The development and application of an electrical impedance spectroscopy measurement system for plant tissues

For the impedance measurement system for plant tissues, a stable current source, the magnitude of which may be affected by the capacity of the operational amplifier, loading and high-frequency noise. Hence, this application note describes the use of a second-generation current conveyor (CCII) to improve the electrical circuit, plus a voltage buffer is used to significantly reduce the loading effect. A personal computer is integrated with LabVIEW software for data collection, analysis and processing. This forms a highly-effective measurement system which improves the portability of the measurement instrument. Within the frequency range 100 Hz–1 MHz, two groups of precision resistance-capacitance are adopted: 49.98 kΩ, 1.01 nF; 49.98 kΩ, 9.8 nF to execute the measurement simulation. The results of simulation measurement show that all the errors are within 5%, and the relative standard deviation within 0.30%, and these confirm that the system is highly accurate and precise in this implementation. Carrot is chosen as the target object for practical evaluation, for which the electrical impedance spectrum is a circular arc with its circular center below the real axis. Results for carrot are presented.

► This approach develops a novel impedance measurement system for plant.
► This study employs a new current conveyor as current source to improve measurements.
► With errors below 5% and the RSD within 0.30%, accuracy and precision is approval.
► The impedance spectrum of the carrot is consistent with prediction.
► The distribution coefficient of the relaxation time of carrot is 0.86 same as others.