Plant growth in response to three types of electrode assemblies in the soil around chickpea plants. From left to right, C represents control with no voltage, SC indicates Short Circuit, OC is for Open Circuit and CC is Closed Circuit. Credit: S. Venkata Mohan
Bioengineers have shown that low voltage generated in the soil around plant roots can be harnessed to stimulate growth in mung bean and chickpea plants1.
Soil microbes interact with plant roots to generate low voltage. Specific electrodes planted in the soil convert the voltage into a low current that acts as a stimulus for plant growth by boosting metabolic processes, including photosynthesis.
This method could become a viable option for sustainable agriculture, says a team at the CSIR-Indian Institute of Chemical Technology in Hyderabad.
To test the method, the scientists placed three types of electrode assemblies in the soil around mung bean and chickpea plants.
The team, which included S. Venkata Mohan, found that the low current generated by the electrodes increased plant height, leaf area, flowering, weight, and chlorophyll content in both plants. It also shortened the time it took the plants to go from their vegetative to reproductive phase.
Another finding was that levels of proline – a stress metabolite in roots and leaves – shot up. This suggests that the electrical stimulus could enhance the plants’ capacity for tolerating stress.
Besides causing changes in gene expression patterns, it induced an abundance of aquaporins – transmembrane channel proteins – which help water and solute transport in plant cells. This method could potentially be used to remove pollutants from contaminated soil, says Venkata Mohan.
