Lee J S, Mulkey T J, Evans M L
Department of Botany, Ohio State University, Columbus 43210, USA.
Planta. 1984;160:536-43.
Primary roots of maize (Zea mays L.) and pea (Pisum sativum L.) exhibit strong positive gravitropism. In both species, gravistimulation induces polar movement of calcium across the root tip from the upper side to the lower side. Roots of onion (Allium cepa L.) are not responsive to gravity and gravistimulation induces little or no polar movement of calcium across the root tip. Treatment of maize or pea roots with inhibitors of auxin transport (morphactin, naphthylphthalamic acid, 2,3,5-triiodobenzoic acid) prevents both gravitropism and gravity-induced polar movement of calcium across the root tip. The results indicate that calcium movement and auxin movement are closely linked in roots and that gravity-induced redistribution of calcium across the root cap may play an important role in the development of gravitropic curvature.
玉米（Zea mays L.）和豌豆（Pisum sativum L.）的初生根表现出强烈的正向重力性。在这两个物种中，重力刺激均会诱导钙在根尖从上部向下部进行极性运输。洋葱（Allium cepa L.）的根对重力无响应，重力刺激在根尖几乎不会诱导钙的极性运输或根本不会诱导。用生长素运输抑制剂（整形素、萘基邻氨甲酰苯甲酸、2,3,5-三碘苯甲酸）处理玉米或豌豆根，会同时阻止重力性和重力诱导的钙在根尖的极性运输。结果表明，根中钙的运输和生长素的运输紧密相连，并且重力诱导的钙在根冠中的重新分布可能在重力性弯曲的形成中起重要作用。
