Collection of gravitropic effectors from mucilage of electrotropically-stimulated roots of Zea mays L.
We placed agar blocks adjacent to tips of electrotropically stimulated primary roots of Zea mays.  Blocks placed adjacent to the anode-side of the roots for 3 h induced significant curvature when subsequently placed asymmetrically on tips of vertically-oriented roots.  Curvature was always toward the side of the root unto which the agar block was placed.  Agar blocks not contacting roots and blocks placed adjacent to the cathode-side of electrotropically stimulated roots did not induce significant curvature when placed asymmetrically on tips of vertically-oriented roots.  Atomic absorption spectrophotometry indicated that blocks adjacent to the anode-side of electrotropically-stimulated roots contained significantly more calcium than (1) blocks not contacting roots, and (2) blocks contacting the cathode-side of roots.  These results demonstrate the presence of a gradient of endogenous Ca in mucilage of electrotropically-stimulated roots (i.e. roots undergoing gravitropic-like curvature).
Fondren
W M
WM
Department of Biology, Baylor University, Waco, TX 76798, USA.
Moore
R
R
D002118:Calcium / Q000378:metabolism* / Q000502:physiology; D004558:Electric Stimulation; D004560:Electricity; D004566:Electrodes; D018522:Gravitropism / Q000502:physiology*; D018517:Plant Roots / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D018523:Tropism / Q000502:physiology*; D003313:Zea mays / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*
D002118:Calcium