Reudler J H, Elzinga Jelmer A
Department of Biological and Environmental Science, University of Jyväskylä, P.O. Box 35, 40014, Jyväskylä, Finland.
J Chem Ecol. 2015 Feb;41(2):139-48. doi: 10.1007/s10886-015-0550-5. Epub 2015 Jan 31.
Spatial variation in chemical defense of plants can be caused by genetic, biotic, and abiotic factors. For example, many plants exhibit a latitudinal cline in chemical defense, potentially due to latitudinal variation in abiotic environmental factors such as the light regime during the growing season. In the worldwide distributed Plantago lanceolata, the levels of deterrent iridoid glycosides (IGs), aucubin and catalpol, vary geographically, including latitudinally. To examine whether latitudinal variation in photoperiod can explain part of this geographic variation, plants from the Netherlands and Finland were exposed to two different photoperiods, simulating the Dutch (middle European) and Finnish (northern European) light period during the growing season. The experiment showed that although most variation in IG content was genetic, plants from both Dutch and Finnish origin produce relatively more catalpol under a northern European than under a middle European photoperiod. Our results confirm that latitudinal effects on photoperiod can contribute to geographic variation in plant defense chemistry, which should be considered when studying latitudinal clines in plant-enemy interactions.
植物化学防御的空间变异可能由遗传、生物和非生物因素引起。例如，许多植物在化学防御方面呈现出纬度梯度变化，这可能是由于非生物环境因素的纬度差异，如生长季节的光照条件。在全球分布的车前草中，具有威慑作用的环烯醚萜苷（IGs）、桃叶珊瑚苷和梓醇的含量存在地理差异，包括纬度上的差异。为了研究光周期的纬度变化是否能解释这种地理变异的一部分，将来自荷兰和芬兰的植物暴露于两种不同的光周期下，模拟生长季节荷兰（中欧）和芬兰（北欧）的光照时长。实验表明，尽管IG含量的大部分变异是由遗传因素导致，但来自荷兰和芬兰的植物在北欧光周期下比在中欧光周期下产生的梓醇相对更多。我们的结果证实，光周期的纬度效应会导致植物防御化学的地理变异，在研究植物与天敌相互作用的纬度梯度时应予以考虑。
