Plant Life – CBSE NCERT Science (Biology)
CATEGORIES OF PLANT
Small plants with tender green stem… they usually don’t have branches. E.g. coriander, mustard, wheat, paddy
Medium sized plants with thick brown woody stems..
branches arise from the base of the plant
Tall plants with a hard and thick brown stem.
Branches arise from the upper part of the stem.
E.g. Mango,Guava etc
Climb up with the support of neighboring structures… E.g: money plant, pea plant
Cannot stand upright and spread on the ground. E.g. water melon, pumpkin
PARTS OF A PLANT
It has a primary root (main) called the Tap root and from it a number of branches called lateral (secondary) roots arise..
E.g.: Mango, Guava Carrot
No main root. A number of similar sized roots arise in a cluster
below the stem and spread out in the soil.
FUNCTIONS OF A ROOT
Anchoring the plant to the ground.
Absorbing water and nutrients from the soil.
Holding the soil together.
Storing food which in turn is eaten by us….as in turnip radish etc.
Main axis of the shoot system which bears the branches, leaves, flowers buds, fruits and seeds.
Apical bud – present at the tip of the stem and which helps in the length wise growth.
Node – the place from where the leaves and the branches arise.
Internode – the portion of the stem between two nodes.
Axillary buds – these buds give rise to branches.
FUNCTIONS OF A STEM
Keeps the plant upright.
Bears the leaves flowers and the fruit.
Transports water and minerals from the root to the leaves.
Transports the food manufactured by the leaf to the other parts of the plant.
When young green stem prepares food.
Stores food in some cases..like ginger, onion, potato.
PETIOLE: A small stalk by which a leaf is attached to the stem.
LAMINA: The broad flat and green extended part of a leaf..the edges of a lamina can be smooth as in mango or serated as in a rose.
MIDRIB AND VEINS: The stalk of the leaf continues into the lamina forming a midrib. The midrib branches out as veins which form a network in the leaf called Venation.
Reticulate Venation- Veins are arranged in a net like pattern. E.g. Peepal, Mango.
Parallel Venation- Veins run parallel to one another. E.g. Grass, Wheat.
FUNCTIONS OF A LEAF
Transpiration – Lose extra water by transpiration through small pores called stomata on the underside of the leaves.
Respiration – Exchange of gases (carbon dioxide and oxygen) during photosynthesis and respiration through stomata
Small green leaf like structures present at the base of the flower.
They protect the petals in the bud stage and provide support to the petals when the bud opens to form a flower.
Flat, broad, generally colored.
May be in one or more layers.
May be joined or separate.
They attract flies and insects.
Male reproductive organs consists of two parts:
Filament—A long thin tube like structure
Anther—A knob like structure attached to the top of the filament. The Anther produces pollens (male gamete)
Female reproductive organ consists of three parts:
Stigma—The top portion which receives the pollen.
Style— It’s a tube like structure joining the stigma to the ovary.
Ovary— Contains beads like structure called ovules.
The OVARY turns into a fruit and the ovules turn into a SEED.
FUNCTIONS OF A FLOWER
SOURCE OF FOOD