1.How does collenchyma is differ from chlorenchyma?

Ans: Collenchyma is differ from chlorenchyma by;

 Collenchyma:They are the living cells which are somewhat elongated. Cells of this tissues possess localized thickening on the cell wall, particularly at the corner. It occurs in the herbaceous dicotyledons e.g. sunflower, gourd, etc.

 Chlorenchyma: In the leaves, the palisade cells are long and contain chloroplast in them. They help in photosynthesis and are essentially parenchyamatous due to their contain chlorophyll.

 

2.Name the components of secondary phloem.

Ans: The components of secondary phloem are sieve tubes, companion cells, phloem parenchyma and bast fibres.

 

3.Name the two types of sclerenchyama.

Ans: The two types of sclerenchyama are ;

1.Fibres

2.Sclereids

 

4.From where do the secondary meristems appear?

Ans: The secondary meristem appear in root and stem.

 

5.In which types of stem, the vascular bundles are arranged in the ring?

Ans: In dicot stem, the vascular bundles are arranged in the ring.

 

6.Which types of meristems can be classified on the basis of position in the plant body?

Ans: Following meristems can be classified on the basis of position in the plant body;

a.Apical meristem

 b.Intercalary meristems

c.Lateral meristems

 

7.Which tissue is responsible for transport of food in plants?

Ans: Phloem is responsible for transport of food in plants.

 

8.Give the names of complex tissues.

Ans: The names of complex tissues are;

a.xylem

b.phloem

 

9.From where the secondary meristem arises?

Ans: There are two types of secondary meristems, these are also called the lateral meristems because they surround the established stem of a plant and cause it to grow laterally (i.e., larger in diameter).

Vascular cambium, which produces secondary xylem and secondary phloem. This is a process that may continue throughout the life of the plant. This is what gives rise towood in plants. Such plants are called arborescent. This does not occur in plants that do not go through secondary growth (known as herbaceous plants).

Cork cambium, which gives rise to the periderm, which replaces the epidermis.

 

 

10.Name the components of secondary phloem.

Ans: The components of secondary phloem are sieve tubes, companion cells, phloem parenchyma and bast fibres.

 

Short questions:

1.How xylem differs from phloem?

Ans: Xylem differs from phloem by;

Xylem:

1.Xylem transports and stores water and water-soluble nutrients in vascular plants.

2. Xylem consists of dead cells with no end walls, which contain lignin to form stiff tubes. They are impermeable, and are strengthened with fibres. 

 

 

Phloem:

 

1.Phloem is responsible for transporting sugars, proteins, and other organic molecules in plants.

 

2.Phloem consists of living cells lined with cytoplasm, with walls made of cellulose and perforated end walls called sieve plates. They are permeable, and are surrounded by companion cells.

 

2.What do you know about apical meristem?

Ans: The meristems loacated at the apices or the growing points of main and lateral shoots and roots are called apical meristems. They include both promeristems and primary meristems.

 

3.Describe the nature of secretary cells in plants.

Ans:The nature of secretary cells in plants is to secrete gums, etc.

 

4.Give the anatomical differences between dicot root and stem.

Ans: The anatomical differences between dicot root and stem are given below;

 

5.Which features help to identify whether the given material is a T.S of root or stem?

Root	Stem
1.Epidermis usually has no cuticle layer and stomata.	1.Epidermis is always covered with a thick or thin layer of cuticle.
2.The epidermis contains unicellular root hairs.	2.If the hair is present, it is multicellular.
3.Cortex is broad and well developed.	3.Cortex is only present in dicot stem and it is narrow.
4.Endodermis is distinct.	4.Endodermis is not distinct.
5.Pericycle is usually single layered.	5.In a dicot stem, pericycle is usually multilayerd.
6.The vascular bundles are of radial type.	6.The vascular bundles are conjoint and collateral type.
7.Exarch xylem is the characteristic features of the root.	7.Endarch xylem is the characteristics features of the stem.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Ans: Following features help to identify whether the given material is a T.S. of the root or stem;

 

 

Long questions:

1.Describe the process of secondary growth in dicot stems.

