Inhibitory effects of water soluble leaf leachates from Dittrichia viscosa on lettuce root growth, statocyte development and graviperception
On a book-wide basis, the two chapters on gravitropism [30 (Pilet-relative to auxin transport) and 31 (Poovaia, Yang, and Reddy--calcium mediated)] are preceded by an excellent treatment in Chapter 3 (Sievers, Braun, and Monshausen) of the structure and function of the root cap, where much of the physical mechanism of graviperception
is discussed in detail.
Another indication that the cells use an active receptor and a physiological sensory transduction chain for graviperception
is the finding that positive gravitaxis (in young cells) can be reversed by the addition of micromolar concentrations of certain heavy metal ions (cadmium, mercury, lead).