Phase-shift in Geotropical Oscillations - A Theoretical and Experimental Study.

Geotropically induced phase-shifts in circumnutations of Heliauthus annuus hypocotyls are studied. - Theoretical deductions from a previously developed theory for geotropical movements are made for the case of a short gravitational stimulation in different phase positions of an oscillating hypocotyl. - Experimental studies are performed to test the theoretical results. - The conclusions are drawn, that the theory mentioned can satisfactorily describe geotropically induced phase-shifts. A comparison with phase-shifts in photoperiodic systems is made.