Methodology: non-invasive monitoring system based on standing wave ratio for detecting water content variations in plants

Abstract

Background Water content variation during plant growth is one of the most important monitoring parameters in plant studies. Conventional parameters (such as dry weight) are unreliable; thus, the development of rapid, accurate methods that will allow the monitoring of water content variation in live plants is necessary. In this study, we aimed to develop a non-invasive, radiofrequency-based monitoring system to rapidly and accurately detect water content variation in live plants. The changes in standing wave ratio (SWR) caused by the presence of stem water and magnetic particles in the stem water flow were used as the basis of plant monitoring systems. Results The SWR of a coil probe was used to develop a non-invasive monitoring system to detect water content variation in live plants. When water was added to the live experimental plants with or without illumination under drought conditions, noticeable SWR changes at various frequencies were observed. When a fixed frequency (1.611 GHz) was applied to a single experimental plant (Radermachera sinica), a more comprehensive monitoring, such as water content variation within the plant and the effect of illumination on water content, was achieved. Conclusions Our study demonstrated that the SWR of a coil probe could be used as a real-time, non-invasive, non-destructive parameter for detecting water content variation and practical vital activity in live plants. Our non-invasive monitoring method based on SWR may also be applied to various plant studies.

Using Consensus Land Cover Data to Model Global Invasive Tree Species Distributions

“…Thus, there is a reasonable explanation for the results of the present study. Previous research has shown that the number of occurrence records can have a strongly negative impact on Maxent’s simulated distribution of invasive species [ 38 ]. In this paper, the occurrence records of P. pinaster reached 250,000.…”

“…As is widely known, water changes during plant growth are among the most important monitoring parameters in plant research [ 39 ]. Open water land cover indicates that such areas provide suitable temperatures and water for organisms inhabiting the surrounding environment within a certain space and time range [ 38 , 40 , 41 ].…”

Miniature Noninvasive Sensor Based on Impedance-Change Detection in Branches for Measuring Branch Ice Content in Overwintering Woody Plants

“…The dielectric properties of plant branch tissue lie between those of polar and ionic materials, and the branch tissue is viewed as a complex porous dielectric substance consisting of a mixture of gas (g), liquid (l), and solid (s) [ 28 , 29 , 30 ], whose dielectric model can be represented by the equivalent circuit diagram, as shown in Figure 2 . The total impedance of the branch tissue is: where is the total impedance of the branch tissue; , , , , and correspond to the resistance and capacitance of gas, liquid, and solid substances, respectively; and the expression for the relative permittivity of a capacitor is: where is determined by the geometry of the measuring electrode, is the vacuum permittivity ( ), is the relative permittivity, and is the capacitance.…”

Freeze-thaw Assessment of Plants Based on Envelope Analysis of Stem Volume Water Content Sequence

“…When 100 MHz electromagnetic wave generated by the signal source is transmitted along a coaxial transmission line, the impedance of the ring probe installed at the stem does not match the impedance of the transmission line. The electromagnetic wave will be re ected when transmitted to the probe; and then the incident and the re ected waves on the transmission line will be superimposed to form a standing wave [28,29]. The peak and trough values of the standing wave signal are measured at both ends of the transmission line and the difference between the peak and trough values is calculated (Eq.…”