Plant reproduction is the production of new offspring in plants, which can be accomplished by sexual or asexual reproduction. Sexual reproduction produces offspring by the fusion of gametes, resulting in offspring genetically different from the parent or parents. Asexual reproduction produces new individuals without the fusion of gametes, genetically identical to the parent plants and each other, except when mutations occur.
Asexual Reproduction in Plants
In asexual reproduction male and female gametes do not fuse, as they do in sexual reproduction. Asexual reproduction may occur through budding, fragmentation, fission, spore formation and vegetative propagation. Plants have two main types of asexual reproduction in which new plants are produced that are genetically identical clone of the parent individual. Vegetative reproduction involves a vegetative piece of the original plant and is distinguished from apomixis, which is a replacement of sexual reproduction, and in some cases involves seeds. Apomixis appear in many plant species and also in some non-plant organisms. For apomixis and similar processes in non-plant organisms, see parthenogenesis.
Natural vegetative reproduction is a process mostly found in herbaceous and woody perennial plants, and typically involves structural modifications of the stem or roots and in a few species leaves. Most plant species that employ vegetative reproduction do so as a means to perennialize the plants, allowing them to survive from one season to the next and often facilitating their expansion in size. A plant that persists in a location through vegetative reproduction of individuals constitutes a clonal colony; a single ramet, or apparent individual, of a clonal colony is genetically identical to all others in the same colony. The distance that a plant can move during vegetative reproduction is limited, though some plants can produce ramets from branching rhizomes or stolons that cover a wide area, often in only a few growing seasons. In a sense, this process is not one of reproduction but one of survival and expansion of biomass of the individual. When an individual organism increases in size via cell multiplication and remains intact, the process is called vegetative growth.
In horticulture, a “cutting” is a branch that has been cut off from a mother plant below an internode and then rooted, often with the help of a rooting liquid or powder containing hormones. When a full root has formed and leaves begin to sprout anew, the clone is a self-sufficient plant, genetically identical.
Sexual Plant reproduction
Reproduction in plants takes place sexually and asexually as well. But the majority of the flowering plants reproduce sexually. The flower is the reproductive part of a plant i.e., both male and female gametes are produced by flowers. Sexual reproduction in plants takes place in flowers. The complete flower typically consists of 4 parts:
- Stamen (male reproductive part)
- Pistil/Carpel (female reproductive part)
Stamen consists of anther and filament.
- The anther is a sac-like structure that produces and stores pollen.
- The filament supports the anther.
The pistil (female reproductive part) comprises of three parts- stigma, style, and ovary.
- Stigma is the topmost part of a flower.
- The style is the long tube which connects stigma to the ovary.
- The ovary contains a lot of ovules. It is the part of the plant where the seed formation takes place.
- A flower may consist of either stamen or pistil or both. Based on this, a flower can be either unisexual or bisexual. A bisexual flower is composed of all the four parts mentioned above, e.g. Rose, China rose. Whereas, plants like papaya and cucumber produce only unisexual flowers.