Tag: absorption of water from the soil

Questions Related to absorption of water from the soil

Rootlets are called as

  1. Tap root

  2. Adventitious roots

  3. Lateral roots

  4. None of the above


Correct Option: C
Explanation:

Rootlets are also called as lateral root and are defined as the small branches of roots that form from the main root and helps the plant for the absorption of water and minerals as they increase surface area.

So, the correct option is 'Lateral roots'.

Root cap regenerated/dead torn cells of root cap are replaced by the activity of

  1. Plerome

  2. Dermatogen

  3. Calyptrogen

  4. Periblem


Correct Option: C
Explanation:
Calyptrogen is the formative tissue found in the growing point of a root, giving rise to the root cap. Calyptrogen, as a rule, is characteristic of monocotyledonous plants. In most dicotyledonous plants, instead of calyptrogen, there is a tissue that also gives rise to the root’s absorbent external piliferous layer; this tissue is called dermatocalyptrogen.
The correct option is 'Calyptrogen'.

In the transverse section of a dicot root.

  1. The protoxylem vessels are present towards the periphery and metaxylem vessels are present towards the centre

  2. The protoxylem vessels are present towards the centre and metaxylem vessels are present towards the periphery

  3. Protoxylem is completely surrounded by the metaxylem vessels

  4. Metaxylem is completely surrounded by protoxylem


Correct Option: A

The multicultural hair-like structures of Salvinia which remain submerged in water are ____________.

  1. Roots

  2. Rhizoids

  3. Leaves

  4. Stem


Correct Option: A

In which of the following organs, growth is subapical?

  1. Shoot

  2. Petiole

  3. Root

  4. Pedicel


Correct Option: C
Explanation:
Roots grow in length only from the ends. The tip of the root is covered by a root cap, which gives protection to the growing tip as it makes its way through the soil. The root has a subapical region, which is divided into three zones. They are, the zone of cell division, the zone of elongation and the zone of cell maturation. The subapical region carries out the growth of the roots.

 Hence, the correct answer is option C.

Root region with thin-walled, small cells having sense cytoplasm is

  1. Region of cell elongation

  2. Maturation region

  3. Proximal to cell elongation zone.

  4. Distal to cell elongation zone


Correct Option: A
Explanation:

The protoplasm of the cell is surrounded by a primary cell wall which is laid down as the cell begins to grow. It is thin and composed of cellulose, hemicellulose and pectic substances. Once growth has ceased a secondary cell wall may form inside the primary cell wall.

So, the correct option is 'Region of cell elongation'.

Main component of middle lamella is?

  1. Mg pectate

  2. Calcium pectate

  3. Calcium carbonate

  4. Calcium oxalate


Correct Option: A
Explanation:

The middle lamella is a pectin layer which cements the cell walls of two adjoining plant cells together. It is the first formed layer which is deposited at the time of cytokinesis. The cell plate that is formed during cell division itself develops into middle lamella or lamellum. In plants, the pectins form a unified and continuous layer between adjacent cells. Frequently, it is difficult to distinguish the middle lamella from the primary wall, especially in cells that develop thick secondary walls. The middle lamella is made up of calcium and magnesium pectates.

So the correct option is 'Mg pectate'.

Consider the following statements.
(a) In a dicot root, the vascular bundles are collateral and endarch.
(b) The inner most layer of cortex in a dicot root is endodermis.
(c) In a dicot root, the phloem masses are separated from the xylem by conjunctive tissue. 
Of the above given statements

  1. (a) is true; but (b) and (c) are false

  2. (b) is true; but (a) and (c) are false

  3. (a) is false; but (b) and (c) are true

  4. (c) is false ; but (a) and (b) are true

  5. (c) is true; but (a) and (b) are false


Correct Option: C
Explanation:

Dicot root shows radial vascular bundles, i.e., vascular bundles arranged in a ring. In this type of vascular bundle, the xylem and phloem are situated at different radii. Xylem is of exarch type, i.e., protoxylem is away from centre and metaxylem is towards centre. Hence, statement (a) is wrong.
The innermost layer of cortex in a dicot root is endodermis. It completely surrounds the stele. It consists of single layer of barrel shaped cells which lack intercellular spaces. Hence, statement (b) is correct. 
In a dicot root, the phloem masses are separated from the xylem by conjunctive tissues. Later, vascular cambium forms from this conjunctive tissue. Hence, statement (c) is correct. 
Thus, the correct answer is '(a) is false; but (b) and (c) are true'.

Passage cells are thin walled cells found in ____________________.

  1. Phloem elements to serve as entry points

  2. Testa of seeds for emergence of embryonal axis

  3. Central area of style for passage of pollen tube

  4. Endodermis of roots to facilitate rapid transport of water from cortex to pericycle


Correct Option: D
Explanation:
Passage cells are thin walled cells present opposite to xylem patches in the endodermis of the root. They are endodermal cells.They are also called transfusion cells. They help in water transport from cortex to pericycle. 
So the correct answer is 'Endodermis of roots to facilitate rapid transport of water from cortex to pericycle'

Velamen tissue is found in ................

  1. Mesophytes

  2. Epiphytes

  3. Hydrophytes

  4. Xerophytes


Correct Option: B
Explanation:
A typical aerial root of epiphytes consists of a specialised outer epidermis of several cell layers, called as the velamen. When mature, these cells are dead and filled with air. The velamen acts as a site for temporary water storage.
So, the correct answer is 'Epiphytes'