RBSE Solutions For Class 12 Biology Chapter 4: Special Methods of Plant Reproduction | Textbook Important Questions & Answers

RBSE Class 12 Biology Chapter 4- Special Methods of Plant Reproduction. In this chapter, students can learn in detail about the reproduction in plants, the different types and methods of reproduction in plants. It also deals with apomixis, agamospermy, micropropagation, polyembryony and vegetative propagation in plants.

These important questions help students to perform exceptionally well in their exams. By practising these important questions, students can analyze their preparation, get a thorough knowledge about all the important terminologies and perform their best in the examinations.

RBSE Solutions for Class 12 are the best study material for both class assignments and other board examinations. By practising these important questions, students can gain deep knowledge about the topics explained in this chapter and also help them to be well prepared for their upcoming examinations.

RBSE Class 12 Biology Chapter 4 Important Questions

RBSE Biology Chapter 4: MCQs Type Questions

Q.1. In angiosperms, the reproductive unit is________.

(a)Flower.

(b)Embryo

(c)Seed.

(d)All of the above.

Sol: (c)Seed.

Q.2. The process of developing embryos without fertilization is called________.

(a) Polyembryony.

(b) Adventive embryony.

(c) Gametophytic apomixis.

(d) Sporophytic apomixis.

Sol: (c) Gametophytic apomixis.

Q.3. Who described the different types of Apomixis?

(a) Rudolf Jakob Camerarius.

(b) Frederick Campion Steward.

(c) Wilhelm August.

(d) Professor Panchanan Maheswari.

Sol: (d) Professor Panchanan Maheswari.

Q.4. The process of developing new plants without fertilization is called ________.

(a) Micropropagation.

(b) Syngamy.

(c) Apomixis.

(d) Parthenocarpy.

Sol: (c) Apomixis.

Q.5. Jasmine, Neem,Tubers are examples of _____________.

(a) Artificial Vegetative propagation.

(b) Vegetative propagation by roots.

(c) Vegetative propagation by stem.

(d) Vegetative propagation by buds.

Sol: (d) Vegetative propagation by buds.

Q.6.Which of the following is not the method of natural vegetative propagation?

(a)By Roots.

(b)By Layering.

(c)By leaves.

(d)By Stem.

Sol: (b) By Layering.

Q.7. Which of the following statements are true?

(a)Argemone forms more than one embryo sac in its ovule.

(b)Aristolochia forms more than one embryo sac in its ovule.

(c)Casuarina forms more than one embryo sac in its ovule.

(d)Calotropis forms more than one embryo sac in its ovule.

Sol: (c)Casuarina forms more than one embryo sac in its ovule.

Q.8. Polyembryony is generally found in ________.

(a) Monocotyledons

(b) Angiosperms

(c) Dicotyledons

(d) Gymnosperms

Sol: (d) Gymnosperms

Q.9. Which of the following are methods of vegetative propagation in plants?

(a) Budding.

(b) Grafting.

(c) Cloning.

(d) All of the above.

Sol: (b) Grafting.

Q.10. Apomixis in flowering plants are divided into ________ types.

(a)Two.

(b)Three.

(c)Four.

(d)Five

Sol: (c)Four.

Q.11. Corn and onions are examples of _____________

(a) Artificial Vegetative propagation.

(b) Bread wheat.

(c) Hydrilla.

(d) Natural Vegetative propagation.

Sol: (d) Natural Vegetative propagation.

Q.12. Which of the following methods is used in the large scale production of plants?

(a) Apomixis.

(b) Agamospermy.

(c) Micropropagation.

(d) Vegetative propagation.

Sol: (c) Micropropagation.

Q.13. The occurrence of more than one embryo in one ovule is called ________.

(a)Polyembryony.

(b)Monocotyledons .

(c)Angiosperms.

(d)Dicotyledons.

Sol: (a)Polyembryony.

Q.14. The process of multiplying plant stock plant material by growing plantlets is called ________.

