R2104 1.2 – 1.3 Seed Germination, Harvesting and Storing COPY Flashcards
What is a seed?
A seed is the product of sexual reproduction Formed from ovules as a result of fertilisation. Method by which plants reproduce.
State the benefits to a plant of sexual reproduction
Adaptation – survival of the fittest; strongest plants will thrive
Variety – mixing of characteristics gives chance of new and better plants
Survival – can survive harsh conditions as a seed
Volume
Testa facts
Seed coat For protection Tough May need damaging before germination - nicking, soaking, soil particles etc.
Cotyledon
Seed leaf Provides store of food for germinating seed One seed leaf - monocot Two seed leaves - dicot
Hilum
Scar from where attached to ovary
Plumule
Part of seed that forms first shoot
Epicotyl
Connects cotyledon to plumule
Hypocotyl
Connects cotyledon to radicle
Radicle
Forms first root
Micropyle
Small hole in testa where pollen tube entered ovule. Can be where water enters for germination
Horticultural benefits of propagation from seed
Produces variation from which new cultivars can be developed Only method for some species Can get large numbers from one plant Easily stored Can avoid virus transmission as guaranteed sources are available.
What are the limitations for propagation by seed?
Some plants may not produce viable seed
Lack of uniformity
Difficult germination
Some seeds don’t store easily
Time to maturity
What is a viable seed?
Has the potential for germination when conditions are right. Contains living embryo
What is seed dormancy?
When viable seed fails to germinate even when all germination conditions have been met.
Describe changes in germinating seed
Takes in water Respiration rate increases Breakdown of food store Rapid cell division Splitting of seed coat/testa Emergence of radicle