A new field instrument for leaf volatiles reveals an unexpected vertical profile of isoprenoid emission capacities in a tropical forest
A new field instrument for leaf volatiles reveals an unexpected vertical profile of isoprenoid emission capacities in a tropical forest
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DOI：
10.3389/ffgc.2021.668228
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发表时间：
2021-02
期刊：
影响因子：
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通讯作者：
T. Taylor;W. Wisniewski;E. Alves;R. D. de Oliveira;S. Saleska
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作者：
T. Taylor;W. Wisniewski;E. Alves;R. D. de Oliveira;S. Saleska
植物叶片释放的挥发性类异戊二烯（VI），如异戊二烯和单萜，会显著改变植物生理和大气化学。然而，自20世纪50年代获得科学关注以来，对叶VI的实证研究主要局限于实验室实验和大气观测。在这里，我们介绍了一种新的现场仪器，旨在桥梁的规模从叶子到大气，使精确的VI检测在真实的时间从植物在其自然生态环境。在巴西亚马逊的实地活动，我们揭示了一个意想不到的分布叶排放能力（EC）的垂直轴的森林冠层，EC峰值在中间的冠层，而不是阳光照射的冠层表面，和高排放发生在林下专业物种。相比简单的解释，VI保护叶片免受热应力在炎热的冠层表面，我们的研究结果鼓励更细致入微的观点VI在植物中的适应性作用。我们推断，森林排放到大气中取决于冠层结构所施加的动态微环境，而不仅仅是冠层表面条件。我们提供了一个新的排放清单，从51个热带树种，揭示了中等的一致性EC内分类组。我们的独立便携式仪器提供实时检测和实时测量反馈，精度和检测限优于0.5 nmol m-2leaf s-1。我们将基于气体检测方法的仪器称为“PORCO”：有机化合物的光电离。我们提供了一个彻底的验证PORCO，并证明其能力，以检测生态驱动的叶片排放率的变化，从而加速一个新兴的科学领域：植物挥发物的生态学和生态生理学。纸张类型方法
Both plant physiology and atmospheric chemistry are substantially altered by the emission of volatile isoprenoids (VI), such as isoprene and monoterpenes, from plant leaves. Yet, since gaining scientific attention in the 1950’s, empirical research on leaf VI has been largely confined to laboratory experiments and atmospheric observations. Here, we introduce a new field instrument designed to bridge the scales from leaf to atmosphere, by enabling precision VI detection in real time from plants in their natural ecological setting. With a field campaign in the Brazilian Amazon, we reveal an unexpected distribution of leaf emission capacities (EC) across the vertical axis of the forest canopy, with EC peaking in the mid-canopy instead of the sun-exposed canopy surface, and high emissions occurring in understory specialist species. Compared to the simple interpretation that VI protect leaves from heat stress at the hot canopy surface, our results encourage a more nuanced view of the adaptive role of VI in plants. We infer that forest emissions to the atmosphere depend on the dynamic microenvironments imposed by canopy structure, and not simply on canopy surface conditions. We provide a new emissions inventory from 51 tropical tree species, revealing moderate consistency in EC within taxonomic groups. Our self-contained, portable instrument provides real-time detection and live measurement feedback with precision and detection limits better than 0.5 nmol m-2leaf s-1. We call the instrument ‘PORCO’ based on the gas detection method: photoionization of organic compounds. We provide a thorough validation of PORCO and demonstrate its capacity to detect ecologically driven variation in leaf emission rates and thus accelerate a nascent field of science: the ecology and ecophysiology of plant volatiles. Type of paper Method