(a) Apomixis.

(b) Agamospermy.

(c) Micropropagation.

(d) Vegetative propagation.

Sol: (c) Micropropagation.

Q.15. Hybrids seeds may be easily produced by the process of ________ .

(a) Apomixis.

(b) Agamospermy.

(c) Micropropagation.

(d) Vegetative propagation.

Sol: a) Apomixis.

Q.16. ________ is an example of stem cutting- an artificial method of vegetative propagation?

(a) Mango.

(b) Lemon.

(c) Jasmine.

(d) Sugarcane.

Sol: (d) Sugarcane.

Q.17. The process of developing embryos from an unfertilized egg is known as as_________.

(a) Apomixis.

(b) Agamospermy.

(c) Parthenogenesis.

(d) Vegetative propagation.

Sol: (c) Parthenogenesis.

Q.18. Meiosis does not occur in the process of_________.

(a)Agamospermy.

(b)Apomixis.

(c)Micropropagation.

(d)Vegetative propagation.

Sol: (b)Apomixis.

Q.19. Which part of the plant is not used for the vegetative propagation?

(a) Flower.

(b) Seeds.

(c) Roots.

(d) Leaves.

Sol: (d) Leaves

Q.20. Formation of seed without fertilization is called _________.

(a)Apomixis.

(b)Agamospermy.

(c)Micropropagation.

(d)Vegetative propagation.

Sol: (b)Agamospermy.

RBSE Biology Chapter 4:Short Answer Type Questions.

Q.1. Define special methods of reproduction in plants?

Sol. The special methods of reproduction in plants are defined as a process of producing new plants through the sexual mode of reproduction, without the process of fertilization. This method includes the following four different processes:

  1. Apomixis.
  2. Agamospermy.
  3. Micropropagation.
  4. Vegetative propagation.

Q.2.What is the main advantage of micropropagation?

Sol: Micropropagation helps in the propagation of a large number of plants in a very short time. The plantlets produced are healthy and with desired characteristics. It is the most useful and modern method of plant breeding and is widely used for the production of medicinal plants, wild plants and other commercially important plants on a large scale.

Q.3. What is Apomixis?

Sol: Apomixis, is also called the asexual mode of reproduction in plants. In this method of reproduction, the ovary develops into a fruit without fertilisation. This process was defined by Hans Winkler. According to his research, apomixis is a replacement of the normal sexual reproduction by asexual reproduction, without fertilization.

Q.4. List out the types of Natural Vegetative Propagation.

Sol. The different types of natural vegetative propagation are as follows:

  1. Vegetative propagation by roots.
  2. Vegetative propagation by stems.
  3. Vegetative propagation by leaves.
  4. Vegetative propagation by reproductive organs.

Q.5. What is Micropropagation?

Sol: Micropropagation is the artificial process of producing plants vegetatively through tissue culture or cell culture techniques. In this artificial process of propagation, plants are produced in-vitro by asexual means of reproduction or by vegetative propagation.

Q.6. Define Recurrent Apomixis and Non-recurrent Apomixis

Sol:

Recurrent Apomixis– In recurrent apomixis, both the egg-cell and embryo are diploid and the embryo-sac is developed from the megaspore mother cell.

Non-recurrent Apomixis —In non-recurrent apomixis, both the egg-cell and embryo are haploid and the embryo is developed directly from an egg-cell without fertilization.

Q.7. What are the main causes of Polyembryony?

Sol: The main causes are:

  1. The cleavage of an embryo
  2. Development of more than one embryo sac in an ovule.
  3. Development of an embryo from any other cell of embryo sac.

Q.8. Give any two importance of Micropropagation?

Sol: Importance of Micropropagation is:

  1. Micropropagation helps in the production of large quantities of plants within a very short time period.
  2. Micropropagation is an alternative method for vegetative propagation with enhanced multiplication rate.

