The Flower

Todays topic is The Flower for ICSC biology class 6.A plant consists of many parts such as stem, leaves, buds, flowers and fruits. Flowers are generally colourful and attractive so they attract everyone and make the plant beautiful.

The Flower

Which are the main parts of a flower?

The various parts of the flower are -

1.Pedicel - The stalk of the plant is known as pedicel.Plants like lily and tulip consist of a single pedicel with one flower. Plants such as lilac consist of branched pedicel with many flowers. Some plants lack pedicel. These are known as sessile flowers. For example - saffron. It helps in holding the flower in a suitable position in order to expose them properly to the sun and attract insects for pollination.

2.Thalamus - It is a small, swollen part present on the top of the stem below the flower. It protects the inner, delicate parts of the plant.

3.Calyx - It is the first whorl of the flower and is also known as sepal. It is green in colour and is capable of performing photosynthesis. It gives protection to the flower in its bud stage.

4.Corolla - They form the second whorl of the flower.They are also known as petals. They are mostly bright in colour and are scented which make them beautiful and attractive. Thus they help in pollination by attracting insects, bees and butterflies. The reproductive parts of the flower are surrounded and protected by corolla.

5.Androcium - It is the third whorl of the flower and is also known as the stamen. It is the male reproductive of the flower. It further consists of two parts. These are -

(a) Anther - It is the upper swollen part and consists of pollen grains.

(b) Filament - It is the long stalk that holds the androcium upright.

6.Gynoecium - It is the fourth and the innermost whorl of the flower. It is also known as pistil or carpel. It is the female reproductive part of the flower. It consists of three parts. These are -

(a) Stigma - The part of the carpel or pistil where the pollen grains are landed is known as the stigma.

(b) Style - Stigma is supported by a long stalk known as the style. It connects the stigma and the ovary.

(c) Ovary - It is found at the base of the pistil or carpel and looks swollen. It consists of ovules which are round in shape.

The female part of the flower helps in the process of reproduction by producing eggs.

What are complete and incomplete flowers?

(a)Complete Flowers - The flowers that consist of all the four whorls are known as complete flowers. For example - hibiscus or china rose, pea etc.

(b)Incomplete Flowers - The flowers in which one or more whorls are missing are known as incomplete flowers. For example - mulberry, papaya etc.

What are unisexual and bisexual flowers?

(a)Unisexual Flowers - Flowers that consist of only one reproductive part either male (androcium or stamen) or female (gynoecium or carpel) are known as unisexual flowers. For example - papaya etc.

(b)Bisexual Flowers - The flowers that consist of both male and female reproductive parts are known as bisexual flowers. For example - rose, hibiscus etc.

What are the functions of flowers?

The two main functions of flowers are reproduction and production of fruits and seeds. The process of reproduction consist of two steps i.e pollination and fertilization.

What is pollination?

The process of pollination involves the transfer of pollen grains from the anther to the stigma of the same or another flower.

What are the types of pollination?

Pollination is of two types -

*Self Pollination - When the pollen grains are transferred to the stigma of the same flower or the flower present on the same plant, this type of pollination is known as self pollination.

*Cross Pollination - When the pollen grains are transferred from the anther ro the stigma of the flower that is present on some other plant, but the same type of plant, this type of pollination is known as cross pollination.

Which are the agents of pollination?

The agents that help in the transfer of pollen grains from the anther of one flower to the stigma of another flower are known as the agents of pollination. For example - wind, water, insects, birds and animals.

(a)Pollination by wind - The pollination carried out by wind is known as anemophily. For example - rice, maize, oats, grass etc.

What are the characteristics of plants that are pollinated by wind?

1.Pollen grains should be light and drydry so that they can be easily blown away by wind.

2.These plants have to produce pollen grains in large quantities to avoid their wastage.

3.To catch the pollen grains easily, the stigma of the flower should be feathery.

4.These plants are generally colourless, odourless (don't have any smell) and small in size.

5.Nectar is not produced in these flowers.

(b) Pollination by water- When pollination is carried out by water, it is known as hydrophilly. For example - hydrilla,vallisneria etc. In this type of pollination the male flower on getting matured and detaching from the plant starts floating on the surface of water. water.When its pollen grains come in contact with the stigma of the female flower floating on the surface of water, pollination occurs.

(c) Pollination by insects - When pollination is carried out by insects, it is known as entomophily. For example - marigold, rose, orchids etc. Some of the insect pollinators are flies, butterflies, wasps, bees etc.

What are the characteristics of flowers pollinated by insects?

1.These flowers are generally large in size and have bright colours.

2.They produce a sweet juice called nectar and are scented.

3.They produce pollen grains in small amount.

4.Both the stigma and pollen grains are sticky.

(d) Pollination by animals - The animals that carry on pollination are birds,squirrels, bats etc. Pollination occurs when pollen grains sticked to the body of these animals drop on the stigma of another flower.

To check the next part of the chapter click on this link : https://lessonstobelearneda-z.blogspot.com/2022/03/fertilization-in-plants.html

Hope you liked the topic The Flower for ICSC biology class 6.You can practice this topic using Worksheets for Science. Please share it and comment if you want Worksheets of Science on any other topic.

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