---
title: "Transpiration and Transport in Plants"
description: "Water pulled up the xylem replaces what evaporates from the leaves, while phloem carries dissolved sugar to where it is used or stored. Covers stomata, guard cells, and what changes the transpiration "
canonical: https://lightmysky.com/learn/science/transpiration-and-transport-in-plants-mt_AqN0vL8QRu
source: https://lightmysky.com/learn/science/transpiration-and-transport-in-plants-mt_AqN0vL8QRu.md
retrieved: 2026-09-12
---

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# Transpiration and Transport in Plants

Water pulled up the xylem replaces what evaporates from the leaves, while phloem carries dissolved sugar to where it is used or stored. Covers stomata, guard cells, and what changes the transpiration rate.

Subject: Science · Area: Organisms & Life Processes · Ages 15 to 16
Page: https://lightmysky.com/learn/science/transpiration-and-transport-in-plants-mt_AqN0vL8QRu

## Ready when they can

- Says what xylem carries and what phloem carries, and in which direction each one moves it.
- Predicts the effect of higher temperature, wind or humidity on transpiration rate.
- Explains why closing the stomata saves water and costs photosynthesis.

## Lesson: Thirsty leaves, busy pipes

Roots absorb water, xylem pipes it upward, and leaves evaporate it away. Losing water on top tugs the whole column higher, and dissolved minerals ride along free. Sugar made in leaves travels separately: phloem carries it down to roots and fruits.

Leaves trade water for food through pores called stomata. Open pores admit carbon dioxide but leak vapour, and guard cells swell them shut in drought. Waxy skins and needle shapes ration loss further. Closing saves water but starves photosynthesis.

**Example.** Heat, wind and dry air speed transpiration, while humidity and still air slow it. Roots play their part too: hairs balloon the surface area, thin walls ease entry, and vessels collect the flow.

**Tip.** Every opening is a deal: food in, water out. Compare species by counting stomata under a microscope. The hungrier the leaf, the thirstier it must be.

**Recap.** Xylem lifts water to the deal, stomata open it, and guards close it when the price in water runs too high.

## Practice

8 questions on this page, each with its working shown.

## Needs first

- [The Water Cycle in Detail](https://lightmysky.com/learn/science/the-water-cycle-in-detail-mt_V2lNzEex_a)

## Opens up

- [Cohesion-Tension and Water Movement in the Xylem](https://lightmysky.com/learn/science/cohesion-tension-and-water-movement-in-the-xylem-mt_9_TORolYIl)
- [Plant Growth Responses: Tropisms and the Hormones Behind Them](https://lightmysky.com/learn/science/plant-growth-responses-tropisms-and-the-hormones-behind-them-mt_q1N7OG2_6j)