Revision Notes of Ch 7 Getting to know Plants Class 6th Science
- From where does a plant come?
- Classification of plants on the growth habit
- Classification on the basis of life cycle
- Parts of plants and their functions
From where does a plant come?
→ A plant comes from a seed.
→ This seed is covered with seed coats, which protect the seed.
→ This seed contain a baby plant inside, it has a tiny root towards the outer side.
→ The tiny root is termed as radicle.
→ It also has a tiny shoot towards the inner side.
→ The tiny shoot is termed as plumule.
Classification of plants on the growth habit
→ The plants are classified in five types based on growth habit:
(i) Herbs
(ii) Shrubs
(iii) Trees
(iv) Climbers
(v) Creepers
(i) Herbs
→ Have soft, green and weak stems. Usually its height is short and may not have many branches. It is used for food, flavouring, medicine or perfume.
→ Examples: rice, wheat, maize, sunflower, mint, etc.
(ii) Shrubs
→ They are bushy and have hard stems which do not bend easily. These plants have their stem branching out near the base.
→ Examples: lemon, China rose, jasmine, etc.
(iii) Trees
→ These are big plants which have strong and long stem. Live for many years.
Examples: mango, neem, banyan, coconut, etc.
(iv) Climbers
→ Plant that take support on neighbouring structures and climb up are called climbers. It has weak stems and cannot stand erect.
→ Examples: pea, grapes etc.
(v) Creepers
→ Plants which creep on the ground and spread out is called creepers. It has weak stems that cannot stand upright. Example: pumpkin and watermelon.
Classification of Plants on the basis of life cycle
→ The Plants are classified in three types on the basis of life cycle:
(i) Annuals
(ii) Biennials
(iii) Perennials
(i) Annuals: Plants whose life cycle is completed in one season. Examples: wheat and mustard.
(ii) Biennials: Plants whose life cycle requires two seasons for completion. Example: carrot, radish and potato.
(iii) Perennials: Plants whose life cycle runs for more than two seasons. Example: guava, babul and palm trees.
Parts of plants and their function
→ Plants are divided in 3 types based on their functions:
(i) Root System
(ii) Shoot System
(iii) Flowers
(i) Root system
→ The underground part of a plant is called root.
Types of root system:
(a) Tap root system
→ Primary root comes out from the seed after germination. It is also called true roots.
(b) Fibrous root system
→ These roots grow from the base of the stem have a bushy appearance. Fibrous roots are thin and almost equal in size.
Functions of roots
→ Help to anchor the plant firmly into the ground.
→ Root help plants to absorb water and nutrients from soil.
(ii) Shoot system
→ All parts of a plant that are above the ground form the shoot system.
Types of shoot system:
(a) Stem
→ It holds leaves in position and helps them to spread out as the stem and its branches grow.
→ It bears flowers, buds, leaves, and fruits.
(b) Leaf
→ A leaf is a flat and green structure on a plant, coming out from a node on the stem and always bearing a bud in its axil.
→ Parts of leaf are:
• Petiole
• Leaf lamina
• Veins
(iii) Flowers
→ A flower is the reproductive organ of a plant.
→ Flower gets developed into fruits and the fruits contain seeds with them for next generation.
Parts of flowers:
(i) Pedicle: Stalk of the flower through which the flower is joined to the branch.
(ii) Sepal: Small green leaf-like structure on the thalamus.
(iii) Petals: Petals attract the insects and help in the process of reproduction.
(iv) Stamens: These are male organs of the flower. It consists of two parts:
(a) Anther
(b)Filament
(v) Carpel: It is female organ of the flower. It consists of three parts:
(a) Style
(b) Stigma
(c) Ovary