Vegetative Propagation Flashcards
What is vegetative propagation?
Vegetative propagation is a form of asexual reproduction and results in new plants which are all clones of the parent plant. (called a stock plant) ‘Vegetative’ means all types of propagation APART FROM THE SEED.
What type of plant species are suitable for vegetative propagation?
Perennials
Biennials & Annuals do not propagate this way.
Where are the plant cells produced?
Plant cells are produced in plant meristems where cells multiply by dividing.
These new plant cells are influenced by PGRs (plant growth regulators) that determine what they develop into eg root cells.
What is the ‘cut away’ part of the plant in vegetative propagation called?
A propagule
Where should you make a cut on a stem for vegetative propagation?
Just below a leaf node or across vascular bundles where meristematic tissues can produce large quantities of new cells to generate these new plant parts. Eg. roots developing on a stem cutting.
What are the benefits of vegetative propagation to the plant?
Vegetative propagation is more reliable than the two ‘hit and miss’ processes of pollination and fertilisation.
What are the benefits of vegetative propagation to the horticulturalist?
Retains characteristics of the parent plant.
Obtain a mature plant quicker than using seed for hardwood cuttings/division.
Avoids seed dormancy problem.
Is the only possible method for some plants - some plants do not produce viable seed.
Can cost less - sometimes just labour eg. with division and replanting.
What are the limitations of vegetative propagation to the plant?
No genetic diversity
If things go wrong all die-no survival of the fittest.
Pests and diseases are passed on.
What are the limitations of vegetative propagation to the horticulturalist?
Availability of plant material.
Root cuttings difficult to collect enough material to make it financially viable whereas leaf bud cuttings has much more potential.
Lack of variation in the resulting plant.
Transmission of disease.
Requirement of different skills compared to seed sowing. Damage to the stock plant.
Requirement for different propagation equipment - eg. mist units, heated benches.
A pest of disease issue could wipe out entire population as all clones.
Smaller number of plants are obtained than from seed.
Some may involve more expense due to skilled labour and equipment.
Name 9 methods of natural vegetative propagation?
- Bulbs - Narcissus ‘February Gold’
- Corms - Crocus sativus
- Rhizomes - Iris germanica
- Stolons - Fragaria x ananassa
- Stem tubers. - Solanum tuberosum
- Root tubers - Dahlia ‘Bishop of Landaff’
- Tip layering - Bramble Rubus Fruticosus
- Stem suckers.- Rhus typhina
What are the natural methods of propagation a bulb uses?
Bulbs eg Narcissus ‘February Gold’ Modified leaves that naturally multiply with offsets called bulbils developing from the basal plate. This is how a clump of daffodils or snowdrops grows bigger.
What are the natural methods of propagation a corm uses?
Corms eg Crocus sativus - Modified stem. Before it withers away at the end of the growing season a new corm (sometimes several new corms) forms and replaces the mother corm. New cormels or cormlets also form around the edge and develop into new plants.
What are the natural methods of propagation a rhizome uses?
Rhizomes eg Iris germanica - modified stems that lengthen through the soil, rooting and forming shoots at nodes and can break off to form new plants. Equisetum arvense (Horsetail)
What are the natural methods of propagation a stolon uses?
Stolons/runners eg Fragaria × ananassa / Ranunculus repens- modified stem that grows above ground and roots into ground at nodes. Once established stolon may wither away giving two separate plants.
Give an example of a stem tuber and how it creates a new plant?
Stem tubers eg Solanum tuberosum newly developed stem tubers can disconnect from the parent plant and become a new plant.
How can you get new plants from Dahlias?
Root tubers eg Dahlia ‘Bishop of Llandaff’ - newly formed root tubers can again disconnect from parent plant (in nature this happens far less in root tubers than in stem tubers but is a process gardeners can harness to propagate new plants).
Give a plant example for tip layering?
Tip layering. Eg Bramble Rubus fruticosus. Long flexible stems bend to the ground and root at the tip.
Give a plant example for a stem sucker natural propagation method?
Stem Suckers eg Rhus typhina May break away from the parent plant once established.
Give 6 methods of artificial vegetative propagation? (they do not happen naturally)
Division Air layering Stem cutting Leaf bud cuttings Leaf petiole cuttings Grafting
Give 2 plant examples which can be lifted and divided?
Alchemilla mollis
Hosta ‘Golden tiara’
Give 2 plant examples which can be air layered?
Ficus elastica
Camellia japonica
Give 2 plant examples you can do stem cuttings with?
Cornus alba ‘Siberica’
Lavandula augustifolia
What plant can you do a leaf bud cutting with?
Camellia japonica
Give a plant example you can do a leaf petiole cutting with?
Saintpaulia ioantha (African violet)
What is juvenile growth?
