# Explain why a plant wilts when the soil around its roots dries out, referring to the roles of root hair cells and guard cells in your answer.

> Edexcel GCSE Biology (1BI0) — 6.2 Transport in plants · Explain · 4 marks

> During a prolonged dry spell, the soil around a potted plant loses most of its water. Within a few days the plant's leaves and stem begin to droop.

## Mark scheme (4 marks)

1. Root hair cells can no longer absorb water from the dry soil, so less water enters the plant
2. Water is still lost from leaves by transpiration, so the plant loses more water than it gains
3. Guard cells lose water and become flaccid, causing stomata to close (to reduce further water loss)
4. Cells throughout the plant lose water / become flaccid, reducing turgor pressure, so the plant wilts / droops

## Key terms

- [root hair cells](https://www.gradenine.co.uk/glossary/root-hair-cells)
- [guard cells](https://www.gradenine.co.uk/glossary/guard-cells)

## Related

- [Revision notes for Edexcel GCSE Biology (1BI0)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

---
Source: [GradeNine](https://www.gradenine.co.uk/q/explain-why-a-plant-wilts-when-948c2edc) · Published by Druglandscape Ltd.