Plant Transport Mechanisms and Functions

The video tutorial covers plant transport mechanisms, focusing on xylem and phloem. It explains how xylem sap moves water and minerals from roots to leaves through adhesion and cohesion. The concept of water potential is discussed, highlighting its role in transpiration and evaporation. The tutorial also covers bulk flow and root pressure, and how plants control transpiration via stomates. The mechanism of stomate opening and closing is detailed, involving potassium ion transport. Finally, the video explains sugar transport in phloem from source to sink, emphasizing active transport and the role of water potential.

What is the primary function of xylem in plants?

• Transporting sugars from leaves to roots

• Providing structural support to the plant

• Transporting water and minerals from roots to leaves

• Storing nutrients for later use

How does water move within the plant according to water potential?

• From high to low water potential

• From low to high water potential

• Only when the plant is in direct sunlight

• Randomly without any potential difference

What role do guard cells play in plant transpiration?

• They provide structural support to the leaves

• They transport sugars to the roots

• They open and close stomates to regulate water loss

• They store water for the plant

Which environmental condition causes stomates to close?

• High carbon dioxide levels

• Dry weather

• High humidity

• Low light levels

What triggers the opening of stomates in response to light?

• Red light

• Infrared light

• Blue light

• Green light

What is the main mechanism for loading sugars into the phloem?

• Passive diffusion

• Gravity-driven flow

• Simple osmosis

• Active transport using ATP

What is the term used to describe the movement of sugars from leaves to roots?

• Transpiration pull

• Cohesion-tension theory

• Source to sink flow

• Root pressure push

During which season does the direction of sugar transport reverse in plants?

• Spring

• Fall

• Summer

• Winter

What experimental evidence supports the concept of positive pressure in phloem transport?

• Monitoring leaf growth rates

• Measuring sugar flow in cut aphid heads

• Observing water movement in xylem

• Tracking mineral uptake in roots

What happens to sugars in the roots during winter?

• They are transported back to the leaves

• They are converted into starch for storage

• They are lost through transpiration

• They are immediately used for energy