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A PROJECT REPORT ON FLOWERS, ITS PARTS AND THEIR FUNCTIONS

Flowering occurs in plants with particular climatic changes such as sunny, cold and dry or drought conditions. In conducive growing conditions plant size and foliage increase, but many flowers are not produced.

Flowers are the reproductive organs of a plant. Sexual reproduction in plants is enabled by flowering and is a sign of plant survival. Some plants do not require reproduction by flowering but reproduce by sending out runners e.g., strawberry, and form identical plants. This form of propagation is termed asexual reproduction.

A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Magnoliophyta, also called angiosperms). The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs. Flowers may facilitate fusion of sperm and eggs from different individuals in a population or fusion of sperm and egg from the same flower. Some flowers produce diaspores without fertilization. Flowers contain sporangia and are the site where gametophytes develop. Flowers give rise to fruit and seeds. Many flowers have evolved to be attractive to animals, so as to cause them to be vectors for the transfer of pollen.

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The flowers are borne in the floral axis of the stem. Flowers are generally borne laterally on the floral axis. The flower is raised above the stem by a stalk called pedicel. The flower with a stalk is called pedicellate flower, e.g. hibiscus. If the pedicle is absent, the flower is called sessile, e.g. sunflower. The flattened tip is called thalamus or receptacle.

Flower is a modified dwarf shoot of the angiosperm. It develops either in the axis of the leaf bracts or at the tip of the axis. The terminal part of the pedicel is called thalamus.

A typical flower bears four floral parts. They are sepals, petals, stamens and pistil. These parts are borne on the receptacle.

Structure and function of flowersThe male gametes in flowers are the pollen, while ovules are the female

gametes. Pollen from one plant fertilizes the ovules of another plant through flowers, in the cross-fertilization method of reproduction.

A flower's male parts are the Stamens and female parts are the carpel. Though, most plants produce flowers that have both male and female reproductive parts, separate male and female flowers bloom in some plants.

Study the parts of a simple flower with reference to the location and function of the parts given in the following details.

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SepalsSepal, a modified leaf part, is found at the outermost region of the four

groups of flower parts. The sepals of a flower are collectively called the calyx and act as a protective covering of the inner flower parts in the bud. Sepals are usually green, but in some flowers (e.g., the lily and the orchid) they are the same color as the petals and may be confused with them. In some groups of plants (e.g., the marsh marigold and the anemone) they are absent. The small green leaf like structures at the base of the flower head in the aster family are not true sepals but bracts; the sepals are modified into a circle of tiny white hairs on the ovary. The sepals are sometimes fused into a tube around the base of the petals, as in the mint family. In some flowers, the sepals are free from each other while in some other they are joined together.

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http://www.answers.com/topic/flower


PetalsMostly colored to attract pollinating insects and are framed by sepals. Petal

is one of the four basic parts of a flower, next innermost organ from the sepal. The whorl of petals is known collectively as the corolla. The number of petals is usually constant within groups (e.g., five in the rose family), as are the numbers of the other organs. Identification by number is, however, complicated by various factors; the petals may be fused, inconspicuous, or entirely absent, in which case their role as the showy part of the flower is sometimes supplanted by modified leaves, the bracts, as in the dogwood and poinsettia, or by modified stamens, as in the lady's-slipper. Selective breeding can produce petal like stamens (e.g., in cultivated roses and geraniums) and so-called double flowers, i.e., varieties with

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more than the normal number of petals. Petals are usually brightly colored and often secrete perfume and nectar that attract insects and birds needed for cross-pollination. When fertilization has taken place the petals usually drop off; however, in some flowers they persist (see everlasting). In general there are fewer petals and their fusion is greater as the evolutionary development increases. Radial symmetrical arrangement also gives way to bilateral symmetry or even asymmetry. In some flowers, the petals are joined while in other flowers they are free from each other.

StamensStamen is one of the four basic parts of a flower. The stamen

(microsporophyll) is often called the flower's male reproductive organ. It is typically located between the central pistil and the surrounding petals. The group of stamens collectively called androecium. A stamen consists of a slender stalk (the filament) tipped by the anther in which microspores develop as pollen grains. The number of stamens is a factor in classifying plant families, e.g., there are 5 (or multiples of 5) in the rose family and 10 in the pulse family. In most flowers the stamens are constructed so as to promote cross-pollination and to avoid self-pollination; e.g., they may be longer than the pistil or may be so placed in relation to the pistil (as in the mountain laurel and the lady's-slipper) as to prevent the pollinating insect from transferring the pollen of a flower to its own pistil. There

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http://www.answers.com/topic/pollen


http://www.answers.com/topic/everlasting


may be differing maturation times for the stigma of the pistil and for the anther. In some plants there are some flowers (staminate) that bear stamens and no pistil and others (pistillate) that have a pistil and no stamens; these flowers may be borne on the same or on separate plants of the same species. In some highly developed flowers, especially double ones, and in some horticultural varieties (e.g., the geranium) the stamen may be modified into a sterile petal like organ.

