Significance Because of their promotional effects on plant growth and development, rare earth elements (REEs) have been widely used in agriculture as plant growth stimulants. However, little is known about the cellular basis of REE actions in plants, and the biological safety of farm REE application in agriculture has not yet attracted enough attention. Here, we show that two types of REEs entered plant cells by endocytosis, and that they both had an activating effect on endocytosis. Moreover, we found that a portion of REEs was finally deposited in plant cells. Our data thus provide novel insights into the cellular mechanisms of REE actions in plants, and may also serve as valuable documentation for evaluating the biological safety of REE application in agriculture.