Tag: water absorption and ascent of sap in plants

Questions Related to water absorption and ascent of sap in plants

For ascent of sap, capillary force theory was first proposed by

botany water absorption and ascent of sap in plants factors affecting the transport of water and minerals in plants ascent of sap long distance transport of water

  1. Sachs

  2. Christian Wolf

  3. Strasburger

  4. Dixon and Joly

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Correct Option: B
Explanation:

Scientist Christian Wolf proposed the theory of capillary force for the ascent of sap. He proposed that when water is present in fine tubes then a force develops which causes ascent of sap which is known as capillary force.

So, the correct answer is 'Christian wolf'.

Capillarity theory is the most accepted theory of water movement through the plants.

botany water absorption and ascent of sap in plants factors affecting the transport of water and minerals in plants ascent of sap long distance transport of water

  1. True

  2. False

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Correct Option: B
Explanation:

The cohesive-adhesive theory is the most accepted theory of water movement through the plants.

So, the correct answer is 'False'.

Passive absorption occurs due to 

botany water absorption and ascent of sap in plants factors affecting the transport of water and minerals in plants ascent of sap long distance transport of water

  1. Tension in root

  2. Tension in xylem sap

  3. ATP

  4. None of the above

Show answer
Correct Option: B
Explanation:

Passive absorption is the absorption without the use of energy or ATP.

It occurs when there is tension in xylem sap which causes concentration gradient and liquid moves without the use of energy according to the concentration gradient.
So, the correct answer is 'Tension in xylem sap'

Capillary pores are

botany water absorption and ascent of sap in plants factors affecting the transport of water and minerals in plants ascent of sap long distance transport of water

  1. Percolation pores

  2. Macropores

  3. Micropores

  4. Ultra micropores

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Correct Option: C
Explanation:

Water enters the soil through the pores by the means of capillary action and gravity. Capillary pores are micropores. Micropores hold maximum water by capillary forces. These pores have high water holding capacity as water within these pores is immobile. However, water is available for plant.

Thus, the correct answer is option C.

Water potential of root cells is higher than water potential of soil.

botany water absorption and ascent of sap in plants factors affecting the transport of water and minerals in plants ascent of sap long distance transport of water

  1. True

  2. False

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Correct Option: B
Explanation:

Water potential is the potential energy of water per unit volume taking the reference of pure water. Water potential of the soil is higher than the water potential of root cell.

So, the correct answer is 'False'.

Energy source responsible for upward flow of water is

botany water absorption and ascent of sap in plants factors affecting the transport of water and minerals in plants ascent of sap long distance transport of water

  1. ATP

  2. Sucrose

  3. Solar heat

  4. Sunlight 

Show answer
Correct Option: C
Explanation:

Energy source responsible for upward flow of water is solar heat. Due to increase in the solar heat the temperature increases. The rate of transpiration is high on a bright sunny day due to excessive heat produced by solar heat. The water is lost from guard cell which leads to decrease in the water potential of guard cell as compared to the surrounding cell. To stabilize the water potential in the guard cell water rushes from the neighboring cell which creates a cohesion pull in the xylem vessels to pull the water up to the guard cell. Thus, the rate of water absorption increases when the transpiration is high. 

So, the correct answer is option C.

Which of these is a factor not related to transpiration pull?

botany water absorption and ascent of sap in plants factors affecting the transport of water and minerals in plants ascent of sap long distance transport of water

  1. Capillarity

  2. Adhesion

  3. Cohesion

  4. Ascent of sap

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Correct Option: A
Explanation:
(A) Capillarity is the motion of the liquid in a narrow passage which travels only up to a certain point where it balances the force of gravity of the column.
(B) Adhesion is the force of attraction which leads to the attraction between water and xylem molecule necessary for transpiration pull.
(C) Cohesion is the phenomenon of attraction between similar molecules, which makes water molecule remain attracted to each other while being lifted up by transpiration pull. 
(D) The suction force which makes water to move in an upward direction is the ascent of sap caused by transpiration pull.
So, the answer is, "Capillarity".

Ability to rise in thin tubes and ability to resist pulling force are ................ and  .................. respectively 

botany water absorption and ascent of sap in plants factors affecting the transport of water and minerals in plants ascent of sap long distance transport of water

  1. Tensile strength and capillarity.

  2. Cohesion and adhesion

  3. Capillarity and tensile strength

  4. Adhesion and capillarity

Show answer
Correct Option: C
Explanation:

Capillarity is the ability of water to rise through thin tubes.

The tensile strength of a substance is how well it can resist external force and maintain it's properties.
Cohesion is the attraction of two same particles.
Adhesion is the attraction of two different particles. 
So the correct answer is 'Capillarity and tensile strength'.

Transpiration - cohesion tension theory operates through

botany water absorption and ascent of sap in plants factors affecting the transport of water and minerals in plants ascent of sap long distance transport of water

  1. Active absorption

  2. Passive absorption

  3. Active and Passive absorption

  4. Apoplastic movements

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Correct Option: B
Explanation:
(A) Active absorption is the absorption process when it is being driven by the force present in the root which occurs through osmosis or use of active transport to move molecules of solutes to change the water concentration gradient.
(B) The force for passive absorption originates in the aerial part of the plant due to loss of water in transpiration which causes upward motion and cohesion theory is a theory of intermolecular attraction that explains the process of upward flow of water through the xylem.
(D) Apoplastic movement is the movement of water through the apoplast between loosely packed cortical cell which occurs in the root.
So, the answer is, "Passive absorption".

Active absorption of water by roots from the soil is mainly affected by 

botany water absorption and ascent of sap in plants factors affecting the transport of water and minerals in plants ascent of sap long distance transport of water

  1. Tension in cell sap due to transpiration.

  2. Hydrophobic nature of root hair.

  3. Typical tissue organisation.

  4. Osmotic concentration of xylem sap.

Show answer
Correct Option: D
Explanation:

Active absorption is the movement of water molecule along the gradient with the use of energy.

Osmotic pressure is the movement of a solute particle from low concentration to high concentration through a semi-permeable membrane.
So, the water will move from a higher concentration to a lower concentration.

So, the correct option is 'Osmotic concentration of xylem sap'.