Tag: transport in the phloem of plants

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Questions Related to transport in the phloem of plants

Multiple choice biology transport in plant transport in the phloem of plants vascular tissue permanent tissue

Which of the following is done during ringing experiment

  1. Bark is removed

  2. Pith is removed

  3. Xylem is removed

  4. All of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In ringing experiment, the bark ring is scraped away which also removes the phloem causing xylem exposure. In this experiment, sugar moves downwards in the stem but the movement is stopped by the ring. As as result sugar bulge forms above the ring. This suggest that sugar transports down in the stem in the phloem.

So the answer is D.

Multiple choice biology transport in plant transport in the phloem of plants vascular tissue permanent tissue

Which one dies first when a ring of bark is removed?

  1. Shoot

  2. Root

  3. None

  4. Both shoot and root die simultaneously
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
The total removal of bark is called girdling, so when the bark is removed the roots will die first as they will starve without the sugar production by the leaves transported down.
So, the correct answer is 'Root'.
Multiple choice biology transport in plant transport in the phloem of plants vascular tissue permanent tissue

The loss of which will harm the tree most

  1. Bark

  2. Half the leaves

  3. Half the branches

  4. All the leaves
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
(A) The loss of bark called girdling will eventually lead to the death of the plant.
(B) Loss of half of the leaves will affect the rate of transpiration and the production of starch.
(C) Loss of half of the branches would not affect plant much.
(D) Loss of all of the leaves will either make the new leaf growth or if the plant is weak it will die.
So, the correct answer is 'Bark'.
Multiple choice biology transport in plant transport in the phloem of plants vascular tissue permanent tissue

Loading of phloem means

  1. Elongation of phloem cells

  2. Separation of phloem parenchyma

  3. Strengthening of phloem fibres

  4. Pouring of sugar into phloem
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Loading of phloem is a process of loading carbon into the phloem for transport to different sinks in a plant. Sinks include metabolism, growth, storage and other processes or organ that need carbon solutes to persist.

So, the correct answer is 'Pouring of sugar into phloem'.

Multiple choice biology transport in plant transport in the phloem of plants vascular tissue permanent tissue

Radioactive tracer studies with $^{14}$C have shown that

  1. Phloem transports organic nutrients

  2. Phloem transports inorganic nutrients

  3. Xylem transports inorganic nutrients

  4. Xylem transports organic nutrients
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The radioactive tracer is a chemical compound used to determine the atoms and molecules by the virtue of radioactive decay. The age of a tree, transportation of solute through phloem etc is seen through the use of radioactive of carbon. 

So, the correct answer is 'Phloem transports organic nutrients'.

Multiple choice biology transport in plant transport in the phloem of plants vascular tissue permanent tissue

End walls of tracheids and Vessels respectively are

  1. Pitted and perforated

  2. Perforated and pitted

  3. Both perforated

  4. Both pitted
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Tracheids and vessels both have pits but vessels have an opening which connects single individual vessel elements to form a single tube. These end openings are called perforation plates. Tracheids are imperforate, have pit pairs on common walls.

So, the correct answer is 'Pitted and perforated'

Multiple choice biology transport in plant transport in the phloem of plants vascular tissue permanent tissue

A column of water within xylem vessels of tall trees does not break under its weight because of 

  1. Dissolved sugar in water

  2. Tensile strength of water

  3. Lignification of xylem vessels

  4. Positive root pressure
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Positive root pressure pushes up the water. 

Lignification of xylem vessels provide mechanical support.
Dissolved sugar in water reduces it's water potential but has no role in maintaining a column.
Tensile strength of water is its ability to resist the break in column due to forces like the transpiration pull. This is achieved by properties of water like Cohesion and Adhesion.
So the correct answer is 'Tensile strength of water'.

Multiple choice biology transport in plant transport in the phloem of plants vascular tissue permanent tissue

Which of the following statement is true?

  1. Vessels are multicellular with wide lumen.

  2. Tracheids are multicellular with narrow lumen.

  3. Vessels are unicellular with narrow lumen.

  4. Trachieds are unicellular with wide lumen.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Vessels are multicellular with wide lumen. They are made up of vessel  elements lying one above the other. The wall of vessels is hard but not thick having wide lumen. Whereas tracheids are unicellular with narrow lumen. 

Thus, the correct answer is 'Vessels are multicellular with wide lumen'.