factors effecting transpiration

How do you measure factors that affect transpiration

The rate of transpiration can be measured in the lab using a potometer

what’s on limitations of the promoter

A potometer actually measures the rate of water uptake by the cut stem, not the rate of transpiration; and these two are not always the same.

what are some environmental factors that effect transpiration

1. temperature

2. humidity

3. air movement

4. light

explain temp

1. Temperature. High temperature increases the rate of evaporation of water from the surface of spongy cells because it increases the kinetic energy of the water molecules. This raises the water potential in the sub-stomatal air space and means the molecules are moving faster, so transpiration increases.

explain humidity

1. Humidity. High humidity means a higher water potential in the air surrounding the stomata, so a lower water potential gradient between the sub-stomatal air space and the air outside, so less evaporation.

explain air movement (wind)

1. Air movements. Wind blows away saturated air from around stomata, replacing it with drier air with a lower water potential, so increasing the water potential gradient and increasing transpiration.

explain light

1. Light. Light stimulates plants to open their stomata to allow gas exchange for photosynthesis. As a side effect this also increases the rate of transpiration. This is a problem for some plants as they may lose water during the day and wilt.