1. Plants -
ü The plants are biotic (living) components present around us.
ü The plants grow with time. They also reproduce their own kind.
ü They consume food and excrete out waste.
2. Grouping Of Plants - (Based on size)
ü Plants are usually grouped as herbs, shrubs, trees, creepers and climbers based on their height, stems and branches.
ü Herbs- Have soft, green and week stems. Example: wheat, rice, maize, mint, sunflower etc.
ü Shrubs: They are bushy and have hard stems that do not bend easily. These are plants with the stem branching out near the base. Example: china rose, lemon, jasmine etc.
ü Trees: These are big plants which have a tall and strong stem (trunk). Stems have branches in the upper part, much above the ground. Live for many years. Example: neem, banyan, coconut, mango etc.
ü Climbers: Have weak stems and cannot stand erect. They take support of other trees and climb on them. Example: pea, grape etc.
ü Creepers: Plants which creep on the ground and spread out. Example: pumpkin and watermelon.
3. Grouping Of Plants - (Based on Life cycle)
ü Annuals: Plants whose life cycle is completed in the one season. These are generally herbs. Example: wheat and mustard.
ü Biennials: Plants whose life cycle requires two seasons for completion. They are generally herbs and rarely shrubs. Example: carrot, radish and potato.
ü Perennials: Plants whose life cycle runs for more than two seasons example: guava, babul and palm trees.
4. Root System
ü It is the underground portion of the plant.
Tap Root: It is the main primary root arises from lower end of the stem. A number of tiny branches called secondary roots. Example: mustard, neem, rose etc. Fibrous Root: A bunch of roots arises from the base of stem. Example: wheat,maize, etc.
ü Functions of root -
(i) Roots absorb water and nutrients from the soil.
(ii) Roots help the plant to stand erect.
(iii) Roots check soil erosion.
(iv) Roots store food.
(v) Prop roots offer extra support.
5. Shoot System -
ü The part of the plant which grows above the soil. It includes stems, branches, leaves, flowers and fruits.
ü Stem - Gives rise to a number of branches that bear leaves. The stem bears leaves, flowers and fruits.
ü Function of Stem -
(i) It provides support to plant.
(ii) It bears important plant parts.
(iii) It helps in transportation of water and food.
(iv) Underground stems store food.
(v) Thick and fleshy stems make food.
(vi) Stem modified into tendrils give extra support for plants.
6. Leaf -
ü Leaf arises from the leaf base. A leaf usually has a petiole and a lamina.
ü Parts of leaf -
Petiole: Stalk of the leaf with which it joined to the stem.
Leaf lamina: The flat green portion of the leaf.
Veins: These are the network of small, narrow, tube-like structures on both sides of the midrib present in the middle of leaf.
ü The design made by veins in a leaf is called the leaf venation.
ü If this design is net-like on both sides of midrib, the venation is reticulate.
ü In the leaves of grass you might have seen that the veins are parallel to one another. This is parallel venation.
ü Function of Leaf -
(i) Transpiration: Process of losing water by the leaves of a plant.
(ii) Preparation of food by the process of photosynthesis.
7. Flower -
ü It is the reproductive part of the plant.
ü Function of Flowers:
(i) Help in reproduction.
(ii) These become fruits that store food and seeds.
(iii) Modified flowers like cauliflower, broccoli are rich sources of vitamins.
ü Parts of Flower -
ü Pedicel: Stalk of the flower through which the flower is joined to the branch. It has joined to the branch.
ü Sepal: Small green leaf-like structures on the thalamus. They protect the flower.
ü Petals: Brightly colored leaf-like structures present inside the sepals. Petals attract the insects and help in the process of reproduction.
ü Stamens: These are long, thin and needle-like structures. These are male organs of the flower. It consists of two parts: Anther, Filament.
ü Anther: The swollen tip of each stamen that encloses in it a small powdery substance called pollen grains.
ü Filament: Long stalk-like structure that joins the anther with thalamus.
ü Carpel: It is a flask-shaped organ in the centre of flower. It is the female organ of the flower. It consist three parts: Style, Stigma and Ovary.
ü Style: Long thin tube-like structure which is swollen at the base.
ü Stigma: Small, round and sticky part of the carpel at the top of the style the
ü traps the pollen grains.
ü Ovary: Swollen part of carpel that contains ovules.
NCERT PRACTICE QUESTIONS
1. Correct the following statements and rewrite them in your notebook.
(a) Stem absorbs water and minerals from the soil.
(b) Leaves hold the plant upright.
(c) Roots conduct water to the leaves.
(d) The number of sepals and petals in a flower is always equal.
(e) If the sepals of a flower are joined together, its petals are also joined together,
(f) If the petals of a flower are joined together, then the pistil is joined to the petal.
Ans-
(a) Roots absorb water and minerals from the soil.
(b) Roots hold the plant upright.
(c) Stem conducts water to the leaves.
(d) The number of petals and sepals in a flower is usually equal.
(e) If the sepals of a flower are joined together, its petals are not necessarily joined together.
(f) If the petals of a flower are joined together, then the pistil is not necessarily joined to the petal.
2. Draw (a) a leaf, (b) a tap root and (c) a flower, you have studied for Table 7.3 of the textbook.
Ans:
3. Can you find a plant in your house or in your neighborhood which has a long but a weak stem? Write its name. In which category would you classify it?
Ans: Yes, we find a money plant in our house. It is a climber.
4. What is the function of a stem in a plant?
Ans- A stem performs following functions
(i) The stem and its branches hold leaves to get maximum sunlight.
(ii) It transports water from roots to different parts of the plant.
(iii) It transports food from leaves to different parts of the plant.
(iv) It bears leaves, flowers and fruits.
5. Which of the following leaves have reticulate venation?
Wheat, tulsi, maize, grass, coriander (dhania), china rose.
Ans: Tulsi, china rose.
6. If a plant has fibrous root, what type of venation are its leaves likely to have?
Ans: Parallel venation.
7. If a plant has leaves with reticulate venation, what kind of roots will it have?
Ans:Tap root.
8. Is it possible for you to recognize the leaves without seeing them? How?
Ans: We cannot exactly recognize the leaves without seeing them. We may be able to have some idea by touching and smelling them.
9. Write the names of the parts of a flower in sequence, from outside to inside.
Ans: The names of various parts of a flower from outside to inside are:
(i) Sepals
(ii) Petals
(iii) Stamens
(iv) Pistil
10. Which of the following plants have you seen? Of those that you have seen, which one have flowers?
Grass, maize, wheat, chilli, tomato, tulsi, pipal, shisham, banyan, mango, jamun, guava, pomegranate, papaya, banana, lemon, sugarcane, potato, groundnut
Ans:
11. Name the part of the plant which produces its food. Name this process.
Ans: Leaves produce food for the plant. This process is called photosynthesis.
12. In which part of a flower you are likely to find the ovary?
Ans: We find ovary in pistil. It is the lowermost part of the pistil.
13. Name two flowers, each with joined and separates sepals.
Ans:
Flowers with joined sepals:
(i) Datura
(ii) Loki
Flowers with separate sepals:
(i) Gurhal
(ii) Mustard
Junior Science Topic - Getting To Know Plants. Chapter notes, video lectures, power point presentation and NCERT exercise solution. (Class 6, CBSE syllabus, chapter 07)
By - EduPorm India - The Educational Platform
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