PistilsPistil is one of the four basic parts of a flower, the central structure around

which are arranged the stamens, the petals, and the sepals. It is collectively called gynoecium. The pistil is usually called the female reproductive organ of a flowering plant, although the actual reproductive structures are microscopic. The pistil has a swollen or cylindrical base, the ovary containing the ovules, which develop into seeds after fertilization of egg cell(s) in the ovule. A pistil is composed of one or more highly modified leaves (carpel), each containing one or more ovules. A flower may have one or more simple pistils, each a separate organ, or, in higher orders, a compound pistil, formed of several fused carpel. Usually, there is above the ovary a stalk (the style) bearing on its tip the stigma, where the pollen grains land and germinate. The stigma is often sticky or hairy, to retain the

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pollen. Evolutionary relationships can often be inferred from the location of the ovary in relation to the other parts of the flower. If the stamens, petals, and sepals are attached beneath the ovary, the flower is hypogenous and the ovary is superior; if they are attached above, the ovary is inferior and the flower epigenous; if the ovary is located in a receptacle at the outer edges of which are attached the other flower parts, it is called superior or half-inferior and the flower perigynous. A flower that has one or more pistils but no stamens (or nonfunctional ones) is called pistillate, or female, as distinguished from a staminate, or male, flower, in which the pistil is nonfunctional or absent. The wall of the ovary protects the developing seeds. When the seeds are mature they are often found in some sort of seed case, a pod, perhaps, or a fruit or berry. Animals and birds that eat the fruit scatter the seeds abroad.

For the successful completion of my project, I carried out some research in different sources. It is said that "Man's greatest treasure tool is information." So, I

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went through various sources for collection of information that were necessary for my project. I did the methodology process in two methods:

i. Primary Source: I asked with the elderly people about the flowers like my father, brother and aunt. They gave me a lot of information about the flowers and its parts.

ii. Secondary Source: But the information provided by my family members only was not sufficient for the completion of my project. So, to gain further information I carry out the secondary source of data collection. First of all, I went to libraries, different websites and listened and watched various television shows relates to the flowers and their parts. I went through the collection dictionaries, encyclopedia and different books which contained the knowledge about the flowers.

During the project, I found and learned many things. I found out that flower is the very important part of the plant. If there are no flowers in a plant then the plant cannot reproduce sexually. Flowers are also attractive part of the plant which

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attracts many people and animals. Flowers have mainly four parts. They are sepals, petals, stamens and pistil. Each of them has their own functions too. The sepal is the outermost whorl of the flower which encloses and protects the inner parts of the flower. The petal is the second whorl of the flower and it secrets nectar and has attractive colour which attracts the insects. This helps in pollination. Stamens are the third whorl of the flower which produces the male gametes, the pollen grains, required for the sexual reproduction of the plant. Pistil is centrally placed part of the flower. It represents the female reproductive organ of the flower. Ovule, one of its parts, develops the female gametes required for sexual reproduction. Another part of the pistil is stigma which catches the pollen grains during pollination while ovary later on changes into fruit.

After doing this project report on Flowers, Its Parts and Their Functions I came to the conclusion that flower is a important part of the plant. Without flower

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the reproduction of the plant would have been almost impossible. The flowers reproduce by three steps. In the first step the stamens produce male gamete and pistil produce female gamete, ovule. Then in the second step the male gamete, pollen grain, is transferred from anther to stigma of same or different plants by means of wind, insects, man, etc. Then in the third stage fertilization occurs in ovary and the zygote is formed which is later developed into a new plant. A plants without flowers can never produce seeds and fruits. So, from this we can conclude that flowers and its parts have a great role to play in the life of plants.

I recommend the following after the completion of my project:

i. Flower is one of the important parts of plant.

ii. We should not plug the flowers when not necessary because it may hamper the life cycle of the plant.

Throughout this project, I went through various websites, libraries and books. I also chatted with some of my friends about the flowers and I also consulted with my teacher who used to teach me science in my previous school.

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These acts helped me a lot in providing me all the necessary information required for the successful completion of this project. Some of my references are mentioned below:

www.google.com.np

www.wikipedia.org

www.answers.com

www.ask.com

Science Book (Grade-6)

Biology Book (Bridge Course)

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