Staudt Michael, Rivet Coralie, Erdogan Meltem
CEFE, CNRS, EPHE, IRD Univ Montpellier Montpellier France.
Ecol Evol. 2025 Aug 31;15(9):e72093. doi: 10.1002/ece3.72093. eCollection 2025 Sep.
Knowledge of the intraspecific variability of volatiles produced by plants is central for estimating their fluxes from ecosystems and for understanding their evolution in an ecological and phylogenetic context. Past studies suggested that volatile emissions from Cork oak ( L.) exhibit a high degree of qualitative and quantitative polymorphism. However, the extent of inherent emission variability across its range is not known. We investigated leaf emissions, photosynthetic, and morphological traits of 241 Cork oak seedlings from ten provenances. To minimize environmental influences, emissions were determined at 30°C and saturating light on seed-grown saplings of similar age grown under the same conditions. All individuals, except for three apparent non-emitters, released the same five monoterpenes at a mean rate of 2559 ± 120 ng m s. Northern provenances tended to develop more sclerophyllous leaves with higher emission rates and lower photosynthetic rates than southern populations, resulting in significant different carbon losses by emissions. Independently, the emission composition varied discontinuously among individuals according to three distinct chemotypes, indicating inherent differences in the activity of two types of monoterpene synthases: one producing α-, β-pinene and sabinene, and the other limonene. Chemotype frequencies differed among provenances, particularly between South-Eastern Mediterranean and South-Western Atlantic provenances. Regarding leaf traits, we found no differences between chemotypes. The study confirms that Cork oak is a strong emitter of monoterpenes, the quality and quantity of which vary independently within its range. A comparison of the emission variability with that of other oak species suggests that a Pinene/sabinene chemotype is the ancestral form within the oak subgenus , which diversified during species radiation. This diversification is less pronounced in Cork oak than in other sympatric oaks, likely due to differential fragmentation and expansion of their ranges in the past.
了解植物产生的挥发性物质的种内变异性对于估计其从生态系统中的通量以及理解其在生态和系统发育背景下的进化至关重要。过去的研究表明，栓皮栎（L.）的挥发性物质排放表现出高度的定性和定量多态性。然而，其分布范围内固有排放变异性的程度尚不清楚。我们调查了来自十个种源的241株栓皮栎幼苗的叶片排放、光合和形态特征。为了尽量减少环境影响，在30°C和饱和光照条件下，对在相同条件下生长的年龄相似的种子苗进行排放测定。除了三个明显不排放的个体外，所有个体均以平均速率2559±120 ng m s释放相同的五种单萜。北方种源的叶子往往比南方种群的叶子更硬，排放率更高，光合速率更低，导致排放造成的碳损失显著不同。独立地，根据三种不同的化学型，个体之间的排放组成不连续变化，表明两种单萜合酶活性存在固有差异：一种产生α-、β-蒎烯和桧烯，另一种产生柠檬烯。化学型频率在种源之间存在差异，特别是在东南地中海和西南大西洋种源之间。关于叶片特征，我们发现化学型之间没有差异。该研究证实栓皮栎是单萜的强排放者，其质量和数量在其分布范围内独立变化。将排放变异性与其他栎树种进行比较表明，蒎烯/桧烯化学型是栎亚属中的祖先形式，在物种辐射期间发生了多样化。这种多样化在栓皮栎中不如在其他同域栎树中明显，可能是由于过去它们分布范围的不同破碎和扩张。
