Sexual Repooduction
Write the differences in structure
of male and female flowers.
Answers
Answer:
The female organ of a flower is called carpel. It helps in making female gametes or egg cells of the plant and is present in ovules. The malegametes fertilise the female gametes. The fertilised egg cells grow in ovules and become seeds.
Explanation:
Sexual Reproduction in Flowering Plants
Sexual reproduction is the production of a new organism from two parents by making use of their gametes or sex cells. Plants also have male and female sex organs. When the male gamete combines with the female gamete, a new seed is formed. This seed when provided with suitable environment is germinated and a new plant is grown.
SHIKHA GOYAL
MAR 11, 2016 16:15 IST
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Sexual reproduction is the production of a new organism from two parents by making use of their gametes or sex cells. Plants also have male and female sex organs. These sex organs in plants are carried within the flower and the seeds which are inside a fruit. Such plants are called angiosperms or flowering plants as they reproduce by sexual reproduction method.
Jagranjosh
Parts of a Flower
Steps for sexual reproduction in plants
The male organ of a flower is called stamen. It helps in making male gametes of the plant and is present in pollen grains.
The female organ of a flower is called carpel. It helps in making female gametes or egg cells of the plant and is present in ovules.
The male gametes fertilise the female gametes.
The fertilised egg cells grow in ovules and become seeds.
When germinated, these seeds become new plants.
Various Parts of a Flower
Receptacle: It is a base of a flower above the flower stem. It is at receptacle that all other parts of a flower are attached.
Sepals: These are the green leaf-like parts which are present on the outer most part of the flower. Sepals help in protecting the flower when it is in the form of a bud. All sepals of a flower together are called calyx.
Petals: Petals are the colourful leaves of a flower. All the leaves of a flower together are called corolla. The petals of a flower have fragrance and they attract insects for pollination. Their function is to protect the reproductive organs present in the centre of a flower.
Stamen: Stamens are the male reproductive organ of a plant. They are present inside the ring of petals and are little stalk with swollen tops. Stamen is made of two parts, anther and filament. The stalk of stamen is called filament and swollen top is called an anther. The anther of a stamen produced pollen grains and stores them. These pollen grains contain male gametes of the plant. A flower has a lot of stamens in it.
Jagranjosh
Carpel: Female reproductive organ of a Plant. Carpel is also known as Pistil.
Pollination
Fertilisation
Pollination
When pollen grains from the anther are transferred to the stigma of a carpel, it is called pollination. This is important because it is due to pollination that male gametes are able to combine with female gametes. Pollination is done by insects like bees, butterflies and birds, wind and water.
There are two types of pollination, self-pollination and cross-pollination. When pollen grains from one flower carried to the stigma of the same flower or to another flower of the same plant, it is called self-pollination. And when pollen grains from a flower of one plant are carried to the stigma of a flower of another similar plant, it is called cross-pollination.
Jagranjosh
Pollination
Insects help in pollination. This happens when an insect sits on a flower of one plant to suck nectar then the pollen grains from anther stick to its body. Now, when this insect flies and sits on the flower of another similar plant then the pollen grains are transferred and they stick to the stigma of the flower of another plant. This way insects help cause cross-pollination. Wind too helps in cross-pollination.
Fertilisation
After pollination, next step is fertilisation. In this step, male gametes present in pollen grains joins with the female gametes present in ovule.
When the pollen grain falls on stigma it bursts open and a pollen tube grown which moves through the style towards the ovary and enters ovule. Male gamete moves down through the pollen tube. The tip of pollen tube bursts open in the ovule and the male gamete come out. In the ovule, male gamete combines with the nucleus of female gamete and fertilised egg is formed. This fertilised egg is called zygote.