Search for chemical substances controlling gravitropism in plant movement

从黄化的萝卜下胚轴和玉米胚芽鞘中分离重力诱导的生长抑制剂。通过理化分析确定萝卜和玉米中的抑制剂分别为3，6 ′-二辛酰蔗糖（DSS）和2，4-二羟基-7-甲氧基-1，4-苯并恶嗪-3-酮（DIMBOA）。萝卜和玉米黄化苗水平放置时，萝卜下胚轴和玉米胚芽鞘上半部的DSS和DIMBOA含量分别迅速增加。将DSS和DIMBOA分别施于萝卜下胚轴和玉米胚芽鞘，均使其向施药部位发生弯曲。这一发现表明，向地性刺激抑制生长速率在上部的黄化萝卜下胚轴和玉米胚芽鞘的上半部，通过增加DSS和丁布的内容，引起向地性曲率。

Gravity-induced growth inhibitors were isolated from etiolated radish hypocotyls and maize coleoptiles. The radish-derived and maize-derived inhibitors were determined to be 3,6'-disinapoylsucrose (DSS) and 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA) by physicochemical analyses, respectively. When etiolated radish and maize seedlings were placed horizontally, the contents of DSS and DIMBOA rapidly increased in the upper halves of the radish hypocotyls and the maize coleoptiles, respectively. Unilateral application of DSS to the radish hypocotyls and DIMBOA to the maize coleoptiles caused both of them to bend toward the sites of application. This finding suggests that gravitropic stimulation suppresses the growth rates at the upper sides of etiolated radish hypocotyls and maize coleoptiles by increasing the contents of DSS and DIMBOA in the upper halves, causing gravitropic curvature.