Question

Write a note on plant reproduction.

Answer 1

Hint: The process by which living organisms produce offspring is known as reproduction. The process of reproduction is extremely necessary to keep the race of the species going. It is the intrinsic feature of any living organism to keep its race going by reproductive processes. Without reproduction, the species would soon become extinct. Here we are concerned about plant reproduction.

Complete answer:
Plants generally reproduce by two methods:
1. Asexually
2. Sexually
We may discuss the process and types under these two categories for a better understanding.
ASEXUAL REPRODUCTION: -
In this type, the plants do not form any seeds. The vegetative parts of the parent plant give rise to new offsprings. The offspring look exactly equal to the parents and have no genetic variability. Some of the ways in which plants reproduce asexually are discussed below:
Vegetative propagation: New offsprings arise from the plant’s main body. It can occur naturally or can also be done artificially. This method has many types such as:
From underground stems (Tuber in Potato, Rhizome in Ginger, Bulb in Onion); Subaerial stems (Offset in water hyacinth, sucker in Chrysanthemum, Runners in grass); Aerial shoots (Sugarcane); Bulbils (Agave, Oxalis, Ananas)
From leaves as in Bryophyllum.
From roots as in Dahlia.
Artificial methods of vegetative reproduction include plant cuttings, Layering, Grafting, Micropropagation.
Budding: Budding is a process where a small bud from the parent body detaches off and develops into a completely new individual.
Fragmentation: In this mode, the parent body breaks off into many small different pieces. Each of the fragments develop into a new individual.
Apomixis: In this type, the embryo develops from the diploid tissues of the seed other than the egg without fertilization. This is a type of asexual reproduction that mimics sexual reproduction.
SEXUAL REPRODUCTION: -
In this type, two parents- one male and a female are involved. The two plants produce gametes that fuse together to form a new individual. This type of reproduction involves 3 phases:
Pollination and fertilization:
In flowering plants, male and female gametes are produced which are non-motile. Therefore, they need to be brought together for fertilization. The mechanism/process by which this is achieved is known as pollination.
Now the pollen grain upon landing on the stigma develops a pollen tube that grows and ultimately fertilizes the ovum. This process is known as fertilization.
Zygote formation:
The male and the female gamete are haploid. These two eventually fuse to form a zygote which is diploid.
Fruit and seed formation:
Eventually, the ovary gets converted into fruit and ovule into seed.

Note:
Reproduction in plants occur both by both the means- sexual and asexual. But from the evolutionary point of view, sexual reproduction is more preferred. This is so because due to sexual reproduction, genetic variability is introduced in the genome, since both the chromosomes from the male and female gametes combine.
The asexual reproduction generates an individual that resembles exactly the same to the parent.