Chapter 22, Problem 22A

Summary Introduction

To determine:

Environmental factors that affect the rate of transpiration in plants.

Introduction:

Transpiration is a process that controls the movement of water between the plant and the environment. This process is carried out by the evaporation process from the aerial part of the plants. This process is directly involved in the water cycle process of the environment. The amount of water vapor lost to the environment is controlled by the guard cell of stomata.

Explanation of Solution

Many environmental factors affect the transpiration process; first of all temperature.

In higher temperatures the movement of water molecules increases and the evaporation rate also gets high. In low temperatures, the evaporation rate decreases so do the transpiration process decreases.

The other factor that might affect the transpiration process is light intensity. In the high intensity of light, the photosynthesis process gets increased as a result of which the glucose amount to be stored in the guard cell also get increased. This decreases the water potential of the leaves; therefore, the transpiration rate becomes constant.

Next factor is humidity. In high humidity the water potential gradient in stomata and the environment is empty, and therefore, the transpiration rate is low.