Action potentials in the root apex are dependent on gravity.

Gravitropism plays an important role in all living organisms since they have evolved and adapted their life in a condition of constant earth’s gravity field of 1g. In this study, comparing the effect of microgravity and hypergravity treatments on plant roots electrical activity recorded in parabolic flight and in large diameter centrifuge experiments, we aims to understand better how AP’s properties are gravity dependent. Differences in spike activity were observed. Crosscorrelograms considering the electrical activity of the two main zone of the root apex, the transition and the mature zone, showed differences in the probabilities of correlated events between control experiments and gravity changed conditions ones. The decreasing of the velocity of the signal propagation - phenomenon always observed in control experiments - was much more pronounced in 0g. Spike duration was proportionally correlated to the intensity of the gravity vector. We conclude that changes in gravity conditions affect the electrical activity of plant and that APs are gravity dependent.