In older stems, only the most recent rings of xylem participate in the transport of materials. these make up the sapwood.
在老茎中，仅最新的木质部环参与物质的运输。这些木质部环组成边材。
2
A system confined to the transport of mineral elements is known as the xylem.
专门用来运输矿物元素的系统称为木质部。
3
Recessive mutations in several loci of Arabidopsis were previously shown to lead to a collapsed xylem phenotype but water-transport deficiency was not observed.