中文摘要：

生长素参与植物生长发育的各个阶段，如胚胎发生、发育，营养器官发生与形态建成，极性与轴向的建立，维管组织分化，生殖器官的发育等。虽然生长素在植物的各组织器官和细胞中发挥着重要的作用，植物内源生长素的生物合成却是在特异的组织一一细胞快速分裂的幼嫩组织中完成的，然后通过韧皮部或受严格控制的细胞一细胞运输系统运送至植物各个部分。生长素的极性运输导致其积累在某些局部组织和细胞内，形成特定梯度分布。生长素对植物生长发育众多方面的调节正是依赖于这一特性。该文综述了近年来有关植物生长发育过程中生长素浓度梯度的形成和相应的生理功能，以及细胞骨架中的微丝参与调控生长素极性运输的研究工作。

英文摘要：

Small molecular auxin is one of the most important plant hormones that have been well investigated. Auxin is believed to regulate plant organogenesis, establishment of cell polarity and axis, meristem maintenance, tissue differentiation, as well as tropic growth triggered by light or gravity. It is involved in almost every vital process during plant growth and development. Endogenous auxin is often distributed asymmetrically throughout the plant, accumulated in certain tissues and cells. The formation of these auxin gradients is due to a unique property of auxin： the directional intercellular transport. This review focuses on physiological function and formation of the auxin gradient, as well as the role of actin filaments （MFs） in regulating polar auxin transport.