Tag: tissues: plant tissues

Questions Related to tissues: plant tissues

Which of the following statement (s) is/are true?
(A) Uneven thickening of cell wall is characteristic of sclerenchyma.
(B) Periblem forms cortex of the stem and the root.
(C) Tracheids are the chief water transporting elements in gymnosperms.
(D) Companion cell is devoid of nucleus at maturity.
(E) The commercial cork is obtained from Quercus suber.

  1. A and D only

  2. B and E only

  3. C and D only

  4. B, C and E only


Correct Option: D
Explanation:

The cortex of the root and shoot is formed from the periblem. The cortex is the outermost layer on the stem or roots of plants. Cork which is used commercially as bottle stoppers, bulletin boards, coasters, insulation, sealing for lids, flooring, gaskets for engines etc. is obtained from Quercus suber, commonly called as the cork oak, a medium-sized, evergreen oak tree. Since the vessel elements are absent in most gymnosperms, the tracheids form the main elements of xylem that help in transporting water and minerals.

Therefore, the correct answer is option D.

Grittness in pear is due to the presence of 

  1. Brachy sclereids

  2. Astro sclereids

  3. Ostero sclerids

  4. macor sclerids


Correct Option: A
Explanation:

Sclereids are reduced form of sclerenchyma cells with thick and lignified walls. Grittiness in pear is due to the presence of stone cells called as sclereids. The presence of numberous brachy sclereids makes the texture of pear gritty. The brachy sclereids are isodiametric in shape.

Thus, the correct answer is 'Brachy sclereids'.

Stereome comprises

  1. Sclerenchyma

  2. Collenchyma

  3. Non-living cells of vascular tissues

  4. All of the above


Correct Option: D
Explanation:

Stereome is a mechanical tissue which is formed due to polysaccharide deposition. This is seen in sclerenchyma, collenchyma and all non-living cells of vascular tissues. The deposition of polysaccharides thickens the cell walls in all the three tissue types. Collenchyma is formed due to the deposition of cellulose and is a living tissue. Sclerenchyma is formed due to the deposition of lignin and is a dead permanent tissue.

So, the correct answer is 'All of the above'.

What chemical substance is deposited in the secondary wall of sclerenchyma?

  1. Myelin

  2. Lignin

  3. Lymph

  4. Collagen


Correct Option: B
Explanation:

  • Sclerenchyma cells are simple permanent tissue which is composed of dead cells and has secondary cell walls thickened with cellulose and usually impregnated with lignin. It serves two major functions protection and support.

Therefore, the correct answer is option B.

Leaves of Victoria regia are rigid due to

  1. Stellate parenchyma

  2. Stellate sclerenchyma

  3. Osteosclereids

  4. Macrosclereids


Correct Option: B
Explanation:

Victoria regia belongs to the genus of water-lilies, from the family Nymphaeceae and inhabits in the still waters of all the rivers of the South American continent. These are characterized by the presence of  very large green leaves that are orbiculate, peltate, flat with their margin elevated all around and floating on water surface. The leaves borne on long foot stalks  are radiately and reticulately ribbed and the venation of lamina corrugated involute. A cross section reveals the presence of stellate sclerenchyma cells. The sclerenchyma cells with thick nonelastic walls provide the strength and support for these vast leaves

So, the correct answer is 'Stellate sclerenchyma'

The hypodermis present in maize stem is

  1. Parenchymatous

  2. Collenchymatous

  3. Sclerenchymatous

  4. Meristematic


Correct Option: C
Explanation:

Hypodermis is a part of the outer protective layer in the plant. It is placed below the epidermis.
The hypodermis is especially well developed in plants of arid regions and in those with shallow root systems. It also deters the entrance of soil microorganisms. Monocot stem's hypodermis is a region that lies immediately below the epidermis. It is represented by a few layers of compactly arranged sclerenchyma cells. Maize is a monocot.
Thus, the correct answer is option C.