Angiosperms Flashcards
What is the single phylum of angiosperm
anthophyta
What is included in angiosperms
seed plants
flowers
fruits
Flowers
specialized structure for sexual reproduction
How are flowers pollinated
animals (insects, mammals, birds) and wind
Pollinator has a large effect on the adaptations of the flower
color
shape
scent
Gymnosperms are primarily____pollinated
wind
Amorphophallus titanum
- largest unbranched inflorescence
- corpse flower
- only found in sumatra
Rafflesia schadenbegiana
- largest flower. 1 meter diameter, bloom lasts 5-6 days
- corpse flower
- Indonesia and malaysia
Flowers house the _____ generation
gametophyte
Modified stems bearing
modified leaves
Primordium
develops into a bud at the end of a stalk called the pedicel
pedicel
expands at the tip to form a receptacle, to which other parts attach
Flower parts are organized into circles called
Whorls
Outermost whorl
sepals
Second whorl
petals
Third whorl
stamens (androecium)
- pollen is the male gametophyte
- Each stamen has a pollen-bearing anther and a filament (stalk)
Innermost whorl
gynoecium
- consists of one or more carpels
- house the female gametophyte
The carpel
consists of an ovary at the base and a style leading up to a stigma where pollen is received
Sometimes carpel is referred to as ___
pistil
Embryo sac
female gametophyte
develops within an ovule contained within an ovary at the base of a stigma
Embryo sac
Daughter nuclei divide to produce
8 haploid nuclei in 2 groups of 4
What happens after the daughter nuclei divide
- 2 nuclei (1 from each group of 4) migrate toward center - ruction as polar nuclei - my fuse
- Cell closest to the micropyle becomes the egg
- 2 other cells are synergies
- Antipodals are the 3 cells at the other end - they have no function
Integuments become the
seed coat
The 8 haploid nuclei in 7 cells make up the
female gametophyte
also known as the embryo sac
The stamen
modified microsporophyll
male part of flower
Microsporangium - pollen sacs
Complete flower
has all 4 modified leaves
incomplete is missiong one or more
Perfect flowers
have both male and female parts
Monoecious plant
- has both male and female parts
- perfect flowers are monoecious
- but plant could have female flower ad male flowers
Dioicous plant
Each sporophyte produces either male or female gametophytes
Perfect flowers can’t
self pollinate
some plants have very high frequency of selfing
Mechanisms to prevent selfing
Gametophytic self incompatibility
Heterostyly
Sporophytic Self Incompatibility
Gametophytic self incompatability
Proteins prevent pollen tube from growing
Heterostyly
Stamens and Carpels are of different length
Pollen
Male gametophyte
Pollen structure influenced by dispersal methods
Exterior of pollen composed primarily of
Sporopollenin
A pollen grain that has landed on a stigma germinates and the pollen tube of the male gametophyte
grows down the ovary
Ovule is entered by a pore called the
micropyle
Double fertilization
occurs when the pollen tube discharges two sperm into the female gametophyte within an ovule
One sperm fertilizes the egg while the other combines with two nuclei in the central cell of the female gametophyte and initiates development of
food-storing endosperm
The endosperm
nourishes the developing embryo
Double fertilization continued
- one sperm unites with egg to form the diploid zygote - new sporophyte
- other sperm unites with the two polar nuclei to form the triploid endosperm - provides nutrients to embryo
Cotyledons
within a seed, the embryo consists of a root and one or two seed leaves called cotyledons
gymnosperms have 2-24 cotyledons
Hypogeal cotyledons
stay below ground and do not photosynthesize
Epigeal cotyledons
expand on germination and push off seed shell, photosynthesizing above ground