Sexual Plant Propagation Flashcards
what are the 2 methods of plant propagation?
- sexual: exchange genetic info ie seeds
2. asexual: cloning, no exchange genetic info
what method is used for cultivated plants ?
asexual
-do not come ‘true’ from seed, vary genetic info
what are 4 advantages of sexual propagation?
- only way to produce NEW varieties or cultivars
- cheapest and easiest way to produce large # plants
- avoid certain diseases
- may be only way to propagate certain species
t of r sexual propagation is the only was to reproduce new varieties
false, only way to produce new varieties
what is the purpose of a flower?
- sex
- male + female sex cells = seeds
- reproduction
what are usually grown from seed?
- annual and biennial veg. and flowers
- lawn grasses
- inderstock for grafting
t or f perennials grown from seed may take more than one season to flower
true
t or f reproduction of ‘Species’ must be from seed
true
t or f reproduction of ‘Cultivars’ from seed
false, vegetative
where do new plants come from?
- someone makes them or someone finds them
how are new plants ‘made’
- breeders move pollen from one plant to another, sowing resulting seed and waiting to see what develops
- select plant with specific traits in hope combining
- deliberately cause mutation then crossing and waiting
what is a hybrid plant
- cross between 2 plants of general varieties, cultivars, species, genera
- offspring can exhibit best traits of both parents are unexpected attribute may appear
describe how new plants can be found
- branch can appear with leaves/ flowers differing from rest of plant ( called ‘Sport’)
- one seedling stand out from others
- appear in garden as result of natural crossing by wind or pollinators
t or f the seeds of hybrid cultivars can be utilized for reproduction
false
what plant make good seed for propagation
- self pollinated, non hybrid purebred annual veg seeds
what are heirloom varieties
- great grandparents of modern cultivars
what 3 parts are a seed made up of
- outer protective coat
- food supply under seed coat (endosperm)
- embryo of young plant
what are factors that affect germination
- water
- light
- oxygen
- heat
what is essential for first phase of germination
WATER
- penetrates seed coat and causes endosperm to swell
- seed coat softens, splits as endosperm swells
- water dissolves nutrients in endosperms –> available to embryo so growth occurs
what does water additionally do in desert annuals
- leach away germination inhibitor abscisic acid
what is the ideal germination medium?
- moist, not wet or dry
what factor do temperate- climate angiosperms need before the germinate?
- prolonged cold period
why is a cold period soemtimes necessary for germination to occur?
- break down ABA until not enough left to prevent germination when conditions become favourable
why is germination inhibitors found within seed?
-prevent germination during unseasonable warm spell in autumn
how does the ideal germination temperature achieved?
- heating cables placed under germination containers
what are 2 treatments to break dormancy/ germination inhibitors
- scarification - in nature seed pass through digestive tract, stepped on ect
- stratification: mimics northern winter
what are 2 methods used for scarification
- mechanical and hot water
why do seeds appear to sprout sporadically?
- must mimic ideal germination conditions
- defence mechanism; if first flush seedlings killed from adverse weather, more will come in their place
true or false a seed grown selection is termed a ‘strain’ to indicate similar but not identical genetics were used
true
why use vegetative propagation
- poor seed production
- poor seed viability
- no seed viability- sterile plant
- only 1 specimen avail.
- preserve genetic info
