Effects of an experimental increase of temperature and drought on the photosynthetic performance of two ericaceous shrub species along a north-south European gradient
Effects of an experimental increase of temperature and drought on the photosynthetic performance of two ericaceous shrub species along a north-south European gradient
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DOI：
10.1007/s10021-004-0180-1
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发表时间：
2004-09-01
期刊：
影响因子：
3.7
通讯作者：
Tietema, A
中科院分区：
文献类型：
--
作者：
Llorens, L;Peñuelas, J;Tietema, A
在北欧和南欧国家，植物对气候变化的响应可能是不同的，因为不同的非生物因素限制了植物的生理活动。我们研究了两种欧洲温度和降水梯度(英国、丹麦、荷兰和西班牙)的灌木(多花杜鹃和马蹄莲)在实验温度和干旱条件下对其光合性能的影响。在每个地点，全年都在夜间进行被动增温处理，而干旱处理排除了生长季节6-10周的降雨事件。在1999年和2000年的生长季节，我们测量了叶片气体交换、叶绿素a荧光和叶片碳同位素比率(Delta(13)C)。从北部国家到南部国家，叶片净光合速率明显遵循一个梯度，这与可用水的地理梯度一致。因此，净光合速率与整个生长季的累积降雨量之间存在着很强的相关性。在四个地点，干旱植株的叶片气体交换速率低于对照植株。有趣的是，尽管叶片的光合作用速率随着降雨量的增加和干旱处理的反应而下降，但与测量前几个月的累积降雨量相比，干旱植株能够保持比对照植物更高的叶片光合作用速率。与对照相比，干旱植株的潜在光化学效率(F-v/F-m)值也较高，主要在中午。升温处理对所研究的瞬时生态生理变量中的任何一个都没有显著影响。
Plant ecophysiological changes in response to climatic change may be different in northern and southern European countries because different abiotic factors constrain plant physiological activity. We studied the effects of experimental warming and drought on the photosynthetic performance of two ericaceous shrubs (Erica multiflora and Calluna vulgaris) along a European gradient of temperature and precipitation (UK, Denmark, The Netherlands, and Spain). At each site, a passive warming treatment was applied during the night throughout the whole year, whereas the drought treatment excluded rain events over 6-10 weeks during the growing season. We measured leaf gas exchange, chlorophyll a fluorescence, and leaf carbon isotope ratio (delta(13)C) during the growing seasons of 1999 and 2000. Leaf net photosynthetic rates clearly followed a gradient from northern to southern countries in agreement with the geographical gradient in water availability. Accordingly, there was a strong correlation between net photosynthetic rates and the accumulated rainfall over the growing season. Droughted plants showed lower leaf gas exchange rates than control plants in the four sites. Interestingly, although leaf photosynthetic rates decreased along the precipitation gradient and in response to drought treatment, droughted plants were able to maintain higher leaf photosynthetic rates than control plants in relation to the accumulated rainfall over the months previous to the measurements. Droughted plants also showed higher values of potential photochemical efficiency (F-v/F-m) in relation to controls, mainly at midday. The warming treatment did not affect significantly any of the studied instantaneous ecophysiological variables.