Leaf movements of bean plants and lunar gravity

Abstract

The hypothesis, proposed by the late Gunter Klein, that the autonomous nyctinastic movements of bean leaves are related to the tidal force exerted by the Moon was tested. Using data collected by Dr Klein, a close correspondence was found between the time at which leaves initiated a sudden downward turning movement and the time at which the tidal force changed from either a minimum (‘low tide’) or a maximum (‘high tide’). In many cases the data sets of leaf movements and the changing tidal force gave evidence of correlative patterns of behaviour. Evidence was also adduced for a minimal 6.2-h interval, or multiples thereof, between successively executed leaf movements. Data from an earlier study by A Kleinhoonte were also examined and have been found to show even closer correspondences than do Klein’s data between bean leaf-movements and changing tidal forces. Thus, Klein’s hypothesis of coherence between leaf and Moon is upheld.