These DAV Class 5 Science Notes and DAV Class 5 Science Chapter 2 Notes – Plants act as excellent revision resources, particularly in preparation for board exams.
Plants Class 5 DAV Notes
Photosynthesis:
→ A plant makes its food in green leaves. Thus, green leaf is called the food factory of plants. The process by which green plants make their food is called photosynthesis.
→ Raw Materials for Photosynthesis: Carbon dioxide and water are the raw materials for photosynthesis. Plant takes water from soil through roots. Plant takes carbon dioxide from air through stomata.
→ Stomata: There are minute pores on the surface of leaves. These pores are called stomata.
→ Chlorophyll: The colour of leaves are green because of a pigment called chlorophyll. Chlorophyll traps solar energy from sunlight.
→ Insectivorous Plants: Some plants grow in soil which is deficient in nitrogen salts. Such plants fulfill their need of nitrogen by feeding on insects. These plants are called insectivorous plants. Examples of insectivorous plants are Venus fly trap, pitcher plant and bladderwort.
Reproduction In Plants:
→ The process by which a living being produces its own kind is called repro-duction. Plants reproduce in two ways:
(a) Reproduction through seeds
(b) Reproduction through different parts; like underground stem, stem cutting, root and leaf.
Reproduction Through Seeds:
→ Seeds usually develop inside fruits. When the fruit ripens, seeds become mature. Mature seeds get dispersed through various agents; like air, water, insects and human beings.
→ Dispersal of seeds: Spreading of seeds far and wide is called dispersal of seeds.
Structure Of Seed
A seed has following structures: Seed coat
→ Germination of Seed: When a seed gets favourable condition; like proper temperature, moisture and air; it grows into a new plant. This process is called germination of seed. Cotyledons provide food for the growing plant. When new leaves emerge, the plant starts making its own food.
Reproduction By Different Parts Of The Plant
→ Vegetative Reproduction: When reproduction takes place through under-ground stem, stem cutting, root or leaf; this is called vegetative reproduction.
(a) Reproduction through under-ground stem: In some plants, a part of the stem is present underground. This part of the stem develops roots and shoots to make new plant. Examples: banana, ginger and potato.
(b) Reproduction by stem cutting: In some plants, stem cutting of the plant develops into a new plant. Examples: sugarcane, rose, bougainvillea and grapes.
(c) Reproduction through root: In some plants, the fleshy roots give rise to new plants. Examples: dahlia, asparagus and sweet potato.
(d) Reproduction through leaf: In some plants, young plants come out from the notches on the leaf margin. Example: Bryophyllum.
Agents Of Seed Dispersal
→ Dispersal by Humans: Humans select seeds of useful plants and sow them in the soil. Thus, farmers are important agents of seed dispersal.
→ Dispersal by Wind: Seeds of some plants have lightweight and feathery structures. Such structures help the seeds to float on air. Thus, the seeds are carried away far and wide by wind. Examples: madar, thistle and dandelion.
→ Dispersal by Water: Some plants grow in water or near water. Seeds of such plants can easily float on water and thus get dispersed. Examples: coconut, water lily, hydrilla and lotus.
→ Dispersal by birds, insects and rodents: Sparrows, ants, rats, squirrels, etc. carry fruits and grains to their burrows, nests and other places. Some fruits and grains are dropped on the way. These seeds germinate to produce new plants.
→ Dispersal by Animals: Some seeds live hook like structures. Thus, such seeds stick to the fur of animals and get carried away. Examples: castor, burdock, cockleburr and mimosa. In some other cases, the seeds are dispersed through animal droppings, e.g. papaya, melon, pumpkin, gourd and mango.
→ Dispersal by Cracking and Bursting: Some fruits burst open when they become mature. This helps in seeds getting spread to a wider area. Examples: pea, ladyfinger, bean and balsam.
→ Chlorophyll: The green pigments present in leaves.
→ Cotyledons: Parts of a seed which contain food for the baby plant.
→ Germination: The process of development of seeds into new plants.
→ Photosynthesis: The process by which plants make their own food is called photosynthesis.
→ Seed Coat: The outer covering of seed is called seed coat.
→ Dispersal of Seeds: The process of [ scattering seeds far and wide is called dispersal of seeds.
→ Vegetative Reproduction: When a plant reproduces through stem, root and leaves; it is called vegetative reproduction.