Q.9. What is Crown Grafting and Bud Grafting?

Sol:

Crown Grafting — In this method of grafting the selected stock is many times thicker than the scion. Therefore, more scions are grafted on the stock.

Bud Grafting — In this method of grafting the bud is grafted on the stock. A T-shaped cut is made in the bark of the stock plants, then the selected bud is grafted on the stock and both are tightly tied together.

Q.10. What is Vegetative propagation?

Sol: The asexual method of producing plants with the help of its leaves, roots and stem is termed as vegetative propagation. This process occurs through fragmentation and regeneration of specific vegetative parts of plants.

Q.11.What is gametophytic and generative apomixis?

Sol. Gametophytic apomixis is the type of apomixis, where an embryo is developed from a haploid cell of embryo sac.

Generative apomixis is the type of apomixis, where embryo sac is developed from the diploid cells of archesporium – the group of cells from which spore mother cells develop.

Q.12.What is Cleavage Polyembryony?

Sol: : The development of many embryos from a single fertilized egg in plants are termed as Polyembryony. Cleavage Polyembryony is the type of a polyembryony, where more than one embryo develops into a seed by the cleavage of zygote. This is one of the main reasons for the formation of polyembryony in a seed.

Q.13. How is a sugarcane plant produced from the process of vegetative propagation?

Sol. Sugarcane plants are produced from the vegetative propagation by stem. In this process of propagation, the stem of disease-free sugar cane plants are selected and their cuttings are planted into the soil.

Q.14.What is Agamospermy?

Sol: Agamospermy is an asexual mode of reproduction in plants. In this process, the seeds are formed without fertilization. i.e., without the fusion of gametes or sex cells and the meiosis process. Offspring produced through agamospermy are generally identical to the parent plant.

Q.15.Give examples of plants growing with the vegetative propagation by stem.

Sol. Potatoes, ginger, onions, garlic, tulips, mint, strawberry and all other tubers are examples of plants growing with the vegetative propagation by stem. These plants are produced from the modified stem.

Q.16. Explain the cleavage polyembryony in an orchid?

Sol: In orchid, also called as Eulophia, three types of cleavage polyembryony develops:

  1. The embryos are developed from the irregular divisions in the zygote.
  2. The embryos are developed from the buds or its outgrowths develop from the proembryo.
  3. The embryos are developed from the branches of proembryo. It is also called a filamentous embryo.

Q.17. What is Air Layering?

Sol: Air layering is the artificial method of vegetative propagation, which are mainly used for thick-stemmed houseplants, which have lost their lower leaves and have become leggy. Citrus trees are the best examples of plants that can be propagated by air-layering.

Q.18. Explain the types of vegetative propagation.

Sol: There are two different types of vegetative propagation:

Natural Vegetative Propagation–This is a type of vegetative reproduction naturally without any human interference.

Artificial Vegetative Propagation –This is a type of vegetative reproduction carried out by humans on the fields and laboratories.

Q.19.What is Vegetative Apomixis?

Sol. Apomixis is also called the asexual mode of reproduction in plants. Vegetative apomixis is a type of apomixis, where vegetative bulbils or buds are produced in the inflorescence instead of flowers.

Q.20. List out the importance of Polyembryony.

Sol: The importance of polyembryony is:

  1. Adventive embryos developing from nucellus are similar to the parent plants.
  2. Plants obtained from the embryos and developed by the nucellus are full of vigour.
  3. Embryos developed from nucellus are free from all types of infections and diseases. Therefore, disease-free and varieties of clones can be obtained.

RBSE Biology Class 12: Long Answer Type Questions

Q.1.What is Micropropagation? Write the advantages of Micropropagation?

Sol. Micropropagation is the artificial process of producing plants, vegetatively through tissue culture or cell culture techniques. In this artificial process of propagation, plants are produced in-vitro by asexual means of reproduction or by vegetative propagation.

