Gill Allison L, Gallinat Amanda S, Sanders-DeMott Rebecca, Rigden Angela J, Short Gianotti Daniel J, Mantooth Joshua A, Templer Pamela H
Department of Biology and.
Department of Earth and Environment, Boston University, Boston, MA 02215, USA.
Ann Bot. 2015 Nov;116(6):875-88. doi: 10.1093/aob/mcv055. Epub 2015 May 11.
Many individual studies have shown that the timing of leaf senescence in boreal and temperate deciduous forests in the northern hemisphere is influenced by rising temperatures, but there is limited consensus on the magnitude, direction and spatial extent of this relationship.
A meta-analysis was conducted of published studies from the peer-reviewed literature that reported autumn senescence dates for deciduous trees in the northern hemisphere, encompassing 64 publications with observations ranging from 1931 to 2010.
Among the meteorological measurements examined, October temperatures were the strongest predictors of date of senescence, followed by cooling degree-days, latitude, photoperiod and, lastly, total monthly precipitation, although the strength of the relationships differed between high- and low-latitude sites. Autumn leaf senescence has been significantly more delayed at low (25° to 49°N) than high (50° to 70°N) latitudes across the northern hemisphere, with senescence across high-latitude sites more sensitive to the effects of photoperiod and low-latitude sites more sensitive to the effects of temperature. Delays in leaf senescence over time were stronger in North America compared with Europe and Asia.
The results indicate that leaf senescence has been delayed over time and in response to temperature, although low-latitude sites show significantly stronger delays in senescence over time than high-latitude sites. While temperature alone may be a reasonable predictor of the date of leaf senescence when examining a broad suite of sites, it is important to consider that temperature-induced changes in senescence at high-latitude sites are likely to be constrained by the influence of photoperiod. Ecosystem-level differences in the mechanisms that control the timing of leaf senescence may affect both plant community interactions and ecosystem carbon storage as global temperatures increase over the next century.
许多独立研究表明，北半球寒温带和温带落叶林叶片衰老的时间受气温上升影响，但对于这种关系的强度、方向和空间范围，人们的共识有限。
对同行评审文献中已发表的研究进行荟萃分析，这些研究报告了北半球落叶树的秋季衰老日期，涵盖64篇出版物，观测时间从1931年至2010年。
在所研究的气象测量指标中，10月气温是衰老日期最强的预测因子，其次是冷却度日、纬度、光周期，最后是月总降水量，不过高纬度和低纬度地区这种关系的强度有所不同。在北半球，低纬度地区（北纬25°至49°）秋季叶片衰老的延迟程度显著高于高纬度地区（北纬50°至70°），高纬度地区的衰老对光周期的影响更敏感，低纬度地区的衰老对温度的影响更敏感。与欧洲和亚洲相比，北美叶片衰老随时间的延迟更为明显。
结果表明，叶片衰老随时间推移且因温度而延迟，尽管低纬度地区叶片衰老随时间的延迟比高纬度地区显著更强。在考察一系列广泛的地点时，仅温度可能是叶片衰老日期的合理预测因子，但重要的是要考虑到高纬度地区温度诱导的衰老变化可能受到光周期的限制。随着下个世纪全球气温升高，控制叶片衰老时间的机制在生态系统层面的差异可能会影响植物群落相互作用和生态系统碳储存。
