Plant reproduction Flashcards
Parts of flower
Carpel - ovary, style, stigma
Stamen- anther and filament
Polllination
The transfer of pollen from the anther to stigma of a flower from the species(self or cross)
Adaptations for wind pollination
Long filament
large feathery stigma
small petals not coloured brightly
Role of anther and stigma
release and trap pollen
Disadvantage of self pollination
susceptible to disease
no genetic variance
overcrowding
2 functions of sepal
protect the flower
photosynthesis
Megaspore into embryo sac
Megaspore mother cell divides by ,meiosis to form 4 haploid cells 3 degenerate remaining cell is embryo sac nucleus of this embryo sac divides by mitosis 3 times forming 8 haploid cells 5 degenerate remaining 3 gametes 2 form polar nuclei remaining forms an egg cell
Double fertilisation
Pollen grain lands on a stigma
Tube nucleus creates a tube from the stigma to the ovary. then it degenerates
Generative nucleus divides by mitosis
First nucleus fuses with the egg cell to produce a diploid zygote
2nd nucleus fuses with polar nuclei to form a triploid endosperm
Pollen grain development
Microspore mother cells located in pollen sac
They are diploid
Divide by meiosis to produce a group of 4 haploid cells called a tetrad
Each tetrad breaks up to form 4 separate haploid pollen grains
Pollen grains divide by mitosis producing 2 haploid nuclei
Vegatative propogation
form of asexual reproduction
Advantage and disadvantage of vegatative propogation
Rapid growth
Competition with parent
Methods of natural vegetative propagation
Stem-Rhizome
Bud-onion
Root-tap roots(carrot)
Leaf-Lily
Example of artificial vegetative propagation
Layerings and cuttings
Benefit to artificial vegetative propagation
Rapid and more reliable
