R2104 1.3 Describe methods of harvesting and storing seeds Flashcards
What is an orthodox seed?
- Dry seed
- Can be stored for many years at cool temperatures
- Loses 90% of water as seed forms around the embryo
What is a recalcitrant seed?
- High in fats and oils
- Does not store well
Storing orthodox seed
- Best stored dry at fridge temperatures
- This maximises the viability of seed by slowing down their metabolism and slowing their rate of deterioration
- Store inside paper bags or envelopes which can be placed in plastic bags. Make sure they are labelled
Examples of orthodox seeds
require cool dry storage
- Daucus carota
- Phaseolus vulgaris
- Lobelia erinus
- Nigella damascena
- Lolium perenne
Preparation and storage of dry seed: Harvesting
Phaseolus vulgaris & Nigella damascena
- Collect seeds from healthy plants with desired characteristics
- Allow seeds to fully ripen before harvest - seed heads turn brown
- Harvest on a dry day. If it is wet and seed heads damp they are more prone to rotting
- Paper bags may be tied around seed heads to avoid dispersal of seeds
- Collect seeds in seed heads such as pods or capsules while still on stalks
- Leave in a warm dry place until completely dry
- Clean dust and debris (sieve) from seeds
Preparation and storage of dry seed: Extracting
Phaseolus vulgaris & Nigella damascena
- Larger seeds are easy to extract - open pods
- Smaller seeds may need to be separated from chaff. A fine meshed sieve can be used to gentle break up seed heads over a piece of paper. Seed falls thought sieve and chaff left behind
- Simple method to clean - place in shallow container and gently blow over the seeds to remove dust and chaff
Preparation and storage of dry seed: Storage
Phaseolus vulgaris & Nigella damascena
- Store seeds in paper packets or in an airtight container such as a plastic storage container with a lid
- Label with plant name and harvest date
- Scila gel can be used to remove excess moisture.
- Store in cool, dark dry conditions at 1-5- degrees C. Bottom of a fridge is ideal.
Examples of recalcitrant seeds
- Quercus robur
- Aesculus hippocastanum
Storage of recalcitrant seeds
- Best store in plastic bags of moist sand, peat substitute or fine vermiculite
- If recalcitrant seeds dry out they lose the viability
Stored seeds ability to germinate depends on?
- Moisture content of seed when put in store
- Temperature in store
- Length of time held in store
Preparation of fleshy fruits for storage - Solanum lycopersicum - Harvesting
- Fruit should be allowed to ripen -so that it slightly over ripe
Preparation of fleshy fruits for storage - Solanum lycopersicum - Maceration
- Wets seeds are coated with a gel that needs to be removed as it inhibits germination
- Needs a process of fermentation to remove gel and destroy disease causing organisms
- Cut fruits open and scoop out pulp and seeds,
- Place in a bowl of water. About half the volume of water as there is pulp and seed
- Ferment 3-4 days at 21 degrees C with occassional stirring. Do not leave too long as seeds may sprout. A thick skin will form on top.
Preparation of fleshy fruits for storage - Solanum lycopersicum - Seperation
- Dead seed will float to the top along with any remaining pulp
- Viable seed wil sink to the bottom
- Top layer of dead seeds and debris can be poured off carefully without disturbing the viable seeds
Preparation of fleshy fruits for storage - Solanum lycopersicum - Seperation
- Dead seed will float to the top along with any remaining pulp
- Viable seed wil sink to the bottom
- Top layer of dead seeds and debris can be poured off carefully without disturbing the viable seeds
Preparation of fleshy fruits for storage - Solanum lycopersicum - Cleaning
- Rinse seeds thoroughly in sieve under running water
- Should be carried out until all excess material has been removed
