The process by which the production of new individuals occurs from its parents is termed reproduction. In the case of plants, they undergo the same reproduction process to produce new individuals and it is inherited features that are present in all living organisms. By this process, organisms are able to maintain their races. There are different modes of reproduction that are seen in different animals and the same is with plants also.
For determining the genetic constitution of a plant and finding out its characteristic features, knowing the mode of reproduction is necessary. If we carefully see plants we will notice that they consist of different parts where each part performs its specific function. These parts may be categorized into two types one is the vegetative part: leaves, roots and stem and the other is reproductive, which include flowers. So, the major part of plants that perform the reproduction process is flowers. During the process of reproduction in plants, the male parts and the female parts are brought in contact and then fusion of gametes takes place which further produces food that bears seeds. Further these seeds undergo a germination process to give birth to new plants. Along with that some plants also have the capability to give rise to a few plants with the help of their vegetative parts like buds, stem, leaves, etc.
Asexual Mode of Reproduction: In this mode of reproduction, plants give rise to new individuals without any involvement of male and female reproductive parts of plants. In such reproduction, no fruit and seed is seen in plants.
Further asexual reproduction is categorised into different types, they are:
Vegetative Propagation: In this type, new plants are produced from a certain portion of plants. It can be done both with natural process or artificial method. For example, the production of onion bulbs is a natural process whereas rose plants are grown by artificial methods of propagation.
Budding: In this mode, new plants are grown from a bud, which is a kind of outgrowth present in the plant body.
Fragmentation: In this mode of reproduction, new plants are produced from the fragments which are present in the plant body.
Apomixis: It is mode seeds are formed and the development of the embryo takes place without fusion of male and female gametes. One of the common examples of plants that show this mode of reproduction is the Citrus tree.
Sexual Mode of Reproduction: In this mode of reproduction new plants are formed by the development of embryos which is formed by the fusion of male and female gametes. Fruits of such plants bear seeds and further these seeds give rise to new plants.
The process of reproduction can be both sexual and asexual but most of the plants undergo a sexual mode of reproduction. The main reproductive part of the plant is flowers i.e. they produce both male and female gametes.
It is the male reproductive part which is further made up of two parts, they are - anther and filament. Anther is a sac like structure which mainly does the function of production and storage of pollen. Whereas filaments perform the function of giving support to the anther.
It is a female reproductive part of plants that further comprises three parts they are: stigma, style, ovary. Stigma is known to be the topmost part of the flower, followed by the style which is a long tube that connects the stigma to the ovary. The ovary is a part that contains ovules and it is the part of the plant where the formation of seeds takes place.
Based on the presence or either stamen or pistil or both, we can categories plant into unisexual or bisexual. A bisexual flower is made up of all four parts. Example of bisexual plants is: china rose, rose, etc. Whereas examples of unisexual flowers are papaya, cucumber and many more.
There are three crucial steps which plant undergoes during sexual reproduction:
Pollination: It is the process during which there occurs transfer of pollen grain from anther to stigma, among the same flowers or flowers of different plants. Based on this transfer among the same or different plant pollination is of two types i.e. self pollination and cross pollination.
Zygote Formation: After the first step i.e. after the transfer of pollen grains, there occurs transfer of male gamete down through the style of the pistil to the ovary to the place where the fusion of male gamete to female takes place for the formation of zygote.
Fruit and Seed Formation: Once fertilization is over, formed zygote is developed into an embryo. Further ovaries develop into fruit and ovules develop into seeds.
1. Explain different types of pollination in plants?
For the formation of a zygote, the fusion of male gametes present in pollen grain and egg is the ovule is a must. Thus it can be said that pollination is a process of transfer of pollen grains from anther to stigma.
Based on transferring of pollen grains i.e. landing of pollen grains pollination are of two types:
Self-Pollination: In this type of pollination, the transfer of pollen grain from another stigma of the same flower takes place.
Cross-Pollination: In this type of pollination transfer of pollen grain from another to the stigma of the same plant or of the different plant but of the same species takes place.
2. Explain the term pollinating agents?
The agents which are actively involved in transferring pollen grains from another to the stigma known as pollinating agents. Some of the common pollinating agents are: animals, birds, insects, wind and other biotic and abiotic agents are all examples of pollinating agents.