The redistribution of reducing power in the elongating zone of geostimulated bean roots
Juniper BE., Owens RJ., Whale D., Shaw AC.
Beans (Vicia faba) were grown in darkness until their roots were 20-40 mm in length. Still in the dark they were then placed horizontally and after specific times the terminal 20 mm of the roots was excised, bisected in a plane at right angles to the direction of gravity and the (new) upper and lower half segments were analysed for reducing power by the dichlorophenolindophenol method. At approximately three hours after having been placed in the horizontal position there was a marked decrease of approx. 20% of the reducing power in the upper half segment of the root followed by an equally rapid return to equivalence. The time of this loss corresponds closely with the maximum period of the bending. If the horizontal roots were not bisected and then compared to bisected tips there was no significant difference in total reducing power. This suggests that the loss of reducing power in the upper half was not due to 'leakage' as a result of the surgery. © 1980.