Test: Plant Tissue - 2 - NEET MCQ

Collenchyma occurs in climbing stems. Collenchyma occurs in the stem and petioles of dicot herbs. Due to deposition of pectin, it has high water retaining capacity. Since pectin appears at the angles, it becomes a spongy tissues.

The is "mechanical tissue". Both sclerenchyma and collenchyma are mechanical tissues, but sclerenchyma contains lignin. Hence the simple mechanical tissue without lignin is chollenchyma. 

Collenchyma cells are mechanical tissue, they possess thickening of corners of cells.

Collenchyma tissue is composed of elongated cells with irregularly thickened walls. They provide structural support and flexibility to the growing stems.

Sclerenchyma is the supporting tissue in plants. It is composed of dead cells which is completely devoid of protoplasm.

Therefore, the correct answer is option A.

Root cap is parenchymatous, cap-like multicellular structure that covers the root apical meristem. It secretes mucilage to lubricate the path of root in soil. Shoot cap is not found in any plant. Shoot apex has shoot apical meristem which is conical structure and gives rise to primordial leaves at intervals. The primordial leaves in turn protect the shoot apex. Calyptra is the protective covering of sporogonium which is sporophytic plant body of bryophyte. Thus, the correct answer is option D.

The tissue is elastic, extensible and has capacity to expand and gives a tensile strength to the organ.

Collenchyma is simple living tissue with thick non-lignified walls and uneven deposition of cellulose and pectin. They are derived from parenchyma and are present in groups under epidermis to provide flexible support to the growing plant's organs and thus are present in young dicot stem, pedicel, and petioles, not in leaf base and roots, which are not the growing part. It is not present in monocots.

Collenchyma is a type of plant tissue in which cells are elongated in shape with the irregularly thickened primary cell wall. It provides mechanical support to the plant.

Collenchymatous cells are present at the periphery of herbaceous stems, petioles and the ribs of some leaves. They are also present in floral parts, fruits and aerial roots.,

Collenchyma develops from the ground meristem or procambium.

Types of collenchyma are

(a) Angular: The thickening materials deposit at the angles or corners of the cells where several cells meet e.g., petioles of Cucurbita, beta etc.

(b) Lamellar: The thickening material deposits heavily on the tangential walls of the cell than the radial walls e.g. stem of Sambucus.

(c )Lacunar : The thickening material deposits at those places of the cell wall which are in direct contact with the intercellular spaces. e,g, petioles of Salvia, Malva.

(d) Annular: In this type, the cell lumen more or less appears to be circular. This is mature tissue where cell shape changes with heavy deposits of pectin and hemicellulose in walls.

Thus, the correct answer is option D.

Sclerenchymatous cells and their cell walls:
- Sclerenchyma is a type of plant tissue that provides structural support to the plant.
- Sclerenchymatous cells have thick and rigid cell walls, which make them strong and durable.
- The cell walls of sclerenchymatous cells contain a large percentage of various substances, including lignin, cellulose, pectin, and silica.
- However, the largest percentage is typically attributed to lignin.
Lignin:
- Lignin is a complex polymer that gives strength and rigidity to the cell walls.
- It is a phenolic compound that is highly resistant to degradation.
- Lignin deposition in the cell walls increases with maturity, making the cell walls harder and less flexible.
- Lignin provides mechanical support to the plant and helps prevent collapse of the cell walls.
Other substances in sclerenchymatous cell walls:
- Cellulose: Cellulose is another important component of the cell walls, but its percentage is generally lower compared to lignin.
- Pectin: Pectin is a polysaccharide that plays a role in cell adhesion and cell wall flexibility. However, its percentage in sclerenchymatous cell walls is relatively low.
- Silica: Silica is also present in some plant tissues, particularly in certain grasses and horsetails. However, its occurrence in sclerenchymatous cell walls is less common.
Conclusion:
- Sclerenchymatous cells have thick and rigid cell walls.
- The cell walls contain a large percentage of lignin, which provides strength and rigidity.
- While cellulose, pectin, and silica may also be present, their percentages are generally lower compared to lignin.

