3 Biology -- Plant Anatomy

1. What are the functions of Parenchyma, Sclerenchyma and Collenchyma?

1 Answers

Functions of parenchyma :

1. Parenchymatous cells that contain chloroplasts are the main sites of photosynthesis.

2.It serves mainly for the storage of food material in the form of starches, proteins, oils and fats. The parenchymatous tissues in the root and stem tubers are its good examples.

3.In aquatic plants, parenchyma cells (aerenchyma) have lots of spaces that store air to keep them floating and facilitate exchange of gases

4. In fleshy stems and leaves, parenchyma cells store water e.g. Opuntia, Euphorbia sp., Aloe,etc.

5. Various secretory organs of plants are made up of parenchymatous cells that secrete various useful products like oils, nectar, resin, etc.

6.In many aquatic plants, parenchyma helps in mechanical support.

Functions of collenchyma :

1. It gives mechanical strength to the organs and resists the bending and pulling actions of wind.

2.It prevents the leaves from the tearing effect of wind.

3. It also manufactures a small amount of starch by the process of photosynthesis.

4.In some plants, collenchyma cells become thinly walled and regain the power to divide.

5.It helps in the storage of some amount of foods.

Functions of schlerenchyma :

1. It gives the mechanical support to the various parts of a plant.

2.It saves the plants from bending, tearing and shearing likely to cause by the environmental factors.

3. It helps in the stiffness to the parts of a plant.

4. It forms the protective coverings in many legume seeds.

5. It provides the gritness of fruits in the plants like guava, pear, etc.

Describe about the structure of Parenchyma, Sclerenchyma and Collenchyma

Mention the role of cuticle.

Cuticle is the outermost waxy/hydrophobic layer made up of cutin; it's main function is to prevent the loss of water in form of water vapor through the epidermis. It also helps in reduction of transpiration in the xerophytic plants to prevent water loss and provides protection against desiccation.

What is the function cortex?

Cortex, tissue of unspecialized cells, is located between the epidermis and the vascular tissue in the plants . It helps in the transportation of water and minerals to the center or core of the root through the process of diffusion.

Give one example of stem with conjoint and collateral vascular bundle.

All dicot and monocot plants are the examples of plants with conjoint and collateral vascular bundle.

Typical eg: helianthus , zea mays , pisum sativum. Etc

Give one example of scattered vascular bundle in the stem.

Maize aka Zea mays

What are Annual rings?

Annual rings are the rings arranged in concentric forms in the bark of the tree, their numebr represmts the age of the tree whereas their thickness depends upon the season that the tree has lived through.

Define cambium.

Cambium is alayer of actively dividing cells found between the xylem and phloem tissues that is

responsible for the secondary growth of stems and roots.

What is Callus?

The undifferentiated mass of cells formed during tissue culture which can be further grown into new plants is called callus.

What is sclereids?

Sclereids or stone cells are the dead cells having extremely thick wall which are spherical or oval shaped. They are generally found in hard parts of plant body.

Name thin walled cells with chloroplast.

Parenchyma :)

What are the roles of meristem?

Meristem or meristematic tissues are tissues capable of cell division which are found in all the regions of the plants where growth takes place such as in apex, near internodes and also at the sides (in the lateral position of the plant body).

Therefore, their roles include to aid the primary and secondary growth of the plant body.

Differentiate between spongy and palisade parenchyma.

Palisade Parenchyma	Spongy Parenchyma
Their cells are columnar with intercellular spaces.	Their cells are oval or round in shape with air cavities.
They're found below the upper epidermis.	They're found below the palisade Parenchyma.
They're dark green in colour.	They're light green in colour.
They contain a high number of chloroplasts.	They contain comparatively lower number of chloroplasts.

How is annual ring formed ?

The plant that is present having various climatic condition shows different mode of activities cambium ring. If the season is spring the activity of cambium ring is more forming spring wood or early wood. And, if the climatic condition is not good i.e winter or autumn, the activity of cambium ring is less and form late wood. Because of which there forms different distinct ring with the addition of spring wood and autumn wood that is called annual ring. Each and every year one annual ring is...

Define mutation. Explain few significances of mutation.

The sudden, drastic, continuous and heritable change occured in an organism due to permanent change in gene is called mutation.

Some of the major significances of mutation are as follows:-

1. It helps in evolution because it incresess genetic variations and potential for individuals.

2. It helps the organisms to adjust itself against the environmental stresses.

3. The variations induced by mutation helps in natural selection.

4. It also helps in the evolution process of living beings

5. It...

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