Role Of Seeds In Propogation

Question 1

What is a seed?

Answer 1

A seed is the product of sexual reproduction
Formed from ovules as a result of fertilisation.
Method by which plants reproduce.

Question 2

State the benefits to a plant of sexual reproduction

Answer 2

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

Question 3

Describe the structure of a seed -Phaseolus vulgaris

Answer 3

Tests 
Cotyledon
Hilum
Plumule
Epicotyl
Hypocotyl 
Radicle
Micropyle

Question 4

Testa facts

Answer 4

Seed coat
For protection
Tough
May need damaging before germination - nicking, soaking, soil particles etc.

Question 5

Cotyledon

Answer 5

Seed leaf
Provides store of food for germinating seed
One seed leaf - monocot
Two seed leaves - dicot

Question 6

Hilum

Answer 6

Scar from where attached to ovary

Question 7

Plumule

Answer 7

Part of seed that forms first shoot

Question 8

Epicotyl

Answer 8

Connects cotyledon to plumule

Question 9

Hypocotyl

Answer 9

Connects cotyledon to radicle

Question 10

Radicle

Answer 10

Forms first root

Question 11

Micropyle

Answer 11

Small hole in testa where pollen tube entered ovule.

Can be where water enters for germination

Question 12

Horticultural benefits of propagation from seed

Answer 12

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.

Question 13

Limitations for propagation by seed

Answer 13

Some plants may not produce viable seed
Lack of uniformity
Difficult germination 
Some seeds don't store easily
Time to maturity

Question 14

Plant examples of usually propagated from seed

Answer 14

Daucus carota
Phaseolus vulgaris 
Solanum lycopersicon
Lobelia erinus 
Nigella damascena 
Lolium perenne

Question 15

Main horticultural uses of seed

Answer 15

Vegetables
Lawns
Annual decorative plants
Bedding plants

Question 16

What is a viable seed?

Answer 16

Has the potential for germination when conditions are right.

Contains living embryo

Question 17

Requirements for seed germination

Answer 17

Moisture
Oxygen
Temperature
Light/dark
Dormancy broken

Question 18

What is seed dormancy

Answer 18

When viable seed fails to germinate even when all germination conditions have been met.

Question 19

Describe changes in germinating seed

Answer 19

Takes in water 
Respiration rate increases
Breakdown of food store
Rapid cell division 
Splitting of seed coat/testa 
Emergence of radicle

Question 20

Example of epigeal germination

Answer 20

Cotyledon emerges above ground

Phaseolus vulgaris French bean

Question 21

Example of hypogeal germination

Answer 21

Cotyledons stay below the ground

Vicia faba

Question 22

What is meant by orthodox seed

Answer 22

Dry
Age slowly
Viable for many years possibly 100s

Question 23

What is meant by recalcitrant seed

Answer 23

Moist/fleshy 
Intolerant of drying out 
E.g. Quercus roba 
Aesculus hippocastanum 
Can't be kept for long

Question 24

Preparation and storage of Phaseolus vulgaris and nigella damascena

Answer 24

Collect ripe seed (when seed pods are brown)
Choose ones that are pest and disease free and true to type
Store pods and capsules in a warm place until they split
Clean the seed so is free from dust and debris (sieve)
Place in paper bag to be kept dry and cool. Lidded plastic box with silica gel in fridge.
Label and date

Question 25

Seed needing cool dry storage

Answer 25

Daucus carota 
Phaseolus vulgaris
Lobelia erinus
Nigella damascena
Lolium perenne

Question 26

Examples of seeds needing short term moist storage

Answer 26

Quercus robur

Aesculus hippocastanum

Question 27

Preparation of seed from fleshy fruit (Solanum lycopersicum)

Answer 27

Select fruit that is ripe, pest and disease free and true to type.
Cut in half and scoop out seeds into clean container
Wash the seeds to remove pulp that surrounds them
Strain seeds to remove pulp
Place seeds on piece of appear in warm area for 2-3 days until completely dry
Place seeds in paper bags 1-5 degrees
Label and date