LO 4.1 - Principles of seed sowing by describing the following Flashcards
- Seed types – berry, nut, samara - Methods of seed collection - Methods of seed extraction and cleaning
Review
Seed
Principles of propagation by Seed
Seed
* The main method of reproduction in nature
* Most efficient method of propagation for cultivated crops
* Can be mechanised using systems specially developed - Sowing - Seed bed formation - Spraying - Undercutting and transplantation
Principles of propagation by Seed
Question
What are Advantages of Seed?
Principles of propagation by Seed
Seed Advantages
* Cheap method of production
* Can raise large quantities of plants
* Less risk of transmitting virus
* Establish faster after transplantation than vegetatively produced plants
* Less regulations involved in export / import
Principles of propagation by Seed
Question
What are Disadvantages of Seed?
Principles of propagation by Seed
Seed Disadvantages
* Can generally only be used for propagation of species as » varieties etc. don’t come true to type
* Dormancy difficulties, double dormancy etc. » Crataegus monogyna
* Lack of viability with some species » *Fagus sylvatica *
* Genetic variations generally poorer than garden varieties etc.
* Sex of off-spring may not be known » Ilex aquifolium
Principles of propagation by Seed
Question
What is Seed Provenance?
Principles of propagation by Seed
Seed Provenance is the geographical origin of seed
Provenance directly affects characteristics .
* Pest and disease susceptibility.
* Drought/Cold resistance.
* Time of flushing of growth.
* Onset of dormancy.
* Time of flower set.
Principles of propagation by Seed
Question
What is the importance of Seed Provenance?
Principles of propagation by Seed
Importance of Seed Provenance
* Knowledge of provenance is important in selecting plant material for a particular location/site - Adaptability to a particular location
Principles of propagation by Seed
Question
What is Seed Dormancy?
Principles of propagation by Seed
Seed Dormancy
* A period of sleep or rest for a seed
* Natural defence mechanism to ensure seedling survival - Adverse weather conditions - Fire - Flood
Principles of propagation by Seed
Question
Seed Dormancy can be attributed to physical limitations.
What are they?
3 points
Principles of propagation by Seed
Seed Dormancy - Physical Limitations.
Dormancy attributed to physical limitations on germinations.
* Prevents uptake of water.
* Restricts exchange of gases.
* Limits embryo expansion
Principles of propagation by Seed
Question
Seed Dormancy can be attributed to Immaturity embryo.
What does that mean?
Principles of propagation by Seed
Seed Dormancy - Immaturity.
* Sometimes a seed may be immature but exists in berry form, eg. Viscum album ‘Mistle toe’
Principles of propagation by Seed
Question
Seed Dormancy can be caused by Inhibitors to germination.
Explain…
Principles of propagation by Seed
Seed Dormancy - Inhibitors
* Sometimes berries have the ability to produce an inhibitor within the fruit that prevents it from germinating until a period of time has passed or until it has passed through the gut of an animal. So seed doesn’t germinate till the inhibitor is cleaned off.
Principles of propagation by Seed
Info Graphic
Inhibitors to Germination - Berry
Principles of propagation by Seed
Seed Dormancy - Inhibitors
Time for a video?
LO4 Prepare seed for sowing
Principles of propagation by Seed
Question
What is Seed Coat Dormancy?
Principles of propagation by Seed
Developments of hard seed coat.
* Limits germination.
* Broken down over time - In soil - By animals.
Impermeable seed coat.
* Caused by water repellent ability of seed.
Principles of propagation by Seed
Question
What is the significance of the size of seeds?
Principles of propagation by Seed
Large seed are produced in small numbers
* Germinate well
* Establish well
* E.g. Chestnut, Hazelnut, Acorn
Dust or small seed produced in large numbers
* Don’t germinate as well
* Don’t establish and survive as well
* E.g. Rhododendron, Lobelia etc.
Principles of propagation by Seed
Question
What is the significance of the size of seeds?
Principles of propagation by Seed
Large seed are produced in small numbers
* Germinate well
* Establish well
* E.g. Chestnut, Hazelnut, Acorn
Dust or small seed produced in large numbers
* Don’t germinate as well
* Don’t establish and survive as well
* E.g. Rhododendron, Lobelia etc.
Principles of propagation by Seed
