Angiosperm Life Cycle
Plant Reproduction Cheat Sheet
Meiosis
(2n)
-
-
Megasporangia  FEMALE
o Found in the Carpals/Pistils
(Flowers!)
o Contains cells called
megasporocytes (located within
ovules) that make ONE megaspore
Microsporangia  MALE
o Found in the Anthers (Stamen part
of Flower)
o Contains cells called
microsporocytes (located on
anthers) that make MANY
microspores
Cells within the sporangia are called
sporocytes
Mitosis
(n)
Mitosis
(2n)
Organs = Sporangia (have both male and
female)
-
Gametophyte
(n)
Spores
Sporophyte
Zygote
(2n)
Organs = Gametangium
Homosporous  makes one
kind of spore that can
develop into male or female
-
Heterosporous  Has two
separate types of spores
-
- Megaspores  Female
Spore; develops into
female gametophyte
- Microspores  Male
Spore; develops into
male gametophyte
Female Gametangium =
Archegonium  Produces
eggs
Male Gametangium =
Antheridia  produces
and releases sperm
Female Gametophyte = Embryo
Sac
Male Gametophyte = Pollen Grain
Mitosis
Fertilization
Gametes
(n)
Other Important Facts to Note:
Male Gametophyte = Pollen Grain
- Generative Cell  Gives rise to
2 sperm cells
- Tube Cell  Gives rise to the
pollen tube
Megasporocyte produces 4
megaspores but 3 die so only 1
survives. That ONE surviving
megaspore does 3 mitotic divisions
WITHOUT cytokinesis. This results in a
cell with 8 haploid nuclei:
- 1 egg
- 2 polar nuclei (forms
endosperm)
- 2 synergids (directs the pollen
tube)
- 3 antipodal cells (function
unknown)
Spores  Single-celled; can be
dormant; develops into the
gametophyte
Seed  multicellular; embryo (2n) and
endosperm (3n food source)
OVARY develops into FRUIT
OVULE develops into SEEDS
Double Fertilization 
- Function: To synchronize the development of the embryo with the development of the food
source
- Each Pollen Grain has 2 sperm cells:
o 1 sperm fertilizes the egg  2n zygote
o 1 sperm fertilizes the 2 polar nuclei  3n endosperm (food source for the seed!)