title: Non-invasive determination of plant biomass with microwave resonators.
abstract: Non-invasive and rapid determination of plant biomass would be beneficial for a number of research aims. Here, we present a novel device to non-invasively determine plant water content as a proxy for plant biomass. It is based on changes of dielectric properties inside a microwave cavity resonator induced by inserted plant material. The water content of inserted shoots leads to a discrete shift in the centre frequency of the resonator. Calibration measurements with pure water showed good spatial homogeneity in the detection volume of the microwave resonators and clear correlations between water content and centre frequency shift. For cut tomato and tobacco shoots, linear correlations between fresh weight and centre frequency shift were established. These correlations were used to continuously monitor diel growth patterns of intact plants and to determine biomass increase over several days. Interferences from soil and root water were excluded by shielding pots with copper. The presented proof of principle shows that microwave resonators are promising tools to quantitatively detect the water content of plants and to determine plant biomass. As the method is non-invasive, integrative and fast, it provides the opportunity for detailed, dynamic analyses of plant growth, water status and phenotype.
authors.affiliation: ICG-3 (Phytosphere), Forschungszentrum Jülich, Jülich, Germany.
authors.forename: Marion I
authors.initials: MI
authors.lastname: Menzel
authors.forename: Susanne
authors.initials: S
authors.lastname: Tittmann
authors.forename: Jonas
authors.initials: J
authors.lastname: Bühler
authors.forename: Stella
authors.initials: S
authors.lastname: Preis
authors.forename: Norbert
authors.initials: N
authors.lastname: Wolters
authors.forename: Siegfried
authors.initials: S
authors.lastname: Jahnke
authors.forename: Achim
authors.initials: A
authors.lastname: Walter
authors.forename: Antonia
authors.initials: A
authors.lastname: Chlubek
authors.forename: Ariel
authors.initials: A
authors.lastname: Leon
authors.forename: Normen
authors.initials: N
authors.lastname: Hermes
authors.forename: Andreas
authors.initials: A
authors.lastname: Offenhäuser
authors.forename: Frank
authors.initials: F
authors.lastname: Gilmer
authors.forename: Peter
authors.initials: P
authors.lastname: Blümler
authors.forename: Ulrich
authors.initials: U
authors.lastname: Schurr
authors.forename: Hans-Joachim
authors.initials: HJ
authors.lastname: Krause
mesh_terms: D018533:Biomass; D008872:Microwaves; D063245:Plant Development; D018520:Plant Shoots / Q000737:chemistry; D010944:Plants / Q000737:chemistry*; D014867:Water / Q000032:analysis*
chemical_list: D014867:Water