Lateral root development and gravitropism are regulated by polar auxin transport (PAT), and auxin efflux inhibitors (AEI) inhibit LR growth and tropism.

• 生长素极性运输 (polar auxin transport, PAT) 对侧根发生和根尖向地性起着重要的调节作用，添加外源生长素极性运输抑制剂不仅抑制了侧根发生，同时还使根尖丧失了向地性。