A recent article in Annals of Botany, "Arabidopsis thaliana root elongation growth is sensitive to lunisolar tidal acceleration and may also be weakly correlated with geomagnetic variations," found relations between the coincidence of root elongation rates, tides, and Earth's magnetic fields, especially those influenced by magnetic storms. The researchers grew Arabidopsis seedlings in growth chambers at constant lighting and temperature, which would be two other regulators of plant growth. At the same time, they collected information about the strength of tidal forces, or the influence of the moon and Earth's tides on gravitation, along with information about changes in the local magnetic fields, largely due to magnetic storms. The figure at the bottom of the post shows root elongation rate in black, gravimetric tide in blue, and the strongest magnetic data is orange (Polar Cap Index). In some time intervals, root elongation rate does seem to coincide with the tide. However, the paper does not say if the seeds were also germinated in the growth chambers without the influence of daily light regimes that could set a daily rhythm in the plants, which does seem to be the case here as the root elongation rates peak with 24 hour lengths. If roots do oscillate in growth chambers that limit the influence of light and temperature, and these oscillations coincide with gravimetric and magnetic fields, then roots must have previously unknown abilities of perception. The paper documents other research that suggest these abilities are plausible. The research warrants further watch.
|Figure from Annals of Botany, cited above.|