xylem

/zahy-luhm, -lem/US // ˈzaɪ ləm, -lɛm //UK // (ˈzaɪləm, -lɛm) //

木质部

Definitions

n.名词 noun

1
Botany.
- : a compound tissue in vascular plants that helps provide support and that conducts water and nutrients upward from the roots, consisting of tracheids, vessels, parenchyma cells, and woody fibers.

Such a feat seemed so unlikely for the tiny insects that some scientists questioned whether xylem sap truly could be under such negative pressures.
This strategy suggests that the negative pressures of xylem sap can exceed one megapascal.
Extra xylem and phloem help the stem pump more food and water into the fruit, leaving less for the rest of the plant.
Xylem, zī′lem, n. the woody part of vegetable tissue—opposed to the phlom, or bast part.
All round the xylem and the phloëm there are many thick-walled cells.
These vessels together with the numerous small thick-walled cells lying between the pitted vessels constitute the xylem.
Just above the xylem there is a group of large and small thin-walled cells.
The larger bundles are normal in every way, while in the smaller ones the xylem elements are considerably reduced.