Browsing by Subject "Gravimetry"

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Chamber‐based system for measuring whole‐plant transpiration dynamics
(2022) Pieters, Alejandro; Giese, Marcus; Schmierer, Marc; Johnson, Kristian; Asch, Folkard
Most of our insights on whole‐plant transpiration (E) are based on leaf‐chamber measurements using water vapor porometers, IRGAs, or flux measurements. Gravimetric methods are integrative, accurate, and a clear differentiation between evaporation and E can be made. Water vapor pressure deficit (VPD) is the driving force for E but assessing its impact has been evasive, due to confounding effects of other climate drivers. We developed a chamber‐based gravimetric method, in which whole plant response of E to VPD could be assessed, while keeping other environmental parameters at predetermined values. Stable VPD values (0.5–3.7 kPa) were attained within 5 min after changing flow settings and maintained for at least 45 min. Species differing in life form and photosynthetic metabolism were used. Typical runs covering the range of VPDs lasted up to 4 h, preventing acclimation responses or soilborne water deficit. Species‐specific responses of E to VPD could be identified, as well as differences in leaf conductance. The combined gravimetric‐chamber‐based system presented overcomes several limitations of previous gravimetric set ups in terms of replicability, time, and elucidation of the impact of specific environmental drivers on E, filling a methodological gap and widening our phenotyping capabilities.
Measurement of the reaction enthalpy of CO₂ in aqueous solutions with thermographic and gravimetric methods
(2024) Jung-Fittkau, Jessica; Diebold, Josef; Kruse, Andrea; Deigner, Hans-Peter; Schmidt, Magnus S.; Jung-Fittkau, Jessica; Organic and Bioorganic Chemistry Labs, Medical and Life Sciences Faculty, Institute of Precision Medicine, Furtwangen University, Jakob-Kienzle-Str. 17, 78054, Villingen-Schwenningen, Germany; Diebold, Josef; Organic and Bioorganic Chemistry Labs, Medical and Life Sciences Faculty, Institute of Precision Medicine, Furtwangen University, Jakob-Kienzle-Str. 17, 78054, Villingen-Schwenningen, Germany; Kruse, Andrea; Institute of Agricultural Technology, University of Hohenheim, Schloß Hohenheim 1, 70599, Stuttgart, Germany; Deigner, Hans-Peter; Organic and Bioorganic Chemistry Labs, Medical and Life Sciences Faculty, Institute of Precision Medicine, Furtwangen University, Jakob-Kienzle-Str. 17, 78054, Villingen-Schwenningen, Germany; Schmidt, Magnus S.; Organic and Bioorganic Chemistry Labs, Medical and Life Sciences Faculty, Institute of Precision Medicine, Furtwangen University, Jakob-Kienzle-Str. 17, 78054, Villingen-Schwenningen, Germany
In this work, a new concept for the approximate determination of the reaction enthalpy of the reaction between CO2 and monoethanolamine (MEA) in aqueous solution was developed. For this purpose, a CO2 gas stream was flowed into aqueous MEA solutions with different concentrations of 1 wt%, 2.5 wt% and 7.5 wt%. The weight difference ∆T, which is based on the increase in CO2 bound by the MEA over time, was documented using a thermographic camera. The mass difference ∆m, which is also based on the increase in CO2 bound by the MEA over time, was determined using a balance. By determining ∆T and ∆m, an approximate calculation of the reaction enthalpy is possible. The deviation from the values from the data known from the literature was less than 5% in all experiments.