Question

Which of the following plants shows self-sterility?
A.Tobacco
B.Potato
C.Crucifers
D.All of the above

Answer 1

Self sterility is the term used to describe a condition in bisexual plants wherein the plant is incapable of producing fertilized seeds when they are self-pollinated but can be pollinated by other methods such as artificial or insect pollination. This condition was first seen in the tobacco plant and later in potatoes and crucifers.

Complete answer: Self-sterility is a term used to describe bisexual plants which cannot fertilize or set seeds on their own. This is a condition wherein the pollen from the same plant does not germinate on the stigma. This was first reported in Nicotiana (tobacco), where there was no seed setting in isolated tobacco plants. This is also seen in the case of potatoes and crucifers.
The mechanism of sterility is different in the case of tobacco, potato, and crucifers. In tobacco, pollination does not occur due to the presence of a membrane of the stigma which prevents the growth of the pollen tube to the ovule.
In the case of potato, it is known as male sterility, where the anthers cannot produce enough pollen grains or cannot produce pollen grains at all. And in the case of crucifer, the stigma prevents pollen tube formation for self-pollens and only germinates if pollen from a genetically different species lands on the stigma.
The main reason for self-sterility is to prevent inbreeding and improving the genetic variation of plants.
Self-sterility can be eliminated by artificial pollination and other genetic and mechanical techniques.
Thus, the correct option is D, all of the above.

Note: Self-sterility when plants are incapable of self-pollination.
This can be achieved by affecting any stage of the reproductive process
This is due to the presence of an additional membrane in tobacco, that prevents the germination of the pollen tubes and fertilization of pollen with the ovules.
In potatoes, it is due to a lack of anther development and pollen production.
It crucifers it due to a lack of pollen formation due to self-incompatible pollen grains.
Self-sterility is a mechanism evolved to prevent inbreeding in plants.