plant reproduction Flashcards
describe the stages of the life cycle of plants**
gametophyte stage:1n
sporophyte stage: 2n
describe the reproductive structures of plants**
four whorls:
1. calyx: all sepals
2. corolla: all petals
3. androecium: male reproductive part
4. gynoecium: female reproductive part
complete vs incomplete flowers
complete: all 4 whorls
incomplete: at least one part is missing
reproductive structures
androecium
-filament holding anther which contains pollen inside
gynoecium
- carpel
stigma, style and ovary
eggs are inside the ovules
perfect flowers contain both androecium and gynoecium
monoecious
both male and female flowers are on the same plant
dioecious
male and female flowers are on separate plants
superior flower
the ovary is above other flower parts
inferior flower
the ovary is below other flower parts
male gametophyte: the pollen grain
develops inside the anther
mature pollen grains contain two cells
- pollen tube cell: forms the pollen tube after pollination
-generative cell: divides during pollination into two sperm cells
female gametophyte: the embryo sac
a diploid central cell contains 2 polar nuclei
the egg cell is the female gamete
the gametophyte is surrounded by integuments which will later develop and become the seed coat
pollination
the placement or transfer of pollen from the anther to the stigma of the same flower or another flower
what are the types of pollination
self-pollination: pollen is from the same flower, or another flower on the same plant
cross-pollination: pollen is from the anther of one flower to the stigma of another flower on a different individual of the same species
- greater genetic diversity
pollinators
insects, birds, wind, water
double fertilization
one sperm fertilizes the egg to form the 2n zygote, that will develop and become the embryo
the other sperm fertilizes the central cell to form the 3n endosperm
development of the seed
embryonic development is suspended after some time- growth is resumed only when the seed germinates
developing seedlings will rely on the food reserves stored in the endosperm and cotyledons until the first set of leaves begin photosynthesis
development of the fruit
after fertilization, the ovary of the flower usually develops into the fruit
not all fruits are sweet and edible
the fruit encloses the seeds and the developing embryo
simple fruits
form from a flower with one carpel
aggregate fruit
form from flower with many ovaries
multiple fruits
made up of multiple flowers
accessory fruits:
develop from tissue other than the ovary
fruit and seed dispersal
fruits have one purpose: seed dispersal
go far from the mother to find favorable and less competitive conditions
fruits and seeds are dispersed by various means
wind, water, and animals
asexual reproduction
many plants are able to propagate
with no need to produce flowers, attract pollinators, or find means to for seed dispersal.
produces plants that are genetically identical to the parent
asexual reproduction- artificial
grafting: favorable stem traits and favorable roots
cutting: portion of the stem containing nodes and internodes is placed in moist soil and allowed to root
layering: stem attached to the plant is bent and covered with soil
micropropagation: AKA plant tissue culture; propagate plants in sterile laboratory conditions
