Sexual Asexual Reproduction Vegetative Parts in Asexual Reproduction

Sexual & Asexual Reproduction Vegetative Parts in Asexual Reproduction: Presentation 3 of 3

Asexual Reproduction • Asexual or vegetative reproduction involves the production of new plants by means of vegetative parts of an existing plant.

• The vegetative parts of many plants have the ability to produce new roots and/or shoots to form a new plant.

• Asexual reproduction is often advantageous over sexual reproduction because: • new plants reach maturity in less time; • disease-free plants can be produced in controlled environmental conditions;

• reproduction is possible for plants that do not develop reproductive parts or viable seeds; • plant selection for desired characteristics is more reliable; and • new plants are genetically identical to the parent plant.

• Vegetative plant parts used in asexual reproduction include: – Leaves – Stems – Buds – Roots

• Methods of vegetative plant reproduction include: – Cuttings – Layering – Separation – Division – Grafting – Budding – Tissue Culture

Cuttings • Propagation by cuttings is the most widely used method of vegetative or asexual reproduction.

Cuttings Cont’d • A cutting is any part severed from the parent plant, including: • stem cuttings, • root cuttings, and • leaf cuttings.

Layering • Layering involves forcing a vegetative plant part to form roots while still attached to the parent plant.

Types of Layering • Two types of layering are: – Air Layering, which is the process of forcing roots to form on a stem, outside the soil – Ground layering, which is the process of extending a plant part into the ground, covering it with soil, and allowing it to root.

Types of Layering Cont’d

Separation • Separation involves removing new plants formed on specialized stems and separating them from the parent plant.

Division • Division is the technique of cutting specialized plant structures into sections and forcing each section to grow into a new plant.

Grafting • Grafting consists of uniting a hardwood scion from one plant with the rootstock of another similar hardwood plant to form a vascular connection between the two plant parts.

Types of Grafting Techniques • The following techniques could be used in the grafting method.

Budding • Budding, which is similar to grafting, consists of removing buds from one plant and placing them on stems of other closely related plants to form a new plant.

Budding Techniques

Tissue Culture • Tissue culture, or micro-propagation, involves placing a very small piece of plant tissue on a sterilized culture medium. • Under sterile conditions, the plant tissue multiplies and grows into new plants.

Advantages of Tissue Cultures • Advantages of tissue culture as a means of asexual reproduction are that: – It allows large numbers of offspring to be produced quickly – it allows growers to produce disease-free plants; – it is a cost-efficient method of reproducing plants; and – it allows plants to be produced that have the same characteristics as the parent plant.

Disadvantages of Tissue Cultures • Disadvantages of tissue culture include: – The costs of necessary tools and equipment – The preciseness of establishing and maintaining sterile conditions needed for plant development – The requirement of additional time and labor as compared to other methods of asexual propagation.

Summary • Growers use several methods to multiply or increase the numbers of plant species. • Propagation methods can be sexual (reproducing from seeds) or asexual (vegetative production).