In this method of micropropagation, plants can be propagated both sexually and asexually. In the sexual method of micropropagation, plants are propagated through the generation of seeds and in the asexual method of micropropagation, plants are propagated by clonal propagation or by multiplying genetic replicas of plants.

The advantages of micropropagation in plant production are as follows:

  1. It is a cost-effective process.
  2. New varieties of species can be propagated.
  3. This process requires very less space and human resources.
  4. Millions of plantlets can be maintained in the cultural vials.
  5. This method helps in obtaining the desired sex of the plant.
  6. An identical plant can be obtained from single plant tissue.
  7. The small-sized propagules can be stored and transported easily.
  8. This method is independent of season and can be carried out anytime.
  9. It helps in the production and maintenance of pathogen-free plant varieties.
  10. The germplasm stocks can be preserved for several years using this technique.

Q.2.What is the difference between Apomixis and Polyembryony?

Sol. There is a minute difference between Apomixis and Polyembryony.

Apomixis Polyembryony
An asexual reproduction that occurs without fertilization and not involving meiosis. The formation of more than one embryo from a single fertilized ovum or in a single seed.
Undergoes asexual mode of reproduction. Undergoes sexual mode of reproduction.
Formation of embryos. Formation of two or more embryos.
Fertilization does not occur in apomixis. Polyembryony undergoes fertilization.
Not involved in the production of seeds. Involved in the production of seeds.
The plants produced by apomixis are genetically-identical to the parent. The plants produced by polyembryony are not genetically identical to the parent.

Q.3.What is Vegetative propagation? List out the advantages of vegetative reproduction.

Sol. The asexual method of producing plant with the help of its leaves, roots and stem is termed as vegetative propagation. This process occurs through fragmentation and regeneration of specific vegetative parts of plants.

There are two different types of vegetative propagation:

  1. Natural Vegetative Propagation
  2. Artificial Vegetative Propagation.

There are several advantages of vegetative reproduction. Listed below are a few of them:

  1. Vegetative propagation helps plants in the development of sex organs such as flowers, fruits and seeds.
  2. Vegetative propagation is more economical for the plants, compared to other methods of cloning.

Plants produced by vegetative propagation are of superior quality.

Q.4. Explain the different types of Apomixis in flowering plants.

Sol: In flowering plants, apomixis is divided into four main types:

  1. Non-recurrent Apomixis —In non-recurrent apomixis, both the egg-cell and embryo are haploid and the embryo is developed directly from an egg-cell without fertilization.
  2. Recurrent Apomixis– In recurrent apomixis, both the egg-cell and embryo are diploid and the embryo-sac is developed from the megaspore mother cell.
  3. Adventive embryonic–Adventitious embryonic is most commonly initiated apomixis. In this process, embryos initiate parthenogenetically outside of an embryo sac structure.
  4. Vegetative Apomixis–In this apomixis type, vegetative bulbils or buds are produced in the inflorescence instead of flowers.

Q.5. What is Polyembryony? Explain the causes of polyembryony in angiosperms.

Sol: The development of many embryos from a single fertilized egg in plants are termed as Polyembryony. This type of natural phenomenon is also found both in animals.

The production of two or more than two embryos from a single seed is termed as Polyembryony. In plants, this phenomenon is caused either due to the fertilization of one or more than one embryonic sac or due to the origination of embryos outside of the embryonic sac.

This natural phenomenon was first discovered in the year 1719 by Anton van Leeuwenhoek in Citrus plant seeds.

The causes of polyembryony in angiosperms develops due to the following reasons:

  1. By the cleavage of an embryo.
  2. By activity of sporophytic cells of the ovule.
  3. By the development of more than one embryo sacs in an ovule.
  4. Due to the development of an embryo from any other cell of embryo sac simultaneously with that of an egg cell.

Q.6. What is Apomixis? List out the importance of Apomixis.

