Tag: tissues: plant tissues

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Multiple choice botany plant tissues permanent tissues and their types simple permanent tissues tissues: plant tissues

Senescence and death are essential in the function of

  1. Sieve tubes

  2. Companion cells

  3. Both A and B

  4. Xylem and sclerenchyma cells
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Senescence refers to the loss of functional capacity causing a cellular breakdown and metabolic failure. It is a characteristic feature of the period between reproductive maturity and death of a plant or plant part or cell, which ultimately causes cell death. 

A mature sieve tube is composed of vertical cells placed one above other with perforated sieve plates at their lateral walls to serve as the main conducting element of phloem. They lack nucleus but are living cells. 
Companion cells are live cells. They have a prominent elongated nucleus, which compensates for the absence of nucleus in sieve tubes. 
A sclerenchymatous cell is thick walled dead lignified cells without meristematic activity. These cells lack nucleus and protoplasm at their maturity. 
Xylem is a complex tissue and is made up of tracheids, vessels, fibers and parenchyma and serve in the ascent of sap. Except for xylem parenchyma, all other xylem components are dead and lack nucleus and protoplasm at their maturity. Thus, option D is the correct answer. 

Multiple choice botany plant tissues permanent tissues and their types simple permanent tissues tissues: plant tissues

Hard, lignified, thick-walled, long and pointed cells constitute

  1. Parenchyma

  2. Collenchyma

  3. Sclereids

  4. Sclerenchyma
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Sclerenchyma cells have thick lignified secondary walls and often die when mature. It provides the main structural support to a plant. They are long and pointed cells. 

Parenchyma cells have thin primary walls and usually remain alive after they become mature. It forms the filler tissue in the soft parts of plants. 
Collenchyma cells have thin primary walls with some areas of secondary thickening. Collenchyma provides extra structural support, particularly in regions of new growth. 
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. Sclereids are relatively short. 

Multiple choice botany plant tissues permanent tissues and their types simple permanent tissues tissues: plant tissues

Tissue which develops more due to scarcity of water is

  1. Sclerenchyma

  2. Collenchyma

  3. Parenchyma

  4. Meristem
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Parenchyma is a simple living tissue, which is composed of thin-walled polyhedral, isodiametric living cells with sufficient cytoplasm and one or more nuclei. 

Collenchyma is simple living tissue with thick non-lignified walls and uneven deposition of cellulose and pectin. They are derived from parenchyma and serve to impart tensile strength to growing parts. 
Meristem is a simple living tissue with dense cytoplasm and prominent nucleus; they divide and form new cells. 
Parenchyma, collenchymas, and meristem tissues need water to maintain living cytoplasm and nucleus and thereby to perform physiological  functions. 
Sclerenchyma is a dead tissue with thick lignified cell walls, which makes it hard and tough. They lack nucleus and cytoplasm and thus do not need water to maintain their functionality.
So, the correct answer is option A.

Multiple choice botany plant tissues permanent tissues and their types simple permanent tissues tissues: plant tissues

The main function of sclerenchyma is to help in the ___________________.

  1. Conduction of food

  2. Synthesis of food

  3. Exchange of gases

  4. Mechanical support
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Conduction of food from leaves to other parts of the plant is carried out by phloem cells. 
The synthesis of food is carried out by chlorenchyma cells. These are parenchyma cells with chlorophyll pigments. 

Exchange of gasses is carried out by stomata, which are small pores present on leaf epidermis.   
Sclerenchyma is a type of permanent tissue. They are dead, long, thin narrow cells with thickened walls without any internal space. This tissue makes the plant hard and stiff. This aids in mechanical support to plant. 
So, the correct answer is option D.

Multiple choice botany plant tissues permanent tissues and their types simple permanent tissues tissues: plant tissues

Hard, lignified, thick-walled, long and pointed cells in plants are

  1. Parenchyma

  2. Sclerenchymatous fibre

  3. Collenchyma

  4. Sclereids
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Sclerenchyma is the simple permanent tissue. It commonly forms the protective covering of the nuts and fruits but it also forms the ground tissue which supports different  specialized cells. Their walls consist of cellulose, hemicellulose, and lignin. 

