Tag: ascent of sap

Questions Related to ascent of sap

Movement of sap through the plant is facilitated 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. Absorption by roots and gravitational force

  2. Gravitational force and pull due to transpiration

  3. Pull due to transpiration and absorption by roots

  4. Weight of sap and gravitational force

Show answer
Correct Option: C

Capillary action can cause

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. Water uptake in tall plants

  2. Water uptake in small plants

  3. Both of the above

  4. None of the above

Show answer
Correct Option: B
Explanation:

Water tends to rise up inside the narrow tubes by capillary action. This is because of the cohesive force of the water molecules. Because of this water rises up in the xylem vessel to some distance up dragging other water molecules present below them this capillary rise cannot take up water to tall plants though this may be possible in very small plants. Thus, the correct answer is option B.

Water rise in capillary tubes because of
i Attraction of water molecules to each other
ii Presence of a weak electrostatic force
iii Cohesive force

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. I, II

  2. II, III

  3. I, III

  4. All of the above

Show answer
Correct Option: D
Explanation:

Cohesive force is the one in which water and the walls of the tube are attracted to each other.

Attraction of water molecules towards each other and presence of weak electoratic force is collectively known as adhesive force as the electrostatic charges help attract two water molecules towards each other.
All these forces help water to rise in a capillary.
So the correct answer is 'All of the above'.

Read the passage and answer the following question.
Wet mounts of three living samples of Elodea cells are prepared for viewing under the light microscope. Each slide is mounted with a different solution and viewed after 5 minutes.
Sample A - Elodea + 5 drops of 10% $\displaystyle NaCl$
Sample B - Elodea + 5 drops of isotonic saline
Sample C - Elodea + 5 drops of distilled water
The correct statement about this experiment 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. The movement of salt is the dependent variable.

  2. The elodea cells in sample C are in a hypotonic solution.

  3. There is no passage of water in either direction in sample B.

  4. $\displaystyle NaCl$ is a toxin that would destroy any cell, no matter the concentration.

  5. You cannot predict with any certainty what would happen to these cells; they are living organisms.

Show answer
Correct Option: B
Explanation:

Distilled water is a hypotonic environment for the Elodea which causes endosmosis. Water will flow into the cells because there is more water/less solute in the surrounding solution.

Therefore, the correct answer is option B.

The movement of sap within the xylem is increased by

I. Water movement into guard cell's vacuoles.
II. Humidity increases in the surrounding air.
III. Root endodermis prevents ions from entering the xylem.

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. I only

  2. II only

  3. I and III

  4. II and III

  5. I, II, and III

Show answer
Correct Option: A
Explanation:

The upward movement of water from the root to aerial parts of the plant body is called ascent of sap or translocation of water. This movement takes place through the xylem due to positive root pressure and is increased by the movement of water into the guard cells vacuoles. Thus, the correct answer is option A.

Read the passage and answer the following question.
Wet mounts of three living samples of Elodea cells are prepared for viewing under the light microscope. Each slide is mounted with a different solution and viewed after 5 minutes.
Sample A - Elodea + 5 drops of 10% $\displaystyle NaCl$
Sample B - Elodea + 5 drops of isotonic saline
Sample C - Elodea + 5 drops of distilled water
The results of this experiment describes

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. Hydrolysis.

  2. Dehydration.

  3. Active transpot.

  4. Polymerization.

  5. Osmosis.

Show answer
Correct Option: E
Explanation:

Osmosis is specifically the diffusion of water. Water always flows passively down a gradient, from a high concentration of water to a low concentration of water. Therefore, the result of this experiment shows osmosis as water would move from high concentration to low concentration. 

Thus, the correct answer is option E.

A sufficient atmospheric pressure required to push the water upto the top of tall plants must be

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. 2 atm

  2. 6 atm

  3. 20 atm

  4. All of the above

Show answer
Correct Option: C
Explanation:

Taller plants like Eucalyptus need higher pressure to raise the water up. While the value of root pressure ranges from 2.5 atmospheres. A pressure of about 20 atm. is required to raise the water to tops of tall trees.

Which of the following statement is/are  not true :-
A.In CAM plants stomata open during dark and remain closed during the day
B.Role of $Na^{+}$ in stomatal opening is now universally accepted
C.The water potential of root cells is higher than the water potential of soil
D.Capillary theory is the most accepted theory of water movement through plants
E.The walls of xylem vessels made up of ligno-cellulose have strong affinity for water molecules.

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. B ,C and E only

  2. B ,C and D only

  3. A ,B and C only

  4. B and C only

  5. A and E only

Show answer
Correct Option: B

Force for passive water absorption develops in

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. Xylem

  2. Aerial parts

  3. Root

  4. Root hairs

Show answer
Correct Option: B
Explanation:

The force for passive water absorption originates in the aerial parts of the plant due to loss of water in transpiration. This creates a tension or low water potential of several atmospheres in the xylem channels. 

Thus, the correct answer is option (B). 

The phenomenon which forces water upwards into tracheary elements of xylem in the root region 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. Transpiration

  2. Root pressure

  3. Turgor pressure

  4. Imbibition pressure

Show answer
Correct Option: B
Explanation:

Root pressure is the force in root region that helps to drive water or sap upwards into tracheary elements of xylem. Water is absorbed through the root hairs from the soil. During low transpiration there is no transpiration pull that time root pressure increases and water moves upwards in xylem elements