• Bast fibres are collected from the phloem.
• These fibres are commercial fibres.
• These are made up of sclerenchymatous cells.
• These fibres are found in secondary phloem.
• They provide mechanical support to sieve elements.

Bast fibres are obtained from the leaves of Corchorus.

Sclerenchyma is a simple permanent tissue which is mainly composed of dead cells. The walls consist of cellulose, hemicellulose and lignin. These are the principal supporting cells in plant tissues that have ceased elongation. 
Sclerenchyma fibres are of great economical importance, since they constitute the source material for many fabrics (flax, hemp, jute, ramie).
So, the correct answer is option D.

Tissue which develops more due to the scarcity of water is sclerenchyma. Sclerenchyma is the supporting tissue in plants. Two types of sclerenchyma cells exist: fibres and sclereids. Their walls consist of cellulose, hemicellulose, and lignin. Sclerenchyma cells are the principal supporting cells in plant tissues that have ceased elongation. Sclerenchyma is composed of dead cells with extremely thick cell walls -secondary walls that make up to 90% of the whole cell volume.
Thus, the correct answer is option A.

Sclerenchyma cell is a simple permanent tissue which is mainly composed of dead cells. It is the hard, thick walls that make sclerenchyma cells important strengthening and supporting elements in plant parts that have ceased elongation. Their cell walls contain, besides cellulose, a high proportion of lignin. It forms a protective coating on seeds and nuts. Since sclerenchyma cells are dead at maturity, it does not contain plastids. Parenchyma and collenchyma cells are living cells which have plastids.

• This hormone plays a vital role in the development of seed, dormancy, maturation, vernalization, and antagonist to gibberellins.
• Ethylene mainly functions for the ripening of fruits and gibberellins for the growth of stem whereas cytokinin help in the production of new leaves, lateral shoots, and adventitious roots.

• The body of the ovule in the orthotropous is upright.
• The chalaza, micropyle, and hilum lie in one straight line.
• This is the most primitive ovule.

The ovule in which micropyle lies at one end while chalaza and hilum lie at the opposite end is called an orthotropous ovule.

The analogous cells adjacent to the sieve cells of gymnosperms are called as albuminous cells. They are long, slender, conducting cells of the phloem. Sieve cells are found in gymnosperms. Albuminous cells are also called as Strasburger cells. They lack starch, thus making it possible to differentiate them from phloem parenchyma.
Therefore, the correct answer is option B.

Cambium cells,root hairs and companion cells are living cells.

Hence (B) is the correct answer.

Tracheids are the chief water-conducting elements in gymnosperms and seedless vascular plants. They can also be found in angiosperms. Tracheids are elongated cells, closed at both ends. The walls are opened by numerous pits that are, depending on their origin, either round, oval, gap- or groove-shaped. Bordered pits are especially common in the tracheids of some gymnosperms.
Correct option is A. 

Vessels are limited in their growth and are joined end to end to form continuous tubular structures with perforations in their cross walls. Tracheids are elongated and non-perforated. They have only pit pairs at the regions of union with other tracheids.  
Thus, the correct answer is option B.

Translocation occurs within a series of cells known as the phloem pathway, or phloem transport system, with phloem being the principal food-conducting tissue in vascular plants. Nutrients are translocated in the phloem as solutes in a solution called phloem sap.

Angiospermic phloem is a composed of four elements namely, sieve elements, companion cell, phloem fibres and phloem parenchyma. The pteridophytes and gymnopserms have sieve cells and phloem parenchyma only; however few gymnosperms have phloem fibres also. Thus, angiosperms have companion cells which are absent in pteridophytes and gymnosperms.
Companion cells are structurally and functionally associated with sieve tube elements which are not present in pteridophytes and gymnosperms; thus no companion cells. Enzymes are not present in phloem. Function of phloem is to food conduction through pressure flow mechanism, not endocytosis which is defined as active import of molecules by cells.
Thus, the correct answer is option C.

Phloem is a conducting tissue that transports food materials, usually from leaves to other part of the plants. In phloem, sieve elements arranged one above the other in distinct linear rows and have sieve plates (oblique or transverse perforated septa) on their end walls. These are associated with companion cells.

