Reproduction in Flowering Plants Flashcards
What are the 3 unique features of angiosperms life cycles?
- flowers
- double fertilization
- fruits
the reproductive shoots of sporophytes
flowers
What are some keys parts to flower formation?
- from shoot apical meristem to floral meristem
- from vegetative to reproductive growth
- stops primary growth
- flowers appear synchronously
- ABC hypothesis
What are some important things to know about the synchronicity of flowers?
- promotes out-breeding
- triggered by environmental and internal cues
- regulated by floral identity genes
explains the formation of floral organs through 3 classes of genes
ABC hypothesis
What are the 4 main organs of flowers?
1.) sepal
2.) petal
3.) stamen
4.) carpel
What are the female and male counterparts of flower organs?
male: stamen
female: carpel
What are the steps to the development of the embryo sac?
1.) megasporangium develops in the ovule
2. megasporangium undergoes meiosis
3.) 4 haploid megaspores are produced
4.) 1 megaspore survives and divides 3 times
5.) large cell is produced with 8 haploid nuclei
male gametophytes
pollen grains
What do pollen grains develop from?
haploid microspores
Where are haploid microspores produced from?
within the microsporangia of anthers
What do pollen consist of?
two-celled male gametophyte and spore wall
transfer of pollen from anther to stigma
pollination
What do pollen grains produce?
pollen tubes
When one sperm fertilizes the egg, _____ ____ is produced.
diploid zygote
When one sperm combines with polar nuclei, _____ ____-___ _____ is produced.
triploid food-storing endosperm
seed stops growing and slows metabolism
dormancy
What are some environmental cues to break dormancy?
- temperature changes
- lighting changes
- fire
- extended cold
- substantial rainfall
- chemical attack
extended time of dormancy full of ungerminated seeds
seed bank
How long can dormancy last?
days, decades, or longer
How can angiosperm produce?
sexually, asexually, or both
genetically variable offspring
sexual reproduction
genetic clones
asexual reproduction
What are the 3 mechanisms of asexual reproduction?
1.) fragmentation
2.) root system
3.) apomixis
separation of a parent plant into parts that develop into whole plants
fragmentation
asexual reproduction of seeds from a diploid cell
apomixis
What are the benefits of asexual reproduction?
- no need for a pollinator
- all of parent’s genes passed on intact
- strong progeny
What are the costs of asexual reproduction?
- clones are vulnerable to local extinction
What are the benefits of sexual reproduction?
- produces an enormous amount of seeds
- generates genetic variation
- facilitates dispersal
- seed dormancy is advantageous
What are the costs of sexual reproduction?
- only half of parental genes are passed on
- only a fraction of seedlings survive
What does self-fertilization do?
ensures every ovule develops into a seed
What is the downside to self-fertilization?
inbreeding
What are the 3 mechanisms to avoid selfing?
1.) dioecy
2.) incompatible carpels, stamens
3.) self-incompatibility genes
male or female flowers on different individuals
dioecy
recognition of self pollen triggers a block in pollen tube growth
self-incompatibility genes
