CBSE Class 9 Science Practical Skills – Features of Monocot and Dicot Plants
To study the external features of root, stem, leaf and flowers of monocot and dicot plants.
A pea plant and an onion plant with root, stem, leaf and flowers, two paper sheets, simple dissecting microscope, a hand lens, slide, cover slip, razor blade, a few seeds of gram, pea, maize, petri dish and water.
Characteristics of monocots are as follows:
- These plants have single cotyledon in their seeds.
- Their leaves are narrower and have parallel venation.
- They have fibrous roots.
- They have trimerous flowers. Trimerous flowers bear different structures in 3’s or in multiples of 3.
Characteristics of dicots are as follows:
- These plants have two cotyledons in their seeds.
- Their leaves are broad and have reticulate venation.
- They have tap roots.
- They have pentamerous flowers. Pentamerous flowers bear different structures in 5’s or in multiples of
1. Wash the roots of both the plants and spread them on a newspaper.
2. Carefully observe the nature of roots of both plants.
3. Take one leaf of each plant and carefully observe their shape.
4. With the help of a hand lens observe the pattern of veins.
5. Take one flower of each plant.
6. Count the number of sepals, petals and stamens in each.
7. Now, carefully remove the carpel from each flower and cut its transverse section with a sharp razor blade.
8. Put a drop of water in the centre of a slide and with the help of brush transfer the section of ovary on the slide.
9. Cover the slide with a cover slip.
10. Observe this slide under the dissecting microscope.
11. Count the number of carpels in each ovary.
12. Soak both types of seeds in water in separate petri dishes overnight.
13. Remove the seed coat, try to split the seed and count the number of cotyledons in each.
Pea root: The root system consists of one main root called primary root. From the primary root several lateral roots arise.
Onion root: All the roots are similar and originating from the base of the stem.
Pea leaf: The leaves are broad. A thick vein called mid vein is present in the middle of the leaf. From this thick vein many veins are emerging which form a net-like design on both sides of midrib.
Onion leaf: The leaves are narrow. All the veins are parallel to one another and almost similar in thickness.
Pea flower: Flower bears five seals, petals and ten stamens. Pistil consists of style, stigma and ovary. Ovary consists of one carpel.
Some bead like structures called ovules are attached to the wall of ovary.
Onion flower: Flower bears six tepals and six stamens. Pistil consists of style, stigma and ovary. Ovary consists of three carpels. Some bead like ovules are attached to the ovary wall in each carpel.
Gram and pea seeds: Each seed of gram and pea has two cotyledons.
Maize seeds: Each seed of maize consists of only one cotyledon.
- The study reveals that dicot plants have tap root system, broad leaves with reticulate venation, five or in multiple of five sepals, petals and stamens in their flowers whereas monocots have fibrous root, narrow leaves with parallel venation, three or in multiple of three sepals, petals and stamens in their flowers.
- The dicot seeds such as gram, pea have two cotyledons while monocot seeds such as maize, wheat, onion have only one cotyledon.
- We should handle the blade carefully.
- The transverse section of ovary should be kept dipped in water otherwise it may dry.
Which plants have you taken for the experiment?
Pea and onion
Are both these plants angiosperms?
Because they both bear flowers and their seeds are enclosed in fruit.
Which root system is present in pea plant?
Tap root system
What are the identification features of tap root system?
In tap root system, one main root is present. From this secondary roots, and from secondary roots tertiary roots arise. In other words, we can say in tap root system, roots are differentiated into primary, secondary and tertiary roots.
Can you categorise the plants into monocot and dicot by looking their leaves?
Yes, dicot plants have reticulate venation while monocot plants have parallel venation.
What is venation?
Arrangement of veins in a leaf is called venation.
Name two plants in which venation is parallel and two plants in which venation is reticulate.
Parallel venation — Wheat and rice.
Reticulate venation – China rose and mustard.
What are pentamerous flowers?
Flowers having parts in multiples of five (five, ten, etc.) are called pentamerous flowers.
In which type of plants pentamerous flowers are present?
What is seed made up of?
Seed is made up of seed coat and embryo.
How can we identify whether a seed belong to a monocot or dicot plant?
By counting the number of cotyledons present in seed we can identify whether a seed belongs to a monocot plant or dicot plant.
How many cotyledons are present in a dicot seed?
What is the role of cotyledon in the seed?
The cotyledons are the “seed leaves” produced by the embryo. They serve to absorb nutrients packaged in the seed, until the seedling is able to produce its first true leaves and begin photosynthesis
NCERT LAB MANUAL QUESTIONS
How do we differentiate between fibrous root system and tap root system?
In the fibrous root system, roots originate from the base of the stem and all the roots are alike whereas in tap root system, roots are differentiated into primary, secondary, tertiary roots.
A plant have leaves with reticulate venation and floral parts consisting of 5 sepals, 5 petals, 5 stamens, and 5 carpels. In which group of angiosperms would you place this plant? Give reasons.
Leaves with reticulate venation, and pentamerous flowers are characteristic of dicot plants. So, the plant mentioned in the question is a dicot.
In a plant, name two features which you would examine to categorise it into a monocot or dicot plant.
Two features that we can examine to categorise a plant into monocot and dicot are
- number of cotyledons in a seed, and
- leaf venation.
Do all the flower have all the floral parts? Explore.
A typical flower has sepals, petals, stamens and carpels, such type of flowers are called complete flower. e.g., mustard, china rose, pea, etc. But some flowers may lacking any one or more than one part that are found in the complete flower. Such flowers are called incomplete flower e.g., sunflower, rice, wheat, etc.
Multiple Choice Questions/VSA
Which of the following is the characteristic of angiosperms?
(a) Presence of flower
(b) Presence of seeds enclosed in fruit
(c) Both (a) and (b)
(d) None of these
Fibrous root originates from
(b) base of stem
(d) any part of plant
Inside the ovary tiny dot-like structures present are
The individual unit of an androecium is
The four whorls of a flower starting from outside are
(a) corolla, calyx, androecium, gynoecium
(b) gynoecium, corolla, calyx, androecium
(c) corolla, androecium, gynoecium, calyx
(d) calyx, corolla, androecium, gynoecium
Plant is a dicot if
(a) leaves have reticulate venation
(b) leaves have parallel venation
(c) root system is fibrous
(d) flower is trimerous
The following pair has dicot seeds.
(a) Pea and onion
(b) Pea and gram
(c) Maize and pea
(d) Onion and maize
(a) male reproductive system
(b) female reproductive system
(d) root system
Which of the following is not a component of carpel?
Tepals are the individual units of
The terminal part of the carpel which receives pollen grains is called
In the following figure, X is
Select the odd one out.
In the diagram given below, what is X?
Which type of root is found in a pea plant? How this root is different from the root of onion?
(a) 5 sepals + 3 petals + 5 stamens
(b) 3 sepals + 5 petals + 3 stamens
(c) 3 sepals + 3 petals + 5 stamens
(d) 3 sepals + 3 petals + 9 stamens