Flexible PI-Based Plant Drought Stress Sensor for Real-Time Monitoring System in Smart Farm

Abstract

Plant growth and development are negatively affected by a wide range of external stresses, including water deficits. Especially, plants generally reduce the stomatal aperture to decrease transpiration levels upon drought stress. Advanced technologies, such as wireless communications, the Internet of things (IoT), and smart sensors have been applied to practical smart farming and indoor planting systems to monitor plants' signals effectively. In this study, we develop a flexible polyimide (PI)-based sensor for real-time monitoring of water conditions in tobacco plants. The stoma response, by which a plant adjusts to drought stress to maintain homeostasis, can be confirmed through the examination of evaporated water. Using a flexible PI-based sensor, a plant's response variation is translated into an electrical signal. The sensors are integrated with a Bluetooth (BLE) module and a processing module and show potential as smart real-time water sensors in smart farms.

Ultraconformable, Self‐Adhering Surface Electrodes for Measuring Electrical Signals in Plants

“…[ 9,28 ] Different thin‐layer sensors and electronic systems based on materials like conductive polymers and graphene operating on the plant surface have been developed for measuring for example humidity or concentrations of certain biomolecules with great potential for agricultural monitoring. [ 29–33 ] Especially thin film electrodes based on graphene and carbon nanotubes, [ 34–36 ] silver inks [ 37 ] and silver nanowires, [ 38 ] conductive polymers, [ 29,39 ] and liquid metals [ 40 ] have shown advantages for being patternable into various shapes, bearing an excellent applicability on plant surfaces, having physiological sensing capability, and some are transparent or semitransparent. Yet, the development of techniques for recording intrinsic electrophysiological signals on plants and using them in biohybrid technologies remains limited to a few examples whereas the long‐established research on the biological aspects on plant's electrical signals started back in the 19th century by observations of electrical signals in Venus flytraps ( Dionaea muscipula ) by Sanderson.…”

A Systematic Review of IoT Solutions for Smart Farming

“…Such sensors are used for collecting real-time data about multiple agricultural parameters, such as climatic data, substrate information, luminosity, CO2 concentration and images through cameras and multispectral sensors, as shown in Table 3 . Moreover, several papers (4%) focused on developing custom-made sensors for monitoring specific agricultural aspects, such as soil nutrients (e.g., nitrate [ 158 ]) and leaf evapotranspiration for measuring the hydric stress in tobacco crops [ 81 ].…”

Flexible Wearables for Plants

“…To solve this problem, IM et al. [ 63 ] directly adhered the plant wearable to the leaf surface to avoid its damage caused by clamping and fixing. Furthermore, to increase the adhesion, one‐side sticky polyethylene terephthalate (PET) film is also added to polyimide (PI) as the base material.…”