Asexual reproduction of a flowering plant

Vegetative PropagationAsexual Reproduction in Plants

DefinitionAsexual reproductiondoes not involve the manufacture or union of sex cells or gametes e.g. binary fission, fragmentation, spore formation and budding It involves only one parent and offspring are genetically identical (have the same genetic content) to the parent

Vegetative PropagationA form of asexual reproduction in plantsDoes not involve gametes, flowers, seeds or fruitsOffspring are produced by a single plant (genetically identical to parent)Can happen naturally or it can be done artificially

Natural e.g. runners, tubers, plantlets, bulbsVegetative Propagation

What happens?Part of the plant becomes separated from the parent plant and divides by mitosis to grow into a new plantAs a result the offspring are genetically identical to the parent

Parts of the parent plant may be specially modified for this purpose:StemRootLeafBud

Modified StemsRunnershorizontal, running over the soil surfaceterminal bud of the runner sends up new shoots e.g. strawberry, creeping buttercup.

Modified Stem (continued)Stem Tubersswollen underground stem tipsbuds (eyes) produce new shoots e.g. potato

2. Modified RootsRoot Tuberswollen fibrous roots the tuber stores food, but the new plant develops from a side bud at the base of the old steme.g. dahlia, lesser celandine

Note:Tap Roots e.g. carrot and turnip, are swollen roots for food storage in biennial plants… they are not reproductive organs

3. Modified Leaves PlantletsSome plants produce plantlets along the edges of the leavesPlantlets reach a certain size, fall off and grow into new plants e.g. Lily, kalanchoe(mother of thousands)

4. Modified BudsBulbs A bulb contains an underground stem, reduced in sizeLeaves are swollen with stored foode.g. onion, daffodil, tulip

4. Modified Buds BulbsThe main bud (apical bud) will grow into a new shoot)The side buds (lateral buds) will also grow into new shoots

Comparison of reproduction by seed (sexual) and by vegetative propagation (asexual)

Advantage to vegetative propagation

Artificial used by gardeners to propagate plants e.g. cuttings, layering, grafting and buddingVegetative propagation

CuttingsParts of a plant (usually shoots) removed from plant allowed to form new roots and leavesrooted in water, well-watered compost, or rooting powdere.g. busy lizzie, geranium

GraftingPart of one plant (scion) is removed and attached to a healthy, rooted part of a second plant (stock)Useful qualities from both plants combined into one e.g. rose flower and thorn-less steme.g. apple trees

LayeringA branch of a plant is bent over and pinned to the earth at a node When roots develop the branch is separated from the parent plant. Useful for the propagation of woody plants e.g. blackberry, gooseberry.

Micropropagation (Tissue Culture) (1/3)Cells removed from plant and grown as a tissue culture in a special mediumGrowth regulators and nutrients added so that growing cells form a group of similar cells called a callus

Micropropagation (Tissue Culture) (2/3)Different growth regulators are then added so that this tissue develops into a plantlet Plantlet can be divided up again to produce many identical plantsEntire plant can be grown from a small piece of stem, leaf or root tissueUsed in mass production of house plants and crops such as bananas and strawberries

Micropropagation (Tissue Culture) (3/3)Provides a larger number of plants more quickly than cuttings.Can be used to check cells for a particular feature e.g. resistance to chemicals or a particular disease

CloningAlloffspring genetically identical - produced asexually Clones are produced by mitosisAll the offspring from the various methods of vegetative reproduction (both natural and artificial) mentioned are examples of clones

Asexual reproduction of a flowering plant

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Asexual reproduction of a flowering plant