Annals of Botany

Leaf movements and lunisolar gravitational force

A new perspective on the regulation of leaf-movement rhythms and synchronism between the times of the turning points of both the lunisolar tide and leaftide
Leaf movements and lunisolar gravitational force
Leaf movements and lunisolar gravitational force

The concept of an endogenous ‘clock’ as a regulator of the diurnal movements of leaves of beans and other species does not completely account for the rhythms that are generated following germination in constant light or dark conditions, or when plants are transferred to similar free-running conditions. Barlow analyses published studies of leaf movements in conjunction with the contemporaneous time courses of the lunisolar tidal acceleration at the relevant experimental locations in order to develop a new perspective on the regulation of leaf-movement rhythms. In all cases, it is evident that a synchronism exists between the times of the turning points of both the lunisolar tide and of the leaftide when the direction of leaf movement changes. Two hypotheses that could account for this synchronism, based on either quantum considerations or on classical Newtonian physics, are presented and discussed.