Experimental learning on plant-leaf anatomy through electrical conductivity: a multidisciplinary educational inquiry into bio-batteries

Abstract This study investigates the electrical conductivity of plant materials as a multidisciplinary educational tool, focusing on the potential of bio-batteries derived from fruits and vegetables. By examining the midrib, veins, lamina, and petiole of radish leaves, the research uncovers key relationships between leaf morphology, nutrient distribution, and electrical resistance. Experimental results reveal an inverse correlation between electrode distance and conductivity, with resistance values increasing from 17 kΩ at 1 cm to 120 kΩ at 6 cm along the midrib. Similar trends were observed in fruits and vegetables, where electrical resistance ranged from 15 Ω (onion) to 150 Ω (ladyfinger). Open circuit voltage measurements highlight significant variation, with Indian gooseberry achieving 0.966 V, onion 0.8 V, and lemon 0.9 V. Compact slices (2 cm × 1 cm × 0.5 cm) of onion stacked in series produced a cumulative output of 3.2 V, sustaining LED illumination for one hour.