Disseration Marvin_Lüpke

s and contributions to the individual publications -294 Abstracts and contributions to the individual publications 4.1 The Tree Drought Emission MONitor (Tree DEMON), an innovative system for assessing biogenic volatile organic compounds emission from plants Marvin Lüpke, Rainer Steinbrecher, Michael Leuchner and Annette Menzel (2017): Plant Methods 13:14; doi: 10.1186/s13007-017-0166-6. (Lüpke et al. 2017b) Background: Biogenic 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. Results: In 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. Conclusion: The 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. Contributions: I did the finalized design/construction/programming of the Tree DEMON and performed system test shown in this publication. Rainer Steinbrecher provided support for the system and its evaluation, Michael Leuchner and Annette Menzel provided methodological support. All co-authors reviewed and improved the draft manuscript before submission. About 85% of the work was done by myself. Abstracts and contributions to the individual publicationss and contributions to the individual publications -304.2 Impact of summer drought on isoprenoid emissions and carbon sink of three Scots pine provenances Marvin Lüpke, Michael Leuchner, Rainer Steinbrecher and Annette Menzel (2016): Tree Physiology 36: 1382–1399, doi: 10.1093/treephys/tpw066. (Lüpke et al. 2016) Scots pine (Pinus sylvestris L.) provenances cover broad ecological amplitudes. In a greenhouse study, we investigated the impact of drought stress and rewetting on gas exchange for three provenances (Italy: Emilia Romagna; Spain: Alto Ebro; Germany: East-German lowlands) of 2-year old Scots pine seedlings. CO2, water vapor and isoprenoid exchange of stressed and control trees were quantified with a four-chamber dynamic-enclosure system in the controlled environment of a climate chamber. The three provenances showed distinct isoprenoid emission patterns and were classified into a non-Δ-carene, with either high α-/β-pinene or β-myrcene fraction, and a Δ-carene dominated type. Isoprenoid emission rates, net-photosynthesis and transpiration were reduced during summer drought stress and significantly recovered after rewetting. A seasonal increase of isoprenoid emission rates towards autumn was observed for all control groups. Compared with the German provenance, the Spanish and Italian provenances revealed higher isoprenoid emission rates and more plastic responses to drought stress and seasonal development, which points to a local adaptation to climate. As a result of drought, net carbon uptake and transpiration of trees was reduced, but recovered after rewetting. We conclude from our study that Scots pine isoprenoid emission is more variable than expected and sensitive to drought periods, likely impacting regional air chemistry. Thus, a provenancespecific emission assessment accounting for reduced emission during prolonged (summer) drought is recommend for setting up biogenic volatile organic compound emission inventories used in air quality models. Contributions: I had the idea for and designed the study. Michael Leuchner and Rainer Steinbrecher provided methodological support and supported me together with Annette Menzel in data analysis and writing of the manuscript. All co-authors reviewed the draft manuscript before submission. About 80% of the work was done by myself. Abstracts and contributions to the individual publicationss and contributions to the individual publications -314.3 Quantification of monoterpene emission sources of a conifer species in response to experimental drought Marvin Lüpke, Rainer Steinbrecher, Michael Leuchner and Annette Menzel (2017): re-submission currently under review in AOB Plants (Lüpke et al. 2017a) – resubmitted at 05.08. 2017 Monoterpene emissions of conifer tree species, emitted from de novo synthesis and storage pools, play an important role in plant ecology and physiology. During drought stress both emission sources are affected differently and with conventional measuring techniques they are difficult to separate. We investigated C labelled monoterpene (MT) emission of eight 3-year-old Scots pine seedlings in a drought stress experiment using a dynamic gas exchange chamber system (Tree DEMON). MT, water vapor and CO2 gas exchange were measured for a 2-day normal watering, a 11-day treatment and a 3-day re-watering period. In each period all trees were C labelled once for five hours. Results showed the expected decrease of MT, water vapor and CO2 gas exchange with decreasing soil water content. However, during re-watering water vapor and CO2 gas exchange recovered fast to pre-drought levels, whereas MT increased to a lower level compared to the initial non-stressed phase. The C labelling showed highly variable %C values for different monoterpenes, which ranged compound-specific from 0.5 to 95% for unstressed trees. Overall, around 36±5% of the total emission rate originated from de novo synthesized MTs during the 2-day prior to stress period. During full drought, the de novo fraction was reduced to 3%. For the re-watering phase de novo emissions recovered only partly to 20%, while pool emissions reached pre-drought conditions. Thus, emissions of de novo synthesized MTs of Scots pine are down regulated by soil drought rather than MT emissions from pools. Contributions: I had the idea for and designed the study. Michael Leuchner and Rainer Steinbrecher provided methodological support. Annette Menzel helped in data analysis and writing of the manuscript. All co-authors reviewed the draft of the manuscript before submission. About 80% of the work was done by myself.