Leaf voltage differences induced by fluctuating light: a proxy for the electron transport?

Light induced voltage changes in leaves can provide information on plant physiological mechanisms. Nevertheless, available articles mostly related these electrical responses to the propagation of signals in terms of plant communication. Here instead we investigate the physical and biochemical processes involved in the generation of leaf electric potentials induced by light fluctuations. The aim of this study is to correlate these voltage differences with the photosynthetic electron transport, as a new direct method for carbon assimilation measurements of several plant organs and to unravel plant interactions with the natural environment. By inserting recording electrodes in different leaves of several higher plants, we found consistent short-term responses for all plants analysed and most likely correlated to the light phase of photosynthesis. This was confirmed by applying a specific inhibitor of the electron transport (DCMU) and by inducing fast fluctuations of light since electron transport is known to operate in this fast time scales. Once validated, this method will allow simultaneous carbon assimilation measurements of several plants and organs interacting with each other.