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.

Breeding for improved drought tolerance in Chickpea (Cicer arietinum L.)

“…Plant phenotyping is exclusive evaluation of plant physiology, growth, development, resistance, tolerance, architecture, yield, ecology and quantitative traits. Biomass (Menzel et al 2009), root morphology (Clark et al 2011), leaf traits (Arvidsson et al 2011), fruit traits (Monforte et al 2014), yield and its components (Duan et al 2011), photosynthetic efficiency (Bauriegel et al 2011), and responsiveness to abiotic and biotic stresses (Balachandran et al 1997, Rao andLaxman 2013) are the important plant traits which can be measured by phenotyping tools. Scoring of disease symptoms and visual plant selection by breeders are the main areas where phenotyping is being used.…”

The reflectivity in the S‐band and the broadband ultrasonic spectroscopy as new tools for the study of water relations in Vitis vinifera L.

“…Martínez et al () described a time domain reflectometry method to estimate leaf disk water status by measuring reflectivity on the X‐band (7–12 GHz) with a non‐portable laboratory equipment. More recently, Menzel et al () proposed a non‐invasive technique for measuring the changes in the dielectric properties of a whole plant when introduced in a microwave cavity resonator. In spite of the good results obtained by Martínez et al () and Menzel et al (), the complexity of the experimental setup and the low portability prevented the applicability of such methods for the development of practical tools to characterize plant water status under field conditions so far.…”

“…More recently, Menzel et al () proposed a non‐invasive technique for measuring the changes in the dielectric properties of a whole plant when introduced in a microwave cavity resonator. In spite of the good results obtained by Martínez et al () and Menzel et al (), the complexity of the experimental setup and the low portability prevented the applicability of such methods for the development of practical tools to characterize plant water status under field conditions so far. More recently, Sancho‐Knapik et al () used a microwave digital cordless telephony patch antenna to measure the reflectivity at a frequency of 1730 MHz (L‐band).…”

Espectroscopía Ultrasónica Resonante Sin Contacto y su Aplicación al Estudio de Tejidos Vegetales en Estructura Multicapa = Non-Contact Resonant Ultrasound Spectroscopy and its Application to Study Multilayered Vegetal Tissues

“…Martínez et al (1995 described a time domain reflectometry method to estimate leaf disk water status by measuring reflectivity on the X-band (7)(8)(9)(10)(11)(12) with a non-portable laboratory equipment. More recently, Menzel et al (2009) proposed a non-invasive technique for measuring the changes in the dielectric properties of a whole plant when introduced in a microwave cavity resonator. In spite of the good results obtained by Martínez et al (1995) and Menzel et al (2009), the complexity of the experimental setup and the low portability prevented the applicability of such methods for the development of practical tools to characterize plant water status under field conditions so far.…”

“…More recently, Menzel et al (2009) proposed a non-invasive technique for measuring the changes in the dielectric properties of a whole plant when introduced in a microwave cavity resonator. In spite of the good results obtained by Martínez et al (1995) and Menzel et al (2009), the complexity of the experimental setup and the low portability prevented the applicability of such methods for the development of practical tools to characterize plant water status under field conditions so far. More recently, SanchoKnapik et al (2011a) used a microwave digital cordless telephony patch antenna to measure the reflectivity at a frequency of 1730 MHz (L-band).…”