Tag: absorption by roots - the processes involved

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Multiple choice biology absorption by roots - the processes involved root pressure transportation in plants factors affecting the transport of water and minerals in plants

If the stem of the plant is cut just above the root then

  1. Water will seep or exude out of the cut end for a considerable amount of time.

  2. Water will seep or exude out of the cut end continuously

  3. Both A and B

  4. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Root pressure can be defined as the pressure exerted by the cortical cells of the root upon the sap in the xylem vessels which pushes the sap upwards if the stem of the plant is cut just above the root, water seeps or exudes out of the cut end of the stem for a considerable period of time. This indicates that there is a force pushing water up the stem from the roots.

Multiple choice biology absorption by roots - the processes involved root pressure transportation in plants factors affecting the transport of water and minerals in plants

Root pressure is a _______

  1. Pulling force

  2. Pushing force

  3. Both A and B

  4. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Root pressure provides a force which causes pushing of water in a stem. A continuous flow of water is maintained in the plants because the leaves transpire water through stomata and to replace the lost water, the water drawn by the roots moves up.

Multiple choice biology absorption by roots - the processes involved root pressure transportation in plants factors affecting the transport of water and minerals in plants

Root pressure can be measured by

  1. Attaching a barometer to the cut end of the stem

  2. Attaching a manometer to the cut end of the stem

  3. Attaching a thermometer to the cut end of the stem

  4. Attaching a potometer to the cut end of the stem.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The root pressure can be measured by attaching a suitable mercury manometer to the cut end of the stem. Root pressure provides a force which causes pushing of water in the stem. A continuous flow of water is maintained in the plants because the leaves transpire water through stomata and to replace the lost water the water drawn by the roots moves up.

Multiple choice biology absorption by roots - the processes involved root pressure transportation in plants factors affecting the transport of water and minerals in plants

Root pressure is maximum when

  1. Transpiration is high and absorption low

  2. Transpiration is very low and absorption is high

  3. Transpiration is very high and absorption is high

  4. Transpiration and absorption both are slow
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Root pressure is the positive pressure that develops in the roots of the plants by active absorption of nutrients from the soil. The active absorption depends on the active accumulation of solute in xylem sap. Root pressure in maximum when transpiration is very low and absorption is high because transpiration is the output of water from a plant, and absorption is the input of water into a plant. If the output is low and input is high, the pressure will be at its greatest. 

So, the correct answer is 'Transpiration is very low and absorption is high'.

Multiple choice biology absorption by roots - the processes involved root pressure transportation in plants factors affecting the transport of water and minerals in plants

Who defined the term root pressure? 

  1. Stephan Hales

  2. Mendel

  3. Griffith

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

Root pressure is defined as the osmotic pressure in the root cell through which the water is translocated into leaves from the stem. The term root pressure was given by Stephan Hales. Thus the correct answer is option A.

Multiple choice biology absorption by roots - the processes involved root pressure transportation in plants factors affecting the transport of water and minerals in plants

Root pressure is maximum when

  1. Transpiration is high and absorption is very low

  2. Transpiration is very low and absorption is high

  3. Transpiration is very high and absorption is also high

  4. Transpiration and absorption both are slow
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Stephentiales (1727) coined the term root pressure. Root pressure is developed when rate of water absorption is more than the rate of transpiration.

Multiple choice biology absorption by roots - the processes involved root pressure transportation in plants factors affecting the transport of water and minerals in plants

Which of the following statement is wrong in root-presure concept of ascent of sap ?

  1. Water can be raised to a height of 6'-7'.

  2. Water moves upward in the absence of shoot.

  3. Water moves by this force is slow.

  4. Root pressure operates in all the plants.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Root pressure is not operated in lower plants and plants of small height and aquatic plants because they have several other mechanisms to conduct water. Root pressure occurs in the xylem of some vascular plants when the soil moisture level is high either at night or when transpiration is low during the day.
So the correct answer is 'Root pressure operates in all the plants'.
Multiple choice biology absorption by roots - the processes involved root pressure transportation in plants factors affecting the transport of water and minerals in plants

Root pressure may be caused by 

  1. Osmotic flow of water into xylem of absorbing part of root.

  2. Loss of water from xylem of the plant due to transpiration.

  3. Low water potential of leaves.

  4. High water potential of leaves.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

When there is no transpiration then due to lack of transpiration pull water does not move upwards. At this time through osmosis water is absorbed from the soil and it accumulates in xylem region of the root .The accumulation through osmosis causes root pressure and water moves upwards.
Thus, the correct option is (A).

Multiple choice biology absorption by roots - the processes involved root pressure transportation in plants factors affecting the transport of water and minerals in plants

Root pressure is due to  

  1. Active absorption/ transportation

  2. Passive absorption/ transport

  3. Increased transpiration

  4. Increased photosynthesis
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
(A)Active absorption is the absorption of water by roots with the help of ATP.
Root pressure is due to active absorption and active distribution of mineral nutrients. It is measured by potometer.
(B)Passive adsorption is the energy independent process.
(C)Transpiration is the evaporation of water from the upper surface of the leaves.
(D)Photosynthesis is the process of making of glucose.
So, the correct answer is (A) 'Active absorption/ transportation'.
Multiple choice biology absorption by roots - the processes involved root pressure transportation in plants factors affecting the transport of water and minerals in plants

Exudation of xylem sap on cutting of a shoot is due to

  1. Gutttation

  2. Root pressure

  3. Transpiration

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
(A) Guttation is the secretion of droplets from the pores of the tree.
(B) When stem base is cut xylem sap releases and it is due to root pressure [It push the xylem sap upward so when we cut stem base the pulling force of root pressure works].
(C) Transpiration is the evaporation of water from the upper surface of the leaves.
So, the correct answer is 'Root pressure'.