pith parenchyma

例句：

1. 1. The tree's trunk is made up of a combination of wood and pith parenchyma.
   这棵树的树干由木材和木质部组成。
2. 2.The roots are composed of cortex and pith parenchyma.
   根由木栓层和木质部组成。
3. 3.The pith parenchyma is responsible for the tree's ability to absorb water and nutrients.
   木质部负责树木吸收水分和养分的能力。