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Multiple choice botany plant water relation diffusion pressure deficit other pressure components osmosis in plants

Which of the following is not correct about $DPD$?

  1. Its the loss of diffusion pressure
  2. Maximum valu of $DPD$ is equal to $OP$
  3. $DPD$ of pure $H _{2}O$ is zero
  4. Increase in $TP$ of a cell decreases $DPD$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The term diffusion pressure deficit (DPD) is the reduction in the diffusion pressure of water in solution or cell over its pure state due to presence of solutes in it and forces opposing diffusion. Diffusion pressure of water is maximum and its theoretical value is 1236 atm. DPD of a solution is equal to its osmotic pressure i.e. DPD = OP(of solution). DPD of a cell is influence by both osmotic pressure and wall pressure (turgor pressure) which opposes the endosmotic entry of water, i.e. DPD = OP - Wall pressure. DPD is directly proportional to the concentration of the solution. DPD decreases with dilution of solution. The actual pressure with which cell absorbs water is called "suction pressure".

So the correct option is 'DPD of pure H$ _2$O is zero'.

Multiple choice botany plant water relation diffusion pressure deficit other pressure components osmosis in plants

Which of the following is incorrectly match :-

  1. For fully turgid cell $ \Rightarrow $ DPD $ = 0 $
  2. DPD of solution is vessel $ \Rightarrow $ $ OP - TP = 0 $
  3. For full turgid cell $ \Rightarrow OP = TP $
  4. DPD for a flaccid cell $ \Rightarrow DPD = OP $
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

It is reduction in the diffusion pressure of water in solution or cell over its pure state due to presence of solutes in it and forces opposing diffusion. Diffusion pressure of water is maximum and its theoretical value is 1236 atm. DPD of a solution is equal to its osmotic pressure i.e. DPD = OP(of solution) and in this case the DPD is not zero. For a turgid cell OP=TP and DPD=0. DPD for a flaccid cell is maximum and is equal to OP.


So the correct option is 'DPD of solution is vessel ⇒ OP−TP=0'.

Multiple choice botany plant water relation diffusion pressure deficit other pressure components osmosis in plants

Which of the following equation is correct for incipient plasmolysed cell ?

  1. $DPD=OP-TP$
  2. $OP=TP$
  3. ${ \Psi } _{ w }={ \Psi } _{ s }+{ \Psi } _{ p }$
  4. ${ \Psi } _{ w }={ \Psi } _{ s }-{ \Psi } _{ p }$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Diffusion pressure deficit - It is described as the ability of water to move is used to measure in terms of diffusion pressure. 


(C) $\Psi _w = \Psi _s + \Psi _p$

The point during which the protoplast is just pulled or moved away from the cell wall is called incipient plasmolysis.

Multiple choice botany plant water relation diffusion pressure deficit other pressure components osmosis in plants

Which cell has maximum diffusion pressure deficit?

  1. Flacid cell

  2. Turgid cell

  3. Prokaryotic cell

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

Diffusion pressure deficit or DPD is the difference between the pressure of a solution and a pure solvent. It is also called as suction pressure. In order to achieve the equilibrium or attain zero value of DPD, the solvent from low solute concentration or low DPD to high solute concentration or high DPD. In other words, the diffusion pressure deficit is equal to the total of osmotic pressure and turgor pressure. DPD is maximum in pure water. In a flaccid cell, there is no movement of water. In a flaccid cell, there is no turgor pressure. Hence, DPD is equal to the osmotic pressure.

Thus, the correct answer is 'Flaccid cell.'

Multiple choice botany plant water relation diffusion pressure deficit other pressure components osmosis in plants

Find out the incorrect about diffusion pressure(DP)
I. DP $\alpha$ Conc. of solution
II. DP $=$ DP
III. For a fully turgid cell, DP$=0$.

  1. I and II only

  2. II & III only

  3. I & III only

  4. I, II and III
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Diffusion Pressure (DP) is inversely proportional to the concentration of the solute (as solute concentration increases, DP decreases). Statement II is a tautology (DP=DP), and statement III is incorrect because in a fully turgid cell, DPD is zero, but DP is at its maximum (equal to the DP of pure water).

Multiple choice botany plant water relation diffusion pressure deficit other pressure components osmosis in plants

When a cell is placed in water, it takes in water due to

  1. Osmotic pressure

  2. Suction pressure

  3. Translocation

  4. Water potential and TP
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

'Diffusion pressure deficit' (DPD) is also known as suction pressure (SP). DPD is responsible for movement of water in a plant. Water moves from a region or cell of low DPD to a cell or region of high DPD. The DPD is calculated as the difference of osmotic pressure (which is responsible for entry of water into a cell) and turgor pressure (which opposes entry of water into a cell). 

Multiple choice botany plant water relation diffusion pressure deficit other pressure components osmosis in plants

Water enters from the soil into the root hairs due to

  1. Turgor pressure of root hair

  2. Osmotic pressure of root hair

  3. Suction pressure

  4. Diffusion pressure
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Suction pressure is same as DPD (Diffusion Pressure Deficit). Water moves in a plant due to suction pressure or DPD from a region of lower DPD to a region of higher DPD.

Multiple choice botany plant water relation diffusion pressure deficit other pressure components osmosis in plants

The term diffusion pressure deficit was coined by 

  1. De Duve

  2. B.S Meyer

  3. Novikoff

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

The term diffusion pressure deficit (DPD) was coined by B.S Meyer in 1938. 

The amount by which diffusion pressure of a solution is lower than its pure solvent is known as Diffusion Pressure Deficit. DPD of pure water is the lowest. Hence option B is correct.