Sol: Apomixis, is also called the asexual mode of reproduction in plants. In this method of reproduction, the ovary develops into a fruit without fertilisation. This process was defined by Hans Winkler. According to his research, apomixis is a replacement of the normal sexual reproduction by asexual reproduction, without fertilization.

The importance of apomixis in plant production are as follows:

  1. It is a cost-effective process.
  2. It helps in hybrid seed production.
  3. It prevents the loss of specific characters in the hybrid.
  4. It helps in developing new plants without fertilization.

In this process, seeds are formed by asexual reproduction, therefore the clonal offsprings are similar to the mother plant.

Q.7. Define the following terms:

  1. Grafting.
  2. Cutting.
  3. Layering.

Sol:

  1. Grafting — Grafting is an artificial vegetative propagation method used to combine sections of two or more plants in a single plant. The different types of Grafting are tongue grafting, wedge grafting, crown grafting and bud grafting.
  2. Cutting–Cutting is a type of artificial vegetative propagation. In this method of propagation, a small part of a parent plant is cut and replanted in the soil after being treated with all essential plant growth hormones. After a few days, new plants or adventitious roots develop from the cuttings. Stem cutting and root cutting are two different types of cuttings in plants.
  3. Layering– Layering is the artificial methods of vegetative propagation in plants. In this method, a stem is attached to a plant, is lowered in the ground and covered with soil. The stem grows roots while attached to the parent plant and then detaches as an independent plant. The best time to perform layering is when the plant is in its dormant stage. Mound and air layering are different types of layering in plants.

Q.8. Brief out in detail about the natural vegetative propagation.

Sol. Natural vegetative propagation is a type of plant propagation or reproduction, which occurs when plants grow and develop naturally without any human intervention. The most common methods of Natural vegetative propagation are:

Vegetative propagation by roots: Sweet potato, Tapioca, yam, Dahlia and Tinospora are examples of plants produced by roots.

Vegetative propagation by stems: Onions, Garlic, and Tulips are examples of plants produced by stems.

Vegetative propagation by leaves: Sansevieria African Violets are examples of plants produced by leaves.

Vegetative propagation by reproductive organs: Agave, wild yam and purple yam are examples of plants produced by reproductive organs.

Q.9. Brief out in detail about the asexual reproduction in flowering plants.

Sol. The asexual method of reproduction in flowering plants does not involve meiosis and fertilization. It is also known as apomixis. In this process of reproduction in plants, mitotic cell divisions are involved in these methods, which results in the formation of offspring which are genetically similar to the parent plant.

The different types of asexual method of reproduction in flowering plants are as follows:

Agamospermy.

Agamospermy is an asexual mode of reproduction in plants. In this process, the seeds are formed without fertilization. i.e. without the fusion of gametes or sex cells and the meiosis process. Offspring produced through agamospermy are generally identical to the parent plant.

Micropropagation.

Micropropagation is the artificial process of producing plants, vegetatively through tissue culture or cell culture techniques. In this artificial process of propagation, plants are produced in-vitro by asexual means of reproduction or by vegetative propagation.

Vegetative propagation.

The asexual method of producing plants with the help of its leaves, roots and stem is termed as vegetative propagation. This process occurs through fragmentation and regeneration of specific vegetative parts of plants. There are two different types of vegetative propagation – Natural Vegetative Propagation and Artificial Vegetative Propagation.

Q.10.What are the similarities and differences between Agamospermy and Apomixis?

Sol.

The similarities between agamospermy and apomixis are:

  1. Both agamospermy and apomixis undergo asexual mode of reproduction.
  2. Both agamospermy and apomixis do not involve in the production of gametes.
  3. Both agamospermy and apomixis produce genetically identical offspring to their parents.

The differences between agamospermy and apomixis are:

Agamospermy Apomixis
Occurs predominantly in gymnosperms. Occurs predominantly in angiosperms.
They produce clonal seeds. They replace the flower vegetative parts.
There are two types of agamospermy. There are four types of apomixis.

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