# Xylem

> The plant's water-conducting tissue, which carries water and dissolved mineral ions upward from roots to leaves, driven mainly by transpiration.

- Canonical: https://genetixbay.com/knowledge/glossary/xylem.html
- Also written: xylem vessels, xylem tissue, water-conducting tissue, tracheids
- Glossary category: Plant biology · Evidence: Established
- Status: Draft: awaiting expert review · Updated: 2026-10-31
- Licence: CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0/), attribute "GenetixBay cannabis glossary"

Xylem is vascular tissue made of hollow, dead, lignified cells (vessels and tracheids) that form continuous pipes from roots to leaves. Water moves up under tension created by [transpiration](https://genetixbay.com/knowledge/glossary/transpiration.md) at the leaves, carrying [nitrate](https://genetixbay.com/knowledge/glossary/nitrate.md), calcium, potassium and other ions taken up by the roots. Xylem also gives stems much of their strength; wood is mostly xylem.

## In practice

Xylem explains several growing problems:
- **Calcium and [boron](https://genetixbay.com/knowledge/glossary/boron.md)** travel almost only in the xylem, so they go where water goes. Fast new growth in humid, still air (low transpiration) can show calcium-type symptoms even with plenty in the feed.
- **Wilting** in hot, [dry rooms](https://genetixbay.com/knowledge/glossary/drying-room.md) happens when water loss beats what the roots and xylem can supply.
- **Clones**: cutting stems underwater or quickly into the rooting medium avoids air entering the xylem (embolism), which can block water flow.
- **Wilt pathogens** such as *[Fusarium oxysporum](https://genetixbay.com/knowledge/glossary/fusarium-wilt.md)* block xylem, causing wilting even in moist media.

## Don't confuse with

- **Phloem**: carries sugars and [mobile nutrients](https://genetixbay.com/knowledge/glossary/mobile-nutrient.md), both up and down.
- **Pith**: soft central tissue of the stem.
- **Cambium**: the layer that makes new xylem and [phloem](https://genetixbay.com/knowledge/glossary/phloem.md).

## Related terms

[Phloem](https://genetixbay.com/knowledge/glossary/phloem.md), [Transpiration](https://genetixbay.com/knowledge/glossary/transpiration.md), [Stomata](https://genetixbay.com/knowledge/glossary/stomata.md), [Root hair](https://genetixbay.com/knowledge/glossary/root-hair.md)

## Read more

- [Mobile vs immobile nutrients: reading old vs new leaves](https://genetixbay.com/knowledge/nutrients/mobile-vs-immobile-nutrients.md)
- [VPD explained: vapour pressure deficit for cannabis growers](https://genetixbay.com/knowledge/environment/vpd-explained.md)

## Sources

1. Taiz L, Zeiger E, Møller IM, Murphy A. 2015. Plant Physiology and Development, 6th edition. Sinauer Associates.