Tracheids are elongated cells in the xylem of vascular plants that serve in the transport of water and mineral salts. Tracheids are Cycas one of two types of tracheary elements, vessel elements being the other. Tracheids, unlike vessel elements, do not have perforation plates.

Sieve tube cells does not have lignin in their walls whereas the cell walls of vessels have many secondary thickenings in their walls.
Therefore, the correct answer is option B.

The sieve tubes are closely associated with companion cells which provide strength and nourishment for the general metabolic functions. It is present only in angiosperms. A vessel element or vessel member is one of the cell types found in xylem, the water conducting tissue of plants. Vessel elements are typically found in flowering plants (angiosperms) but absent from most gymnosperms such as conifers.

Dicot root – phloem parenchyma is present.
Dicot leaf – Phloem parenchyma is present.
Monocot stem – phloem parenchyma is absent.
Dicot stem – Phloem parenchyma is present.
So, the correct answer is 'Monocot stem'.

Sclereides are much harder due to presence of higher amount of lignin and are grouped according to their various shapes.
Macrosclereids are rod shaped elongated sclereids which are present in leaves, outer seed coat and serve to restrict water uptake by hard-seeded legumes.
Brachysclereids resemble parenchyma cells in shape they are non-living stone cells with empty lumen in the center surrounded by secondary cell walls. They form the grit in pear fruit. 
Osteosclereids which are bone or barrel shaped with dilated ends which are present in leaf of Hakea. 
The inner most germinative layer of epidermis is called as the malpighian layer and the cells are malpighian cells ability to divide.
Therefore, the correct answer is option A.

Option 1: Sclereids, Tracheid, Vessel member - CORRECT

• Sclereid is a type of sclerenchyma tissue. The cell wall of the sclereid is thick and lignified. This is due to secondary wall thickening.
• Tracheids are xylem elements. The cell wall of tracheids are thick and lignified.
• Vessel members are xylem elements that are broad and cylindrical with lignified walls and a wide cavity.
• Thus all the 3 cell types have thick and lignified cell walls.

Option 2: Collenchyma, Sclereid, Guard Cell - INCORRECT

• ​Collenchyma is a simple living tissue with thick cellulosic walls with thickenings at the corner of the cells.
• Sclereid is a type of sclerenchyma tissue. The cell wall of the sclereid is thick and lignified.
• Guard cells govern the stomatal movement. The cell walls of guard cells are made up of cellulose, xyloglucan and pectins.

Option 3: Endodermis, Sclerenchyma, Sieve Cells - INCORRECT

• ​The endodermis is the innermost layer of the cortex of a root.  The radial walls of the endodermis bear the Casparian strip that is made up of suberin.
• Sclerenchyma is a simple permanent dead tissue. The walls of sclerenchyma are made up of primary cellulosic walls along with secondary thickening made up of lignin. 
• Sieve cells are phloem elements. It comprises non-lignified cellulosic cell walls.

Option 4: Trichome, Tracheid, Vessel member - INCORRECT 

• Trichomes are unicellular or multicellular appendages seen in plants. These are the extensions of epidermal cells.
• Tracheids have thick and lignified cell walls.
• Vessel members like tracheids have thick and lignified cell walls.

So the correct answer is option 1.

Sieve tubes are long, slender tube shaped structures which are arranged in longitudinal manner with perforated end walls that make sieve plates. The sieve area or sieve plates are the depressed areas in their oblique end walls with cluster of pores that connect the protoplast of adjacent sieve element
So, the correct answer is 'Oblique and in end wall'.

Tracheid is the fundamental single elongated dead cell of xylem. During cell wall thickening, deposition of lignin covers the whole primary cell wall of tracheid, except at gaps termed as 'bordered pit-pairs'. The pit pairs represent the small regions of the unlignified primary wall from two adjacent cells and are concentrated at end walls between cells, forming a pitted region called as pitted end walls. A pit pair shares a common membrane of the primary wall and middle lamella and the raised wall around the pit aperture serve as a border. The xylem which is formed first is present is termed as protoxylem, while metaxylem is the xylem that develops afterwards. Protoxylem is characterised by the presence of annual, spiral, scalariform vessels and no tracheids, while metaxylem has reticulated and pitted vessels and some tracheids.