Ans: The process of secondary growth in dicot stems is given below;

On the basis of the activities of cambium and cork cambium it can be discussed under following two types;

A.Activity of cambium:

1.Formation of cambium ring in dicot stem cambium is present between xylem and phloem. During secondary growth the cambium, some cells of medullary ray also becomes active form in intrafasicular cambium. Intra and inter fasicular cambium unite together to form cambium ring.

2.Formation of secondary tissues: When the cambium ring active as it starts cutting of new cell, both internally and externally. The cut off cells get differentiated into elements of phloem and inner side is modified into the elements of xylem.

3.Secondary medullary ray: Certain cell of cambium instead of forming secondary xylem and phloem form some narrow bands of living parenchyma cells. These form 2 or 3 layers thick radical rows passing through secondary xylem and phloem are called secondary medullary rays.

4.Annual ring: The age of the plant can be approximately determined by cutting the number of annual rings where dendrochronology is the branch of anatomy which deals with determining the age of tree.

5.Wood: In the old tress, the secondary wood is differentiated into a centrally situated darker and harder called heart wood and outer light coloured zone called sap wood.  

Fig; diagram showing stages in the sec. growth of a dicot stem.

B.Activity of the cork-cabium: The marked increased in the diameter in the stem brought about by the secondary thickening exerts great pressure on the outer tissues cause rupture of the cortex and epidermis as a result the outermost layer of the cortex next to epidermis become meristematic and begins to divide the process known as cork- cambium.

 

2.Describe the various type of simple tissue found in plants. Mention their functions.

Ans:

Simple permanent tissue: These tissues are the group of cells which are similar in origin, form and  function. These are also mainly three types;

1.Parenchyma:

 It is most common permanent tissues. They are thin walled living cells which are oval, spherical or polygonal in shape. They contain large vacuole. The cells have intercellular spaces in between them which may small or big. This tissue is generally present in almost all the organs. They are of following types;

a.Prosenchyma: In some cases the parenchymatous cell become long and taper at either end such tissues is called prosenchyma.

b.Aerenchyma: Some cells have wide air spaces between them called aerenchyma.

c.Chlorenchyma: In the leaves, the palisade cells are long and contain chloroplast in them. They help in photosynthesis and are essentially parenchyamatous due to their contain chlorophyll.

Functions of parenchyma:

1.Parenchymatous cells help in photosynthesis. e.g palisade cells of leaf.

2.It servers mainly for the storage of food materials in the form starches, proteins, oils and fats.

3.In the fleshy stems of leaves, it helps in store water.

B.Collenchyma:

 

Collenchyma are the living cells which are somewhat elongated. Cells of this tissues possess localized thickening on the cell wall, particularly at the corner. It occurs in the herbaceous dicotyledons e.g. sunflower, gourd, etc.

Funcations:

1.It gives mechanical strength to the organs.

2.It also manufacture sugar and starch.

3.In some plants, collenchyma cell regain the power to divide.

C.Sclerenchyma:

It consists of long, narrow, thick walled and lignified cells which are dead cells and do not perform any metabolic activities. They are found abundantly in plants and occurs in patches or in definite layers.

Functions:

1.They give strength and rigidity to plant body.

2.They also enable it to withstand mechanical strength.

Sclerenchyma are of two types;

1.Fibres: Fibres are long and tapering at ends which are thick walled cells. The fully developed fibres are always dead. They are present in the xylem of stems and roots, testa of various seeds. Its main function is to give mechanical strength.

2.Sclereids: They are extremely thick walled and may be spherical, oval, cylindrical, etc. They are generally found in hard parts of plant body sometimes in the pulp of fruits. They are be classified into four main types on the basis of their shapes. Its main function is to provide local mechanical strength.

 

 

 

3.What are complex tissues? Describe with suitable examples any two of them.

