Tag: transport of water in plants

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Multiple choice botany water absorption and ascent of sap in plants apoplast and symplastic pathway transport of water in plants water transport

Following are the differences between apoplast pathway and symplast pathway. Which of the given differences is/are correct?

Apoplast pathway Symplast pathway
(i) It consists of non-living parts of plant body, i.e., cell walls and intercellular spaces. It consists of living parts of plant body, i.e., protoplasts connected by plasmodesmata.
(ii) There is little resistance in the movement of water Some resistance occurs in the movement of water through symplast
(iii) It is slightly slower It is faster
(iv) Metabolic state of root directly affects apoplast pathway Metabolic state of root does not affect symplast pathway

  1. (iii) only

  2. (i) and (iii) only

  3. (iii) and (iv) only

  4. (ii) and (iii) only
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Apoplast pathway is faster while symplast pathway is slightly slower. Metabolic state of root does not affect apoplast pathway while metabolic state of root directly affects symplast pathway.

Multiple choice botany water absorption and ascent of sap in plants apoplast and symplastic pathway transport of water in plants water transport

In which of the following pathways, movement of water occurs from one cell to another cell through plasmodesmata?

  1. Apoplast pathway

  2. Symplast pathway

  3. Vacuolar pathway

  4. Transmembrane pathway
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In symplast pathway, water passes from cell to cell through their protoplasm. It does not enter cell vacuoles. The cytoplasm of the adjacent cells are connected through plasmodesmata. Symplastic movement is aided by cytoplasmic streaming of individual cells.

Multiple choice botany water absorption and ascent of sap in plants apoplast and symplastic pathway transport of water in plants water transport

Terms apoplast and symplast were first used by

  1. Clark

  2. Munch

  3. Dixon

  4. Lundegardh
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Apoplast refers to the non living component of plant like intercellular spaces and cell wall. Transportation through apoplast is fast. 

Symplast refers to living component of plant ie cell membrane and protoplasm. Transportation through symplast is slow process. 
E. Munch (1932), a German physiologist introduced the concept of apoplast and symplast, which is valuable in understanding the pathway of water movement through the root.

Multiple choice botany water absorption and ascent of sap in plants apoplast and symplastic pathway transport of water in plants water transport

Choose the correct answers from the alternatives given.
If cell A with OP = 5 and TP = 4 is surrounded by cells with OP = 3 and TP = 1, what will be the direction of water movement?

  1. From other cells to cell A

  2. From cell A to other cells

  3. Water will not move

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

DPD or diffusion pressure deficit determines the flow of water. Water moves from low DPD to high DPD. 

DPD is given by: DPD = OP - TP.
In cell A, DPD = 5 - 4 = 1.
In other cells, DPD = 3 - 1 = 2.
Since water moves from low DPD to high DPD, here the movement occurs from cell A to the other cells.
Hence, the correct answer is 'From cell A to other cells'.

Multiple choice botany water absorption and ascent of sap in plants apoplast and symplastic pathway transport of water in plants water transport

The transportation of water and minerals from the root to the leaves is known as ________

  1. Capillary action

  2. Accent of sap

  3. Climbing

  4. Transportation
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The transportation of water and dissolved minerals from the root to the leaves is known as ascent of sap. It is transported through xylem tissues. During transportation, there is large accumulation of mineral ions in the root hair cells by active transport. This results in the higher water concentration in the soil as compared to the cell sap of the root hair. Hence, water diffuses from the soil into the root hair. The root hair cells become turgid. From root hair cells, the water moves into the cortical cells. From the cortical cells, the water reaches the endodermis by osmosis. The endodermis then pushes water into the xylem tubes through passage cells.

Thus, the correct answer is 'Ascent of sap.'

Multiple choice botany water absorption and ascent of sap in plants apoplast and symplastic pathway transport of water in plants water transport

Which is shown by the experiment Ascent of sap?

  1. The food materials are transmitted by phloem

  2. Water is transmitted by phloem

  3. Water is transmitted by xylem

  4. The food material is transmitted by xylem
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The ascent of sap experiment demonstrates the absorption of water by root cells if plants and their upwards movement. The sap is the water and minerals absorbed by the roots and they are pushed upwards into the xylem and then it goes to other regions of the plant.

The upward movement of water and minerals is known as ascent of sap.
So the correct answer is 'Water is transmitted by the xylem'.

Multiple choice botany water absorption and ascent of sap in plants apoplast and symplastic pathway transport of water in plants water transport

Ascent of sap will be maximum during

  1. Daytime

  2. Night time

  3. Early morning

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

Cohesion transpiration pull theory was put forward by Dixon and Jolly in 1894. It is also known as Dixon's theory of ascent of sap. During day time, there will be maximum water loss due to transpiration, hence, transpiration pull will also be maximum during day time. Consequently, maximum ascent of sap will occur during day time.

Multiple choice botany water absorption and ascent of sap in plants apoplast and symplastic pathway transport of water in plants water transport

The rate of transpiration ........... the process of ascent of sap.

  1. Increases

  2. Decreases

  3. Do not affect

  4. Increases and then decreases
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Transpiration causes the development of a pull or a negative pressure region which created a suction force to aid the ascent of sap. It increases the process of ascent of sap.

So the correct answer is 'Increases'.

Multiple choice botany water absorption and ascent of sap in plants apoplast and symplastic pathway transport of water in plants water transport

The root pressure theory considers ........... responsible for the ascent of sap.

  1. Gravitational pull

  2. Hydrostatic pressure

  3. Capillary force

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

The root pressure theory considers that hydrostatic pressure developed in the roots is responsible for pushing the water through the column. It depends on the active accumulation of minerals in the root cells which then causes passive absorption of water creating a high pressure.

It neglects the effect of gravity.
Capillary force is not the driving force in this theory.
Many small herbaceous plants only depend on root pressure for ascent of Sap.
So the correct answer is ' Hydrostatic pressure'.