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Multiple choice botany plant tissues - internal morphology and anatomy theories of meristematic cell development theories of shoot apical meristem development shoot and root apex

According to histogen theory, epidermis is formed by

  1. Dermatogen

  2. Protoderm

  3. Periblem

  4. Plerome
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
  • The histogens at the shoot and root tip in plants as these are derived from the apical meristematic tissues according to the histogen theory given by Hanstein.
  • It consists of three distinct layers:-
  1. Dermatogen is the primary meristem that forms the outer most layer of a plant or a plant part and forms the epidermis.
  2. Periblem is a primary meristem which is located between the plerome and the dermatogen and it forms the cortex.
  3. Plerome is the primary meristem that forms the central core of a plant or plant part which gives rise to the stele (includes the vascular tissue, pith and pericycle).
  • The part of plerome from which vascular tissues are formed is called procambium.
  • So the correct answer is 'Dermatogen'
Multiple choice botany plant tissues - internal morphology and anatomy theories of meristematic cell development theories of shoot apical meristem development shoot and root apex

Concept envisaging three zones of cells in root and stem apices is

  1. Histogen theory

  2. Tunica corpus theory

  3. Meristem theory

  4. Dermatogen theory
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
  • The shoot apical meristem (SAM) consists of three distinct meristematic zones called the Histogens.
  • This is called histogen theory of tissues which was proposed by Hanstein in 1870 explains the activity of both the root and shoot apical meristem.
  • These histogens are present at the growing tips of a stem or a root.
  • These tips consist of three histogens and each of these histogens gives rise to tissues which are different from one another
1) Dermatogen is the primary meristem that forms the outer most layer of a plant or a plant part and forms the epidermis.
2) Periblem is a primary meristem which is located between the plerome and the dermatogen and it forms the cortex.
3) Plerome is the primary meristem that forms the central core of a plant or plant part which gives rise to the stele (includes the vascular tissue, pith and pericycle).
  • The part of plerome from which vascular tissues are formed is called procambium.
So, the correct answer is 'Histogen theory'
Multiple choice botany plant tissues - internal morphology and anatomy theories of meristematic cell development theories of shoot apical meristem development shoot and root apex

Histogen theory was proposed by

  1. Nageli

  2. Schmidt

  3. Hanstein

  4. Wolf
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
  • The shoot apical meristems located at the shoot tip in plants are derived from the apical meristematic tissues according to the histogen theory given by Hanstein in 1868.
  • It consists of three distinct layers:-
1) Dermatogen is the primary meristem that forms the outer most layer of a plant or a plant part and forms the epidermis.
2) Periblem is a primary meristem which is located between the plerome and the dermatogen and it forms the cortex.
3) Plerome is the primary meristem that forms the central core of a plant or plant part which gives rise to the stele (includes the vascular tissue, pith and pericycle).
  • The part of plerome from which vascular tissues are formed is called procambium.
So, the correct answer is 'Hanstein'
Multiple choice botany plant tissues - internal morphology and anatomy theories of meristematic cell development theories of shoot apical meristem development shoot and root apex

According to the concept of waiting meristem, the active region of shoot apex is?

  1. Anneau initial

  2. Meristeme medullaire

  3. Promeristeme sporogene

  4. Promeristeme receptaculaire
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

According to the waiting meristem concept, the 'anneau initial' (initial ring) is the peripheral zone of the shoot apex that remains active and contributes to leaf and stem formation.

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

DPD is equal to :

  1. OP $ \times $ TP (WP)
  2. OP $ + $ TP (WP)
  3. OP $ - $ TP (WP)
  4. TP (WP) $ - $ OP
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
  • Diffusion pressure deficit (DPD) is the amount by which two solutions differ in their diffusion pressure.
  • It is defined as the amount by which the diffusion pressure of water or solvent in a solution is lower than that of pure water or solvent is known as diffusion pressure deficit. It allows for easy absorption of water due to the diffusion pressure gradient. Water moves from lower DPD to higher DPD.
  • It is equal to the difference between osmotic pressure and turgor pressure.
  • DPD of a cell is influenced by both osmotic pressure and wall pressure (turgor pressure) which opposes the endosmotic entry of water, i.e. DPD = OP - wall pressure.
So, the correct answer is option C.
Multiple choice botany plant water relation diffusion pressure deficit other pressure components osmosis in plants

Water passes into cell or one cell to another due to 

  1. O.P.

  2. D.P.D.

  3. W.P.

  4. Diffusion
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Diffusion pressure deficit (DPD) is the amount by which two solutions differ in their diffusion pressure. The amount by which the diffusion pressure of water or solvent in a solution is lower than that of pure water or solvent is known as diffusion pressure deficit. It allows easy absorption of water due to diffusion pressure gradient. Water moves from lower DPD to higher DPD.
So, the correct answer is option B.
Multiple choice botany plant water relation diffusion pressure deficit other pressure components osmosis in plants

The actual pressure with which water enters into the cell is called as

  1. D.P.D.

  2. O.P.

  3. W.P.

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

Actual flow of water is decided by the deficit in diffusion pressure. More the dissolved solute particles greater will be the deficit in diffusion pressure and lesser the number of solute particles lesser will be deficit in diffusion pressure. One more component is the wall pressure which is equal and opposite to the turgor pressure. Mathematically expressed DPD is equal to OP - TP. Water moves from an area of lower DPD to an area of higher DPD.

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

If cell A with DPD $5$ atm is surrounded by many cells with DPD $4$ atm then.

  1. The net movement of water will be from cell A to the surrounding cells

  2. Net movement of water will be into cell A from the surrounding cells

  3. Water will not move at all

  4. Water movement will depend on other unknown factors
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Water moves from a region of lower DPD (higher water potential) to a region of higher DPD (lower water potential). Since cell A has a DPD of 5 atm and the surrounding cells have a DPD of 4 atm, water will move from the surrounding cells into cell A.

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

The actual pressure with which water enters into cell is called

  1. DPD

  2. OP

  3. WP

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

The actual pressure with which water enters into a cell is 'Diffusion Pressure Deficit' or DPD. It can be calculated as the difference in the osmotic pressure and turgor pressure. Osmotic pressure causes movement of water into the cell and develops because of the solutes dissolved in the solution of cell sap. On the other hand the turgor pressure is an opposing force, which works in the direction opposite to the movement of water and prevents entry of water into the cell. Turgor pressure develops because of the entry of water into the cell. 

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

The osmotic parameter determining flow of water from one cell to another is

  1. Osmotic pressure

  2. Turgor pressure

  3. Diffusion pressure deficit

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

Diffusion pressure deficit (DPD) is a negative measurement to understand the flow of water from one cell to another. It is important to note that we are considering deficit in diffusion pressure and not diffusion pressure. As a rule, water always flows from lower DPD to higher DPD. This is because lesser the dissolved salts, lesser will be the deficit (so low DPD) and more the dissolved salts more will the deficit (so high DPD). As you can guess water will flow from a region of lower dissolved salts (i.e., low DPD) towards a region of more dissolved salts (i.e., higher DPD).