18) Transpiration and Stomata

How does light intensity affect transpiration rate?

Brighter light increases transpiration by keeping stomata open; they close in the dark.

What is the relationship between temperature and transpiration?

Warmer temperatures increase transpiration rates because water particles have more energy to evaporate.

How does air flow influence transpiration?

Strong air flow enhances transpiration by removing water vapor around leaves, promoting diffusion.

What effect does humidity have on transpiration?

Lower humidity increases transpiration rates; high humidity reduces the concentration gradient for diffusion.

What is a potometer used for?

A potometer measures water uptake by a plant, estimating the rate of transpiration.

How do guard cells regulate stomata?

Guard cells open and close stomata based on water availability: turgid when full, flaccid when water is scarce.

What is the role of stomata in plants?

Stomata facilitate gas exchange for photosynthesis and regulate water loss through transpiration.

Why do guard cells close at night?

They close at night to conserve water since photosynthesis does not occur in the dark.

What structural features help guard cells function?

Guard cells have thin outer walls and thickened inner walls to enable the opening and closing of stomata.

Why is maintaining a low concentration of water vapor outside the leaf important?

It promotes efficient diffusion of water vapour from the inside of the leaf to the outside, enhancing transpiration.