Transpiration and Translocation

Syllabus tag: KCSE | Biology | Form 2 | Topic 1 Transport in Plants

Lesson objectives

By the end of this topic, you should be able to:

• Define transpiration and state its importance.
• Explain how water rises up the stem.
• State the factors affecting the rate of transpiration.
• Describe the opening and closing of stomata and adaptations to dry habitats.

Summary

Transpiration is the loss of water vapour from a plant, mainly through the stomata. The evaporation creates a pull that draws a continuous column of water up the xylem — the transpiration pull, held together by cohesion between water molecules. Rate rises with anything that speeds evaporation, and plants of dry habitats show clear adaptations to reduce it.