Related Questions
Given below are two statements:
Statement I: The transpiration pull generated by water loss can create enough tension to lift a xylem-sized column of water over 130 meters high.
Statement II: Transpiration plays a significant role in cooling leaf surfaces, sometimes by 10 to 15 degrees, due to evaporative cooling.
In the light of the above statements, choose the most appropriate answer from the options given below:
Both Statement I and Statement II are correct
Both Statement I and Statement II are incorrect
Statement I is correct but Statement II is incorrect
Statement I is incorrect but Statement II is correct
The pressure-flow hypothesis explains the translocation of sugars in the phloem. Which of the following statements regarding this hypothesis is INCORRECT?
Active loading of sugars at the source creates a high solute concentration in the sieve tubes.
Water moves from the xylem to the phloem at the source, increasing turgor pressure.
Sugars are unloaded at the sink, lowering the solute concentration and water potential.
Water moves from the sink to the source via the phloem, driven by a pressure gradient.
Which of the following correctly describes the apoplastic pathway in plants?
Movement through the cytoplasm
Movement through plasmodesmata
Movement through cell walls and intercellular spaces
Movement across cell membranes
Water moving through the apoplast encounters a barrier that forces it into the symplast. This barrier is located in which tissue layer of the root?
Epidermis
Cortex
Endodermis
Pericycle
Which tissue is responsible for the transport of sucrose from leaves to other parts of the plant?
Xylem
Phloem
Cambium
Pith
Which substance makes the Casparian strip impermeable to water, thus blocking the apoplastic pathway?
Lignin
Cellulose
Suberin
Pectin
Girdling experiments, where the bark of a tree is removed in a ring around the trunk, demonstrate the importance of phloem for translocation. Which observation is NOT expected after girdling?
Accumulation of sugars above the girdle.
Swelling of the bark above the girdle.
Eventual death of the roots due to lack of nutrients.
Increased sugar concentration above the girdle and decreased sugar concentration below the girdle, with no effect on xylem function.
Which of the following is NOT a major driving force for long-distance transport in plants?
Transpiration pull
Root pressure
Active transport
Diffusion
The cohesion-tension theory explains the ascent of sap in the xylem primarily due to:
Root pressure
Capillary action
Active transport of water
The cohesive properties of water and transpiration pull
Which of the following is NOT a long-distance transport pathway in plants?
Xylem
Phloem
Apoplast
Symplast