Ans: Complex tissues are made up of more than one type of cells and they work together as a unit. They transport water, salt and prepared food material to various parts of the plant body.

Complex tissues are of two types.

1.Xylem

2.Phloem (bast)

1.Xylem:

Xylem or wood is a conducting tissue and is composed of elements of different kinds. They are:

Tracheids

Vessels or tracheae

Xylem parenchyma

Xylem sclerenchyma

Tracheids:

These are elongated cells with sloping walls enclosing a large empty cavity. Cell walls are thickened with lignin. The cells are dead.

 

 

Vessels or trachea:

These are cylindrical tube-like structures formed by a row of cells placed end to end. The transverse walls between the cells are almost dissolved forming a continuous channel or water-pipe. The cells are dead.

Xylem parenchyma:

These are made up of parenchymatous cells. They are thin walled and are living.

Xylem sclerenchyma

These are sclerenchymatous cells and form the wood in older plants. The cells are dead.

 

4..Discuss the structure, locations and functions of the simple permanent plant tissues.

Ans:

Simple permanent tissue: These tissues are the group of cells which are similar in origin, form and  function. These are also mainly three types;

1.Parenchyma:

 It is most common permanent tissues. They are thin walled living cells which are oval, spherical or polygonal in shape. They contain large vacuole. The cells have intercellular spaces in between them which may small or big. This tissue is generally present in almost all the organs. They are of following types;

a.Prosenchyma: In some cases the parenchymatous cell become long and taper at either end such tissues is called prosenchyma.

b.Aerenchyma: Some cells have wide air spaces between them called aerenchyma.

c.Chlorenchyma: In the leaves, the palisade cells are long and contain chloroplast in them. They help in photosynthesis and are essentially parenchyamatous due to their contain chlorophyll.

Functions of parenchyma:

1.Parenchymatous cells help in photosynthesis. e.g palisade cells of leaf.

2.It servers mainly for the storage of food materials in the form starches, proteins, oils and fats.

3.In the fleshy stems of leaves, it helps in store water.

B.Collenchyma:

 

Collenchyma are the living cells which are somewhat elongated. Cells of this tissues possess localized thickening on the cell wall, particularly at the corner. It occurs in the herbaceous dicotyledons e.g. sunflower, gourd, etc.

Funcations:

1.It gives mechanical strength to the organs.

2.It also manufacture sugar and starch.

3.In some plants, collenchyma cell regain the power to divide.

C.Sclerenchyma:

It consists of long, narrow, thick walled and lignified cells which are dead cells and do not perform any metabolic activities. They are found abundantly in plants and occurs in patches or in definite layers.

Functions:

1.They give strength and rigidity to plant body.

2.They also enable it to withstand mechanical strength.

Sclerenchyma are of two types;

1.Fibres: Fibres are long and tapering at ends which are thick walled cells. The fully developed fibres are always dead. They are present in the xylem of stems and roots, testa of various seeds. Its main function is to give mechanical strength.

2.Sclereids: They are extremely thick walled and may be spherical, oval, cylindrical, etc. They are generally found in hard parts of plant body sometimes in the pulp of fruits. They are be classified into four main types on the basis of their shapes. Its main function is to provide local mechanical strength.

 

5.Describe various components of xylem and phloem.

Ans:The various components of xylem and phloem are;

Xylem is commonly known as wood which is composed of 4 kinds of cells respectively, tracheids, vessels, wood parenchyma and wood fibres.

Xylem are of two types they are protoxylem and metaxylem.

Protoxylem: It is early formed xylem which bears narrow vessels. It is retained only for a short period where fibres are absent or rare.

Metaxylem: It is late formed xylem which bears large vessels. It is retain for long period where fibres often occurs.

Phloems consists of sieve tubes, companion cells, phloem parenchyma, bast fibres. Phloem are of two types primary and secondary phloem.

Primary phloem: It is develop from procambium which is differentiated into protophloem and metaphloem.

Secondary phloem: It is developed from cambium during secondary growth which shows radial differentiation.