Impact of drought on seasonal monoterpene emissions from Quercus ilex in southern France
Impact of drought on seasonal monoterpene emissions from Quercus ilex in southern France
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干旱对法国南部栎属冬青属季节性单萜排放的影响
DOI：
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发表时间：
2002
期刊：
影响因子：
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通讯作者：
J. Kesselmeier
中科院分区：
文献类型：
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作者：
M. Staudt;S. Rambal;R. Joffre;J. Kesselmeier
[1]我们研究了单萜排放的万年青橡树栎冬青暴露在不同程度的夏季干旱，以研究在地中海地区的排放量的季节性变化，并测试其中的水限制的作用。测量了7个运动之间的6月和1月在两个相邻的网站，其中一个自然供水减少了地面屋顶生长的成熟树木的完整叶片。在这两个地点，实际发射率以及光和温度归一化发射率（即，平均排放因子（EF）在季节中显著变化：平均EF从6月到7月增加到夏季的最大值，介于5.2和9.4 nmol m−2叶面积s−1（12-21 μg g−1叶干质量h−1）之间，10月和11月下降，1月达到最小值约0.77 nmol m−2 s−1（1.7 μg g−1 h−1）。从6月到7月，减少供水的树木的平均EF显着低于正常供水的树木。在夏季降低EF是由较低的黎明前水势，叶片蒸腾，光合作用和气孔导度相对于对照树。结果表明，在自然条件下，Q.冬青生境EF的季节演变遵循一个明显的夏-冬循环，其形状和强度可以通过夏季干旱来改变。
[1] We studied monoterpene emissions from the evergreen oak Quercus ilex exposed to different levels of summer drought to examine the seasonal variation of emissions in the Mediterranean area and to test the role of water limitations therein. Measurements were made in seven campaigns between June and January on intact leaves of mature trees growing in two adjacent sites, in one of which the natural water supply was reduced by a ground roof. In both sites, actual emission rates as well as light- and temperature-normalized emission rates (i.e., emission factor (EF)) significantly changed during the seasons: Mean EFs increased from June to July to a broad summer maximum between 5.2 and 9.4 nmol m−2 leaf area s−1 (12–21 μg g−1 leaf dry mass h−1), dropped in October and November and reached a minimum of about 0.77 nmol m−2 s−1 (1.7 μg g−1 h−1) in January. From June to July, mean EFs of the trees with reduced water supply were significantly lower than those of trees with normal water supply. The lowered EF in summer was paralleled by lower predawn water potentials, leaf transpiration, photosynthesis and stomatal conductance with respect to control trees. The results suggest that in natural Q. ilex habitats the seasonal evolution of EF follows a marked summer-winter cycle whose shape and intensity can be modified by summer drought.