The Tree Drought Emission MONitor (Tree DEMON), an innovative system for assessing biogenic volatile organic compounds emission from plants

Abstract

BackgroundBiogenic volatile organic compounds (BVOC) emitted by plants play an important role for ecological and physiological processes, for example as response to stressors. These emitted compounds are involved in chemical processes within the atmosphere and contribute to the formation of aerosols and ozone. Direct measurement of BVOC emissions requires a specialized sample system in order to obtain repeatable and comparable results. These systems need to be constructed carefully since BVOC measurements may be disturbed by several side effects, e.g., due to wrong material selection and lacking system stability.ResultsIn order to assess BVOC emission rates, a four plant chamber system was constructed, implemented and throughout evaluated by synthetic tests and in two case studies on 3-year-old sweet chestnut seedlings. Synthetic system test showed a stable sampling with good repeatability and low memory effects. The first case study demonstrated the capability of the system to screen multiple trees within a few days and revealed three different emission patterns of sweet chestnut trees. The second case study comprised an application of drought stress on two seedlings compared to two in parallel assessed seedlings of a control. Here, a clear reduction of BVOC emissions during drought stress was observed.ConclusionThe developed system allows assessing BVOC as well as CO2 and water vapor gas exchange of four tree specimens automatically and in parallel with repeatable results. A canopy volume of 30 l can be investigated, which constitutes in case of tree seedlings the whole canopy. Longer lasting experiments of e.g., 1–3 weeks can be performed easily without any significant plant interference.Electronic supplementary materialThe online version of this article (doi:10.1186/s13007-017-0166-6) contains supplementary material, which is available to authorized users.

Responses of Contrasting Tree Functional Types to Air Warming and Drought

“…It is considered to be a drought tolerant species. Thus, being anisohydric, it keeps stomata open under drought conditions [42]. Sessile and pedunculate oak (Quercus petrea (Matt.)…”

Biogenic isoprenoid emissions under drought stress: Different responses for isoprene and terpenes

“…The onset of emission reduction with decreasing SWA% sets in even earlier compared to MTs (Rombach, 2018), as indicated by the different slopes in Fig. 3 and in Eqs.…”

“…2). For example, in the case of European beech (Fagus sylvestris) the dominant MT sabinene (Moukhtar et al, 2006) declines drastically with reduced water availability, but limonene to a smaller extend, whereas trans--ocimene stays constant within the uncertainty limit (Rombach, 2018 the overall behavior of MT emission and propose the storage pools to determine the total amount of emissions. If so, any damage to cell walls or other plant structure elements, and extensive drought length will cause a) a significant decline in total emissions beyond the drought period on the long term, and b) the ability of the plant structure to recover, to form and store new MT as before.…”

Quantification of monoterpene emission sources of a conifer species in response to experimental drought

“…In each replication four whole tree canopies were installed into a system with four dynamic plant chambers for gas exchange assessment called Tree DEMON (tree drought emission monitor) (see Lüpke et al 2016 ; Lüpke et al 2017 ). The plant chambers (~30 L volume) were made of transparent PVDF (polyvinylidene fluoride with ~97 % photosynthetically active radiation (PAR) transmissibility) mounted on a stainless steel flange.…”

“…S1 photo of the Tree DEMON]. This technique generated sufficient air mixing of the chamber volume with slight overpressure to avoid air leaking in and generated steady-state conditions (see also Lüpke et al 2017 for a detailed technical evaluation).…”