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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. - PowerPoint PPT Presentation
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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).