Botany and Plant Science

• Sclereids or stone cells are a type of reduced sclerenchyma cells.
  
• These stone cells form hard structures such as seed coats and nut shells and provide support to the soft tissues.
• Their cell wall is highly thickened and lignified which form small bundles of durable layers of tissues.
• The presence of numerous stones cells that makes pear and guava have a gritty texture is brachysclereids (unbranched, short and isodiametric with pits).
• The stone cells in tea leaves that make it tougher are astrosclereids (branched as star-shape).

Sclereids are a reduced form of sclerenchyma cells with highly thickened, lignified cellular walls that form small bundles of durable layers of tissue in most plants. 

Vascular tissues concerned in the transportation of water, mineral and food.

Phloem is a vascular tissue or conducting tissue, meant for the translocation of organic solutes or food.

Collenchyma is a simple permanent living mechanical tissue, provides elasticity to the young stems.

Mechanical tissues are the rigid cellular tissues, provides elasticity, flexibility to the different parts of the plant body. These are called stereome. So, the correct answer is 'Mechanical tissue’.

A. Sclerenchyma is known as the supporting tissue of the plants which make the plant hard and stiff as their cell wall is made up of cellulose, hemicellulose and lignin.

Parenchyma tissue possess cells with a wide lumen. In aquatic plants, parenchyma cells possess large air cavities, which provide buoyancy to the plant. It enables the plant to float. Hence, option B is incorrect. 
Collenchyma tissue contains cell with wide lumen. Hence, option C is incorrect.  
Tracheids possess spacious lumen, which extends throughout the length. Hence, option D is incorrect. 
Sclerenchyma tissue possess long and narrow cells with narrow lumen. Hence, option A is correct.  

A. sclerenchyma fibers are long, narrow spindle-shaped sclerenchyma cells having tapering end walls.

B. phloem fibers are sclerenchyma fibers present in the phloem, also called bast fibers.

C. libriform fibers are the typical xylem fibers with thick walls and simple pits.

D. fiber tracheids are xylem fibers intermediate between tracheids and typical sclerenchyma fibers.

so the correct answer is ‘phloem fibers’.

Sclerenchyma cells are characterized by relatively thick, lignified secondary cell walls. All plant cells initially have only a primary wall made predominantly of cellulose. As sclerenchyma develops, a secondary wall with a high proportion os lignin is deposited inside a primary wall.

Bast is the term used for the fibres of phloem. These fibres are tough and resistant with a narrow lumen and secondary walls deposited with lignin. These are dead elongated cells of sclerenchyma tissue. Examples include jute fibres. 

Pericycle is the outermost layer of the stele. Stele is composed of all tissues inside of the endodermis. Structure of pericycle differs in monocots and in dicots. In dicots, pericycle is in the form of isolated strips of sclerenchyma cells, which are lignified. Each patch is associated with phloem of vascular bundle. Such, pericycle is called as hard bast. 
Epiblema are special epidermal cells present in rootlets. They are specially adapted for absorbing liquids. Phellem is outermost layer of cork cambium which is suberised. 
Astrosclereids is a type of sclereid which is a large, radially branched structure. 
Thus, the correct answer is option C.

Hypodermis is present in both dicot and monocot stems. In case of dicots, the hypodermis is made up of collenchyma cells and those present in monocots is made up of sclerenchymatous cells.

Macrosclereids are elongated sclereids. Sclereids are the reduced form of sclerenchyma. It is usually found in the outer layer of seed coat of legumes. These cells are responsible for restricting water uptake by hard seeded legumes. 

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.

• 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.

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

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.