the realtionship betwen flowers, fertilization....?

Question

can someone explain the relationship between flowers, fertilization, fruits, and seeds.

Answer 1

The flower is the sexual reproductive part of an angiosperm. It consists of four whorls of modified leaves : sepals, petals, stamens and carpals. The stamens are the male reproductive parts which includes the sporangia which produces pollen. The carpals are the female reproductive parts and includes the sporangia that produces the egg.

Pollen Development:
A pollen grain is an immature male gametophyte.
It is produced within the sporangium of the anthers.
The diploid microspore mother cell will undergo meiosis and form 4 haploid microspores.
The microspores nuclei will undergo mitosis and produce a tube nucleus and a generative nucleus.
A thick wall forms around the spore in a specific pattern, producing the pollen grain or immature male gametophyte.

Ovule Development:
The ovule is an immature seed. It is formed within the ovary and contains the female gametophyte.
The female gametophyte is the embryo sac and forms in the following way. The megaspore mother cell undergoes meiosis to form 4 haploid (N) megaspores.
One of the 4 will continue to develop, while the other 3 dissolve. The remaining megaspore grows and its nucleus will undergo 3 mitotic divisions, forming 1 large cell with 8 haploid nuclei. This will develop into the embryo sac. This sac contains a specific arrangement of these nuclei in the following order: The egg cell is located near the micropyle surrounded by 2 other cells called synergids. At the opposite end 3 antipodal cells are found. In the center of the sac will be found 2 polar nuclei.

Pollination is the placement of the pollen on the stigma of the carpal. This pollen transfer can be accomplished by wind, insects, built in mechanical discharge, and man. Once the pollen lands on the stigma, a series of chemical reactions takes place allowing the pollen grain to begin producing a structure called the pollen tube. As this is happening, the generative nucleus will divide and produce 2 sperm nuclei. This pollen grain with the pollen tube and 3 nuclei is considered the mature gametophyte. The pollen tube will work its way through the style of the carpal and touch the micropyle of the ovule. Here the sperm nuclei will enter the embryo sac and fertilize the egg and the two polar nuclei; hence the term double fertilization. The fertilized egg (2N) will develop into the immature seed plant, while the (3N) central cell will develop into the endosperm or food storage area of the seed.

The seed is protected by the seed coat or testa.
The micropyle is the only opening into the seed. It is through here that the water will enter to start germination.
The seed contains stored food in the form of seed leaves (cotyledons). Some seeds contain one (monocots) while other contain 2 (dicots).
The embryo plant contains several areas : the area above the attachment of the cotyledons is the epicotyl. This will develop into the shoots and leaves of the developing plant. The area below the attachment is called the hypocotyl. This will develop into the roots of the plant.

The fruit of a flower develops from the ovary. They protect the seeds and allow for their dispersal. Fruits may be classified in many ways.
Simple Fruits: These fruits develop from a single ovary. Peach, cherry, soybean.
Aggregate Fruits: These fruits develop from a single flower with many carpals. Strawberry.
Multiple Fruits: Fruit develops from a group of tightly clustered flowers. Pineapple.

Answer 2

Flowers contain the reproductive structures of angiosperms.

After pollen lands on the stigma of the flower and the pollen tube grows down to the ovule, two sperm nuclei enter each ovule. Then double fertilization occurs. One sperm nucleus joins with the egg nucleus and makes the zygote which will develop into the embryo. The other sperm nucleus joins with the two polar nuclei to make the endosperm nucleus which will produce the food storage tissue of the seed.

The ovule develops into the seed.
The ovary (bottom part of the pistil) develops into the fruit.

Answer 3

The flower attracts the insects which aid in fertilization. The flower is the part of the plant that develops the fruit. It may have male, female or both parts. Seeds develop in the fruit after fertilization. Fertilization takes place in the flower.

Answer 4

flowers are the "sex organs" of plants (angiosperms in particular).
As plants are physically separated by space (distance) from other plants they need help to get the pollen (plant sperm) to the female ovary and ovule. This is either done by wind blowing it onto the female parts in the flower or using insects or other animals to get the pollen onto the female parts of the flower.

Once the sperm gets onto the female parts ( and in this case its the stigma a pollen tube grows down to the ovule (as the pollen does not swim like sperm) and fertilises it there.

Once fertilisation has taken place the seed begins to develop. The seed is the equivalent of a baby plant. It carries a food store (cotyledons) to get it started before it has to grow properly. Its not beneficial to the seed to hang around the parent plant once its ready to "disperse", because the parent will take its sunlight, water, nutrients and space so seeds needs to be dispersed away and this is often done by fruits.
Fruits are made attractive to animals to make them take them away. Seeds are either thrown away eg apple core, eaten and have to pass through the gut of the animal before it can germinate, or dropped.