Asexual Reproduction in Plants
This is simple. A sexual reproduction means to reproduce the same species of organism without the involvement of any gamete cell. Also there is only a single parent involved in this process. The parent involved produces a horizontal shoot called a runner which reaches far away from the parent. At the end of the shoot the runner produces leaves and roots. As the roots develops the runner sags and falls on the ground and soon withers.
Another way is that when humans take small cuttings of the plant and places it in a nutrient rich soil in which new plants are grown.
Scientists involved in this line of work cut a piece of the vegetative part of the plant which can be shorter than a millimeter or even be as small as a single cell. This is then washed and sterilized which is then placed in a solution filled with nutrients. This grows further into a small plant. This can then be grown in a garden.
Sexual reproduction in a Plant
This occurs in a flowering plant. Each flowering plant has a flower. The leaves below the flower is called a sepal and the leaves which make up the flower are called petals which are specialized leaves. The anthers and the filaments of the plant are called stamen which are male parts of the plant while the ovary, style and the stigma are called the carpel which are the female part of the plant.
The anther forms the pollen grain which is the male gamete cell. Its destination is the the stigma through which the grains enter the ovule forming new plants.
However there are several ways it can reach it either by insect or by wind or even by water in the case of underwater plants. If an insect takes the grain to the stigma and the new plant is formed then this would be called self-pollination. But many plants are adapted to cross pollination. The insects or the winds or any other medium of travel would probably take the pollen grain and go to the other flowering plant where the grain is dropped into the ovary and the reproduction takes place.
This has an advantage for the new plant. It is that it is formed of two parents of different genes meaning the off-spring has a slight different genetic material than its parents making it suitable to adapt to the new environment. However, In the case of the asexual reproduction the plant is identical to the parent making it unable to adapt to the change in environment.
Fertilization of Ovary
Now when the seed from the anther reaches the stigma it slowly creates a hollow tube which enters the stigma and extends through the style. After it reaches the ovary it enters it and then enters the ovule. The nucleus of the pollen enters the pollen tube and travels to the ovary. The end of the tube is broken down and the nucleus enters the ovary. The nucleus of the ovary and the pollen combine which fertilizes the ovary. The ovule then turns into a seed according to the size and shape of the ovule and the ovary becomes the main part of the fruit whether a peach or an apple.
The seed is then spread across the land by various means. Either humans interfere and spread the seeds around themselves or when an animal is attracted to the fruit, it picks it and eats it leaving the seed behind to germinate. Some seeds might by pointy and stuck on animal fur while others are carried around on animal feet by mud.
Germination is the process of growth of the seed to a small plant. The structure of the seed is as follows, The seed has a plumule, a radical, a cotyledon, and a testa (seed wall). The cotyledon has various nutrients in it whether a carbohydrate or a protein or starch. When it is ready for the process enzymes are produced which break down the nutrients and use the energy for growth. Slowly the radical moves out of the seed and starts to grow a root which absorbs even more nutrients such as water, potassium, salts etc. The plumule then rises out of the surfaces and starts to build new leaves and a stem.