Fondren W M, Moore R
Department of Biology, Baylor University, Waco, TX 76798, USA.
Ann Bot. 1987;59:657-9. doi: 10.1093/oxfordjournals.aob.a087363.
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).
我们将琼脂块放置在电刺激的玉米初生根根尖附近。在根的阳极侧附近放置3小时的琼脂块，随后不对称地放置在垂直根的根尖上时，会诱导出明显的弯曲。弯曲总是朝向放置琼脂块的根的一侧。未接触根的琼脂块以及放置在电刺激根的阴极侧附近的琼脂块，不对称地放置在垂直根的根尖上时，不会诱导出明显的弯曲。原子吸收分光光度法表明，与电刺激根的阳极侧相邻的琼脂块所含钙量明显多于：（1）未接触根的琼脂块，以及（2）接触根的阴极侧的琼脂块。这些结果表明，在电刺激根（即经历类似向重力性弯曲的根）的黏液中存在内源性钙梯度。
