Chapter 1: Asexual Reproduction in Plants (Vegetative Reproduction)

By the end of this chapter, you will be able to:

a) know the meaning of asexual reproduction.

b) understand how plants reproduce asexually.

c) understand that asexual reproduction in plants has important commercial applications.

Keywords

1. adventitious
2. root
3. asexual
4. propagation
5. rhizome
6. runner
7. reproduction
8. scale leaf
9. bud
10. scion
11. budding
12. stock bulb
13. corm
14. grafting
15. internode
16. layering
17. node
18. stolon
19. sucker
20. tuber
21. vegetative
22. reproduction

Introduction

Continuity of living organisms is assured by the fact that they are able to reproduce themselves. Plants can do so by two main ways. That is asexual reproduction or sexual reproduction.

Reproduction is the means by which organisms propagate themselves. New individual organisms are reproduced from their parents. Populations of independent organisms spring up and are able to colonise various and vast communities.

In this chapter you will explore the different ways of how individual plants manage to reproduce themselves asexually and how humans use the knowledge of asexual reproduction in plants to propagate plants artificially.

1.1 Meaning of asexual reproduction

1.1 ActivityFinding the meaning of asexual reproduction

Key question What do you understand by the term asexual reproduction?

What you need

• Pen

• Notebook

Biology dictionary

• Computer with internet connection

• Biology textbooks

What to do

1 In groups, research on the meaning of the term asexual reproduction.

2 Discuss your finding and make a write-up on the term asexual reproduction.

3 Present your findings to the rest of the class and harmonise your work to come up with a proper definition of the term asexual reproduction.

4 Pin up your final explanation of the term asexual reproduction on the noticeboard.

1.2 How plants reproduce asexually

1.2 Activity Identifying plant parts that are used to reproduce asexually

Key question

Which plant parts are used for asexual reproduction?

What you need

• Notebook

· Pen

• Manila paper

Markers

· Computer with internet connection

Biology textbooks

What to do

1 In your group, carry out a field study in the school compound or a nearby area as directed by the teacher

2 Identify the plant parts that are used to get new plants of the same kind.

3 Describe how each of the parts is used to form new plants.

4 Add appropriate drawings to show the parts the plants use to grow other plants.

5 Present your work to the rest of the class, discuss with class members pin up the results on the class noticeboard.

1.3 Methods of artificial vegetative propagation and their use in commercial farming

Naturally plants are able to reproduce themselves as identified in Activity 1.2. Plants do it by a method of reproduction known as asexual reproduction. Scientists have discovered that they can make plants reproduce faster using the same methods artificially.

The methods of artificial reproduction were developed to make plants reproduce in great numbers to boost commercial farming and produce much more food for the continuously growing human population. In this subtopic, you will discover the different methods that can be used in vegative propagation.

Activity 1.3 Researching on methods used in artificial vegetative propagation

Key question

What are the different methods used in artificial vegetative propagation?

What You need

Notebook

Pen

Computer with Computer with internet connection connection

Biology textbooks

What to do

1 In groups research on the different methods that are used to artificially reproduce plants vegetatively.

2 You should take note of the following;

i) Parts that are able to be propagated

ii) Plants that are able to be propagated artificially

iii) The methods being used to propagate plants artificially

iv) Crops that are grown on large scale using artificial propagation in Uganda.

3 Using an appropriate method, prepare a suitable report and present it to the rest of the class.

4 Harmonise your findings with other groups in the class.

5 Pin up your findings on the class noticeboard.

Group project

Grow plants in the school using the methods of layering, marcotting, grafting (stem and bud grafting). Each group is to work on only one crop using only one method. Design your project based on the following: title, objectives of the project, materials required, method of study, recording of observations, discussion of results and present your products to the rest of the class. The duration of the project is one month (4 weeks).

Chapter Summary

In this chapter, you have learnt that: new plants can grow from plant parts and this is one way how plants reproduce. plant parts that give rise to new plants include leaves and stems some of which grow underground. examples of modified stems that can be used for reproduction are tubers, bulbs, corms, rhizomes and suckers. knowledge of asexual reproduction in plants has enabled farmers to grow crops vegitatively example sugar cane, cassava, potatoes, onions, garlic and ginger. gardeners use similar knowledge to propagate decorative plants by applying knowledge of asexual reproduction in plants, humans are able to carry out commercial farming using vegetative propagation methods like marcotting, layering and grafting.

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