质外体是木质部外方物质运动的一个重要途径，例如物质穿过根冠。

It is an important pathway for movement of these substances outside the xylem, for example across the root cortex.

youdao

质外体是木质部外方物质运动的一个重要途径，例如物质穿过根冠。

It is an important pathway for movement of these substances outside the xylem, for example across the root cortex.

youdao