Abstract
Circumnutation movements of Phaseolus vulgaris "Kentucky Wonder" are inhibited by either of the two bacterial pathogens Xanthomonas campestris pv. Phaseoli or Corynebacterium flaccumfaciens . Pattern of the horizontal trajectory and speed of the shoot tip are influenced by length of the free-moving shoot. In infected plants, length of the shoot is often reduced, along with the speed of the tip. However, when shoots of healthy and infected plants are of equal length, speed is slower in infected plants. Results from these studies suggest that effects of the two bacterial pathogens on circumnutation movements of bean shoots involve more than a reduction in shoot length.