NCERT Solutions for Class 12 Biology Chapter 2
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FAQs on NCERT Solutions for Class 12 Biology Chapter 2 - Sexual Reproduction In Flowering Plants
1. If a person can induce the process of parthenocarpy through growth substances, which fruits need to be selected?
The parthenocarpy fruits are seedless, and they can be easily developed from the plant's ovary without undergoing fertilization. Thus, one can use grapes, bananas, lemon, pineapple, and guava are the fruits that can be used for the said process. These fruits are seedless and considered to be economical fruits developed through the said process. The technique of parthenocarpy includes the principle of inducing the desired fruit formation through the application of different plant growth hormones, for example, auxins.
2. What do you mean by emasculation?
Emasculation is the process of removing the stamens or the anthers of bisexual flowers. However, during the process, the female reproductive organs are not at all affected. This said technique is known by the name of artificial hybridization. However, when doing such experiments, it is imperative to understand that one should use only desired pollen grains and the stigma of the flower should be protected effectively from the contamination from any kind of unwanted pollen.
3. How does self-incompatibility restrict autogamy? How does pollination occur in such plants?
Self-incompatibility prevents autogamy through a process called self-sterility. It is a genetic technique with the help of which the process of germination of the pollen grains or the growth of the pollen tube is inhibited. This way the pollen cannot fertilize the ovules. These kinds of plants pollinate through a process called cross-pollination. To get an elaborate explanation about crop pollination, visit Vedantu website or Vedantu Mobile app. The solutions provided by Vedantu are free of cost.
4. Please explain polyembryony.
If more than a single embryo is present in one seed, the phenomenon is known as polyembryony. It is usually seen in some varieties of citrus fruits as well as mango. It plays a crucial role in the breeding of plants and horticulture. These embryos can give birth to healthy plantlets free of viruses. Hybrid species of these plants and fruits are grown extensively nowadays. The varieties obtained through this method are extremely productive.
5. What is the difference between apomixis and parthenocarpy?
In parthenocarpy, fruit can be produced even if the female gamete is not fertilized. This process is utilised for producing seedless fruits like bananas and grapes in the commercial field.
In apomixis also, the seeds can be produced with no fertilization but the whole process takes place in the reproductive tract of the female plant. Here, a megaspore mother cell need not undergo meiosis. This process helps in producing hybrid and virus-free varieties.
6. Elaborate on the disadvantages of self¬pollination?
There are a few significant disadvantages of the process of self-pollination:
Reducing vigour in the plants that are produced with self-pollination.
Decrease in the yield.
The number and size of the seeds continue to decrease with l generations.
Plants are vulnerable to diseases.
7. Define ornithophily, chiropterophily and malacophilous?
The definition are as follows:
Ornithophily is when pollination is carried out with the help of small birds.
Eg: Australian plants.
Chiropterophily refers to pollination with the help of bats.
Eg: Sausage tree.
Malacophily is the process of pollination with the help of Snails