How does the diurnal biological clock influence electrokinetics in a living plant?

Abstract

The existence of electrical potential in plant tissues has been studied for decades to understand its contribution toward the plants' health and developmental aspects. This potential is profoundly controlled and modulated by the electrokinetics involved in the flow navigated through the narrow conduits of a plant, which in turn is primarily governed by circadian rhythms. However, the interconnection between electrokinetics and the diurnal biological clock is yet to be understood. In this work, we unraveled the electrokinetics in response to the diurnal variations of a plant. Experiments conducted on water hyacinth stem indicate a cyclic variation of streaming potential synchronized with the changes introduced by circadian rhythm. In further efforts toward understanding the variation of streaming potential at different flow conditions, experiments were conducted on excised stem segments of Dracaena sanderiana, where the generated potential was studied against varying flow rates with different constitutive features of the flowing electrolyte. Notably, the resulting streaming potential from the flow of electrolytic solutions of different ionic strengths, species, and pH was found to align well with the fundamental premises of electrokinetics. These results are likely to expand our current knowledge of plant hydraulics by diligently examining the electrokinetics involved in the flow circuits of plants that undergo cyclic variations in close association with the circadian rhythms.