Tag: botany

Questions Related to botany

According to histogen theory, epidermis is formed by

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

  1. Dermatogen

  2. Protoderm

  3. Periblem

  4. Plerome

Show answer
Correct Option: A
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'

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

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

  1. Histogen theory

  2. Tunica corpus theory

  3. Meristem theory

  4. Dermatogen theory

Show answer
Correct Option: A
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'

Histogen theory was proposed by

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

  1. Nageli

  2. Schmidt

  3. Hanstein

  4. Wolf

Show answer
Correct Option: C
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'

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

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

  1. Anneau initial

  2. Meristeme medullaire

  3. Promeristeme sporogene

  4. Promeristeme receptaculaire

Show answer
Correct Option: A

DPD is equal to :

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

  1. OP $ \times $ TP (WP)

  2. OP $ + $ TP (WP)

  3. OP $ - $ TP (WP)

  4. TP (WP) $ - $ OP

Show answer
Correct Option: C
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.

Water passes into cell or one cell to another due to 

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

  1. O.P.

  2. D.P.D.

  3. W.P.

  4. Diffusion

Show answer
Correct Option: B
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.

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

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

  1. D.P.D.

  2. O.P.

  3. W.P.

  4. Diffusion

Show answer
Correct Option: A
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.

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

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

  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

Show answer
Correct Option: B

The actual pressure with which water enters into cell is called

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

  1. DPD

  2. OP

  3. WP

  4. Diffusion

Show answer
Correct Option: A
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. 

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

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

  1. Osmotic pressure

  2. Turgor pressure

  3. Diffusion pressure deficit

  4. Hydrostatic pressure

Show answer
Correct Option: C
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).