Tag: long distance transport of water

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Questions Related to long distance transport of water

Multiple choice 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

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.

  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
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Statement B is false (Na+ role is not universally accepted), C is false (water potential of root cells is lower than soil), and D is false (Cohesion-tension theory is the most accepted, not capillary theory).

Multiple choice 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

Force for passive water absorption develops in

  1. Xylem

  2. Aerial parts

  3. Root

  4. Root hairs
Reveal answer Fill a bubble to check yourself
B Correct answer
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). 

Multiple choice 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

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

  1. Transpiration

  2. Root pressure

  3. Turgor pressure

  4. Imbibition pressure
Reveal answer Fill a bubble to check yourself
B Correct answer
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

Multiple choice 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

Force for active water absorption is present in

  1. Xylem

  2. Aerial parts

  3. Root

  4. Root hairs
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Active water absorption is the absorption of water due to forces present in the root. Living cells in active metabolic condition are essential for this. Auxins are known to enhance water absorption (even from hypertonic solution) while respiratory inhibitors reduce the same.

Thus, the correct answer is option (C). 

Multiple choice 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

Cohesive force of water molecules is of the magnitude of 

  1. 1 - 10 atm

  2. 10 - 15 atm

  3. 45 - 200 atm

  4. 15 - 45 atm
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Cohesive force is called as the tensile strength of water. It is the force which acts between the water molecules. The cohesive strength of 47-207 atm. in xylem sap is sufficient to meet the stress of transpiration pull so that water column does not break.
Thus, the correct answer is option (C). 
Multiple choice 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

Rate of water absorption is slow near freezing point because 

  1. Water absorption is a metabolic process

  2. Cell growth stops

  3. Transpiration is reduced

  4. Cell membrane become more viscous
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Rate of water absorption is slow near a freezing temperature because decreased temperature results in the decreased root growth. Also, freezing temperature makes the cell membrane more viscous. There is resistance in water absorption as permeability of cell membrane decrease and viscosity increases.  

Thus, the correct answer is option D.

Multiple choice 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

Prolonged water-logging kills plants due to

  1. Stoppage of root respiration

  2. Dilution of soil nutrients

  3. Dilution of plant cell sap

  4. Leaching of nutrients
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Waterlogging is the saturation of soil with water which excludes air from the groundwater. If waterlogging will be prolonged then air cannot reach up to groundwater and root and it will result in the stoppage of root respiration.
So, the correct answer is 'Stoppage of root respiration'.
Multiple choice 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

Which of the following is not an important factor in the regulation of transpiration?

  1. Light

  2. Temperature

  3. Humidity

  4. Nitrogen content in the soil
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Transpiration is the evaporation of the water molecule from the upper surface of leaves.

(A) The intensity of light is directly proportional to the amount of transpiration.
(B) With the temperature increase, the transpiration also increases.
(C) Humidity also affects the rate of transpiration.
(D) The nitrogen content in the soil does not affect the regulation of transpiration.
So, the correct answer is 'Nitrogen content in the soil'.

Multiple choice 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

The principle by which blotting paper absorbs water is 

  1. Capillary action

  2. Transpiration pull

  3. Root pressure

  4. Absorptive capacity
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
(A)Capillary action is the name of force by which water or any sap is pulled upwards direct through fine fibres or tubes. Blotting paper absorbs the water through capillary action only as thin threads like structure are present in blotting paper.
(B)Transpiration pull is also the process of upward movement of sap but it occurs during the process of transpiration.
(C)Root pressure is the transverse osmotic force causing sap rise in plants.
(D)Absorptive capacity is the capacity of absorption.
So, the correct answer is 'Capillary action'.
Multiple choice 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

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

  1. Sachs

  2. Christian Wolf

  3. Strasburger

  4. Dixon and Joly
Reveal answer Fill a bubble to check yourself
B Correct answer
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'.