Wired Beneath, Scented Above: A Dual-Parameter Approach to Soil-Plant Interaction via Electrical Resistance and VOC Analysis

Plants, being sessile organisms, have evolved a variety of defense mechanisms to protect themselves from invaders such as pathogens, insects, and herbivores. One key strategy is the release of volatile organic compounds (VOCs) into the air, which serve as warning signals to nearby plants, prompting them to activate their own defense mechanisms. Although plant communication through VOCs is well-documented, the interaction between VOC emissions and soil-released allelochemicals remains less understood. In this study, we investigated the relationship between the release of allelochemicals and VOCs by chickpea (gram) plants, focusing on their role in plant signalling. We grew 25 chickpea plants in individual beakers with soil as the growth medium. The release of allelochemicals was monitored indirectly by measuring the electrical resistance of the soil, while VOC emissions were analyzed using MQ-3 gas sensors. Continuous monitoring provided insights into soil chemistry changes potentially influenced by allelochemical release, alongside the VOC profile captured by the sensors. Spearman correlation analysis was applied to evaluate the relationship between allelochemical release and VOC emissions. Understanding this interplay could contribute to the development of sensor networks for early detection of plant stress, offering a potential strategy for reducing crop losses and improving agricultural resilience.