Juvenility = juvenile growth is young non-reproductive growth ie vegetative (leafy) rather than reproductive adult growth which is flowering / fruiting.
What defines a healthy plant?
Free from pest & disease.
Nutritionally satisfied
Grown in correct light levels
Not lacking in water availability
Why is juvenile growth ideal for vegetative propagation?
Juvenile growth is ideal for vegetative propagation as the PGRs in mature growth inhibit root formation (mature plants are in ‘flowering mode’ not ‘rooting and leaf growth’ mode).
Thus juvenile growth has the ability to form new roots and / or new stems
What characteristics must the cutting material have?
Juvenile
Healthy
True to type
Cells must be turgid (no signs of wilting) so collect early in the morning
Why should you collect cutting material early in the morning?
Cells must be turgid (no signs of wilting) so collect early in the morning because the stomata have been closed all night and if water is available at the roots the cells will be turgid. After collection put cuttings straight into a plastic bag and store in a cool place until cuttings can be inserted into growing medium.
How can you make sure you know which is the top and bottom of your cutting?
Polarity needs to be maintained. Straight cuts at the bottom, and slanted cuts at the top.
What factors do you need to make sure of when taking cuttings?
Sterile clean tools.
Pest & disease free
Take cuttings at correct time of day
True to type
Ensure ‘mother plant’ is in good healthy condition.
Juvenility of cutting material eg. non flowering, or flower buds removed.
Correct hardness of wood for particular plant or stage of cutting. (eg.softwood and hardwood stem cuttings)
Time of year will influence success of cuttings. Eg. spring/early summer
What growing medium might you need when doing vegetative propagation?
Compost - peat free
Perlite
Sand/grit
Mix 50% compost with 50% perlite or sharp sand.
John Innes seed sowing/cuttings compost is a readymade mix of sharp sand and compost suitable for cuttings/seeds.
What 5 factors need to be managed in the propagation environment?
Temperature Light levels Relative Humidity Moisture/Drainage Air flow
Why does temperature affect the success of vegetative propagation?
Warmth increases rate of cell division and root formation thus aiding rapid rooting.
When doing cuttings where should you direct the heat?
Want heat/warmth applied at the bottom of cutting (bottom heat) & tops to be cooler
How can you monitor the ambient temperature in a greenhouse?
With a thermometer.
What equipment can be used for managing the temperature for vegetative propagation?
Soil warming cables, heated mat, heated propagator, heated glasshouse
Why are moisture levels so important in propagating vegetative cuttings?
Until roots are formed, cutting is under a lot of water pressure as water continues to be lost from the leaves yet no roots exist to absorb water.
In waterlogged conditions cutting may rot.
What methods can be used to manage moisture levels when taking vegetative cuttings?
Mist bench, cover of plastic eg as in propagator to retain humidity around cuttings
Drainage through addition of grit / sand to media
Why is it important to manage the airflow in the growing space when propagating vegetative cuttings?
Insufficient airflow can cause fungal problems.
Too much air flow can dry them out.
What can you do to help maintain a good air flow in your growing environment?
Automatic vents / vented lids of a propagator
Spacing cuttings appropriately.
What must you do in the aftercare of the propagules?
- Monitor P & D (pest & disease)
- Manage moisture levels
- Maintain nutrition by feeding
- Remove dead foliage
- Harden off (acclimatize gradually to the outdoor environment)
- Pot on to more nutrient rich compost
Give 4 examples of where you can propagate cuttings?
Cold Frame
Mist bench
Heated propagator
Open ground
Describe what a cold frame is and how it can be used for propagation?
Cold frame is an unheated, small enclosed unit usually with a glass or perspex lid which can be opened or closed.
It is used for hardwood cuttings in pot, division propagules, root cuttings, semi ripe cuttings of shrubs or conifers.
It is used to protect the cuttings from the extreme cold and wind and rain.
It can also be used to harden off more advanced propagules grown in a protected environment before planting out.
What are the pros and cons of using a cold frame for propagation?
Do not require mains for heating. (could be situated on top of a hot bed!)
Relatively cheap to construct.
Need to be positioned south facing.
Too much heat/light can be an issue at certain times of year, so need to make sure lid is opened/removed.
Can only be used for certain types of propagation. Grey mould could be a problem if not ventilated.
What is a heated propagator and how is used for propagating vegetative cuttings?
A heated propagator provides heat at the base of the tray and is usually housed in a greenhouse with an electricity supply.
A temperature probe is placed in the growing medium in the container and the temperature can be adjusted depending on the plant growth need.
A lidded propagator can be used for softwood cuttings, leaf petiole, leaf bud cuttings. The heat at the base provides higher temperature for adventitious root growth at the base of the stem or petiole as well as an elevated ambient temperature.