Which of the following is NOT a major driving force for long-distance transport in plants?
Transpiration pull
Root pressure
Active transport
Diffusion
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
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 of the following is NOT a long-distance transport pathway in plants?
Xylem
Phloem
Apoplast
Symplast
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.
A researcher is studying long-distance transport in a plant. They introduce a radioactive tracer into the phloem sap of a source leaf. Which of the following would LEAST likely be observed after a period of time?
Movement of the tracer towards a developing fruit
Presence of the tracer in the root tips
Detection of the tracer in a sink leaf
Significant accumulation of the tracer in mature xylem vessels of the source leaf
The Casparian strip in the endodermis primarily restricts the movement of water via the:
Apoplast
Symplast
Transmembrane pathway
Vacuolar pathway
The movement of minerals through the apoplast is interrupted at the:
Epidermis
Cortex
Casparian strip
Phloem
Which of the following manipulations would MOST directly inhibit the loading of sucrose into the sieve tube elements at the source?
Decreasing the hydrostatic pressure in the sieve tube elements
Blocking plasmodesmata between companion cells and sieve tube elements
Increasing the concentration of sucrose in the sink
Inhibition of apoplastic proton pumps in companion cells
Which of the following is NOT a major driving force for long-distance transport in plants?
Transpiration pull
Root pressure
Active transport
Diffusion
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.
