Tree Physiology and Water Movement

The video tutorial explains the process of transpiration in plants, focusing on how water moves through the plant and the role of stomata in gas exchange. It introduces the cohesion tension theory, which describes how water is pulled up from the roots to the leaves. The video also presents evidence supporting this theory, such as the effect of cutting a plant stem and measuring tree trunk diameter changes. The tutorial concludes with a preview of the next topic, measuring water uptake using a potometer.

What is the primary function of the waxy cuticle on a leaf?

• To reduce water loss

• To aid in photosynthesis

• To facilitate gas exchange

• To absorb sunlight

Which gas diffuses into the leaf during photosynthesis?

• Hydrogen

• Nitrogen

• Oxygen

• Carbon dioxide

What is the process called when water vapor diffuses out of the leaf?

• Photosynthesis

• Transpiration

• Respiration

• Condensation

What causes water to move by osmosis in the leaf?

• Increase in water potential

• Decrease in water potential

• Increase in temperature

• Decrease in light intensity

What is the term for the movement of water from roots to leaves?

• Photosynthesis

• Respiration

• Transpiration stream

• Evaporation

What type of attraction is responsible for water molecules sticking to each other?

• Adhesion

• Cohesion

• Capillary action

• Tension

What is the effect of cohesion and adhesion in the xylem vessels?

• Facilitates capillary action

• Decreases transpiration

• Increases water potential

• Prevents water movement

What happens when a plant stem is cut, according to the cohesion tension theory?

• Water flows out

• Air is sucked in

• Water movement increases

• Photosynthesis stops

How does the diameter of a tree trunk change during maximum transpiration?

• It increases

• It remains the same

• It fluctuates

• It decreases

What does the reduction in tree trunk diameter during transpiration suggest?

• Increased water absorption

• Negative pressure or tension in the xylem

• Positive pressure in the xylem

• Decreased photosynthesis