Sclerenchyma fibers are of great economical importance since they constitute the source material for many fabrics. Unlike the collenchyma, mature sclerenchyma is composed of dead cells with extremely thick cell walls that make up to 90% of the whole cell volume. It is the hard, thick walls that make sclerenchyma cells important strengthening and supporting elements in plant parts that have ceased elongation. Fibres or bast are generally long, slender, so-called parenchymatous cells, usually occurring in strands or bundles. Such bundles or the totality of a stem's bundles are colloquially called as fibres. 
So, the correct answer is option B.

Multiple choice botany plant tissues permanent tissues and their types simple permanent tissues tissues: plant tissues

Hard, lignified, thick, walled, long and pointed cells in plants are

  1. Parenchyma

  2. Sclerenchymatous fibre

  3. Collenchyma

  4. Sclereids
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Parenchyma is thin walled, polyhedral, isodiametric, mostly non-lignified, soft living cells with sufficient cytoplasm and one or more nuclei. 

Collenchyma is prismatic or elongated (with pointed ends) cells with thick non-lignified walls; the young cells are elastic while the mature ones are hard and brittle. 
Sclerenchyma is thick walled dead lignified cells, they are hard and elastic. The sclerenchyma cells are divided into two groups namely fibers and sclereids. Sclerenchymatous fibers are branched/unbranched, long, hard, pointed cells with tapering ends, thick walls, and narrow lumen. 
Sclereids are isodiametric, hard cells (due to the presence of higher amount of lignin) with a narrow lumen and are grouped according to their various shapes. 
So, the correct answer is option B.

Multiple choice botany plant tissues permanent tissues and their types simple permanent tissues tissues: plant tissues

Plastids are absent in

  1. Parenchyma

  2. Mesophyll

  3. Sclerenchyma

  4. All of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

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.

So, the correct answer is option C.

Multiple choice botany plant tissues permanent tissues and their types simple permanent tissues tissues: plant tissues

Sclereids or stone cells are modified form of

  1. Collenchyma

  2. Sclerenchyma

  3. Fibers

  4. Xylem vessels
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Sclereids or stone cells are a reduced form of sclerenchyma cells. It has highly thickened, lignified cellular walls that form small bundles of durable layers of tissue in most plants. They are type of sclerenchyma cell that differs from the fibre cell by not being greatly elongated. Often occurs singly (an idioblast) or in small groups, giving rise to a gritty texture in, for instance, the pear fruit, where it is known as a stone cell. May also occur in layers, for example in hard seed coats. A type of cell with thick cell walls, consisting of lignin, that is commonly found on the outer 'skin' of fruits. So, sclereids or stone cells are modified sclerenchyma.

So, the correct answer is option B.

Multiple choice botany plant tissues permanent tissues and their types simple permanent tissues tissues: plant tissues

Sclereids and stone cells are modified

  1. Collenchyma

  2. Sclerenchyma

  3. Fibres

  4. Xylem vessels
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Sclerenchyma is composed of dead tissue which mainly acts as protective coating on fruits and nuts. The reduced form of sclerenchyma cells with highly thickened, lignified cellular walls are known as sclereids. It forms small bundles of durable layers of tissue in most of the plants. 

Stone cell is a type of sclerenchyma cell that differs from the fiber cell by not being greatly elongated. Often occurs singly or in small groups, giving rise to a gritty texture in, for instance, the pear fruit, where it is known as a stone cell. May also occur in layers, for example in hard seed coats. So, sclereids and stone cells are modified sclerenchyma.
Thus, the correct answer is option B.

Multiple choice botany plant tissues permanent tissues and their types simple permanent tissues tissues: plant tissues

Senescence and death are essential in the function of

  1. Sieve tubes

  2. Companion cells

  3. Both A and B

  4. Xylem and sclerenchyma cells
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Senescence is also known as aging. It leads to metabolic degradation. It is the characteristic feature of the period between reproductive maturity and death of a plant or plant part or cell.

A mature sieve tube is composed of vertical cells placed one above other with perforated sieve plates at their lateral walls to serve as the main conducting element of phloem. They lack nucleus but are living cells. 
Companion cells are live cells. They have a prominent elongated nucleus, which compensates for an absence of nucleus in sieve tubes. 
The sclerenchymatous cell is thick walled dead lignified cells without meristematic activity. These cells lack nucleus and protoplasm at their maturity. 
Xylem is a complex tissue and is made up of tracheids, vessels, fibers, and parenchyma and serve in the ascent of sap. Except for xylem parenchyma, all other xylem components are dead and lack nucleus and protoplasm at their maturity. Thus, option D is the correct answer.