A wireless leaf movement sensor system for early detection of abiotic stresses in Zea mays L

Abiotic stresses are detrimental factors for germination, organ development, and other growth activities in maize, which could reduce yield and quality. The analysis of leaf movement is a simple and efficient method to identify stresses as early as possible. This study developed a wireless leaf movement sensor system (WLMS) using a digital inertial measurement unit (IMU) to measure maize leaf movement in real-time and detect abiotic stresses quickly.

The IMU was designed as a lightweight sensor structure that the IMU was separated from the MCU (microcontroller unit) and connected via flexible cables. This lightweight sensor attached to maize leaves easily and measured leaf movement in real-time with high resolution (measured error of ± 0.25°). The IMU collected leaf movement data and transmitted the data wirelessly to the data receiving terminal (host computer). Meanwhile, the data receiving terminal performed linear fitting on the daily leaf movement data to extract the movement characteristics of maize leaves. The WLMS detected abiotic stress in maize based on the leaf movement characteristics under different stress conditions. The results indicated that the WLMS could detect whether maize was under stress within one day of being stressed and identify the specific type of stress within the following 5-7 days, providing a lead time of 2 days compared to other non-destructive methods (including RGB imaging, hyperspectral analysis, and chlorophyll meters).

This sensor system enables the rapid and early detection and identification of abiotic stresses in maize as a low-cost tool for plant phenotype measurement and plant movement measurement.