Grade 5, Science Olympiad (CBSE) - Reproduction in plants
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Grade 5 | Science | Reproduction in plants, Living, non living things and Plants, Olympiad, CBSE, ICSE, Maths Olympiad, Science Olympiad, English Olympiad
Reproduction in plants
Plants can reproduce new plants (offsprings) by two ways:
- Sexual reproduction - Requires male and female gametes
- Asexual reproduction - A part of the plant is used to reproduce an identical plant
*Gametes: They are the male and female reproductive cells - pollen and eggs.
Sexual reproduction in plants:
In sexual reproduction male (pollen) and female (ovules) gametes diffuse to produce a new plant. New plant produced is not completely identical to any one of the parent. Flowers are the main sex organs of plants. They consist of both male and female parts.
Stamen is the male part which consists of anther and filament. It produces pollen grains. Pollens dust, generally yellow colored, is transferred to female parts by different agents called pollinators.
A pistil is the female reproductive part. It contains single or multiple carpels. A carpel consists of stigma, style and ovary. An ovary is the swollen base of pistil and it contains ovules(eggs). These ovules are the potential seeds. Stigma is the sticky part to which pollen grains are attached.
Pollens from anthers are transferred by wind, water, insects or animals. These pollens when fall on stigma become attached. The process of transfer of pollen grains from male reproductive parts (stamens) to female reproductive parts (pistil) is called Pollination.
These pollen grains then move to the base of the pistil and into the ovary where they diffuse with ovules to form zygotes which finally turn into produce seeds. This process of combination of pollen and ovule to form a zygote is called fertilization.
Imp concepts:
Self-pollination - When pollens from the same flower fertilize the ovules of the same flower.
Cross-pollination - When pollens from a flower fertilize the ovules of a different flower.
Abiotic pollination - Pollination occurred with the help of non-living things like wind and water is known as abiotic pollination.
Biotic pollination - Pollination occurred with the help of living things like insects, birds, animals and humans is known as biotic pollination.
Ferns and mosses reproduce through spores.
Seeds Dispersal: Seeds produced are fertilization contain plant offspring. These seeds are disbursed by various methods.
- Heavy and fleshy fruits like apples and coconut fall on land due to gravity. Fleshy fruit's seeds are dispersed to small distances.
- Dandelion or other winged seeds are taken to far off places by the wind.
- Seeds of water lily or palm are dispersed by water. They are also dispersed to very far off places.
- Seeds of peas are spread by an explosion. They are dispersed over a small distance.
- Cocklebur fruit has hooks like a structures which help it to get attached to the fur of animals and get dispersed to far off places.
- Some fruits are dispersed by animals are carried over to slighly longer distances.
- Wind carries some seeds to still further distance.
- Water carries seeds to the farthest distance.
- Maple and Dandelion are dispersed by wind.
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