United States Department of Agriculture, Agricultural Research Service, Agricultural Research Center-West, Beltsville, Maryland 20705.
Plant Physiol. 1987 Jan;83(1):195-8. doi: 10.1104/pp.83.1.195.
Brassinosteroids are steroidal lactones of plant origin that promote growth of a number of plant systems, and particularly the growth induced by auxins. Biologically active brassinosteroids (BR) also promote the growth of gravisensitive hypocotyls of 7-day-old light grown Phaseolus vulgaris when gravistimulated. Brassinolide-mediated promotion of curvature of gravistimulated internodes occurs in the absence of exogenously supplied indole-3-acetic acid (IAA). This is in contrast to the BR-promoted bending of vertically positioned bean hypocotyls, which is dependent upon exogenous IAA. Brassinosteroid treatment increased the graviperception of young internode tissues and the bending of the gravistimulated sections as well as the subsequent reversal of bending after the sections were placed vertically. These results indicate that BR sensitizes bean hypocotyls to gravistimulation and potentiates the action of a growth factor that induces gravitropic growth.
油菜素内酯是植物来源的甾体内酯，可促进许多植物系统的生长，特别是促进生长素诱导的生长。生物活性油菜素内酯（BR）也可促进重力刺激下生长 7 天的光培养菜豆（Phaseolus vulgaris）中重力敏感下胚轴的生长。油菜素内酯介导的重力刺激节间弯曲的发生不依赖于外源供应的吲哚-3-乙酸（IAA）。这与 BR 促进垂直放置的豆下胚轴弯曲形成对比，后者依赖于外源 IAA。油菜素内酯处理增加了年轻节间组织的重感知和重力刺激部位的弯曲，以及节段垂直放置后弯曲的后续逆转。这些结果表明，BR 使菜豆下胚轴对重力刺激敏感，并增强了诱导向重力生长的生长因子的作用。
