来自六个生物群落的 93 项研究的数据进行了介绍性荟萃分析，结果发现，增强的 UV-B 直接增加了凋落物分解速率 7%，间接增加了 12%，而减弱的 UV-B 直接降低了凋落物分解速率 23%，间接增加了凋落物分解速率 7%。然而，正面和负面影响均不具有统计学意义。与草本植物凋落物相比，木本植物凋落物似乎对 UV-B 更敏感，除了在增强的 UV-B 的间接影响下。此外，UV-B 强度水平显著影响了凋落物对 UV-B 的分解响应（P<0.05）。气候因素（如年平均降水量和年平均温度）（P<0.05）和凋落物化学性质（如木质素含量）（P<0.01）极大地加剧了 UV-B 对凋落物分解的影响。结果表明，这些因素可能掩盖了 UV-B 对凋落物分解的重要作用。在研究类型（野外实验与实验室培养）、凋落物形式（叶片与针叶）和分解持续时间方面，均未发现 UV-B 对凋落物分解的影响存在显著差异。增强的 UV-B 对凋落物分解的间接影响随着分解持续时间的增加而显著增加（P<0.001）。此外，UV-B 暴露强度的相对较小变化（30%）对凋落物分解具有显著的直接影响（P<0.05）。本荟萃分析的目的是提高我们对 UV-B 对凋落物分解的总体影响的理解。
