1. Domain Eukarya Kingdom Plantae Phylum Anthophyta/Magnoliophyta
Flowering Plants
Domain Eukarya
Kingdom Plantae
Phylum Anthophyta/Magnoliophyta

2. Life Cycle of Flowering Plants
SYNGAMY
zygote
Sporophyte
Gametophyte
sporangium
sporocyte
spores
gametangia
gametes
germination
mitosis
differentiation 1N 2N
MEIOSIS
The flowering plant is a multicellular diploid sporophyte.
The sporophyte encloses the multicellular haploid gametophyte.
The life history is thus sporic (diplohaplontic).
The gametes are oogamous but the sperm lack flagellae.
Gender expression has moved from gametophyte to sporophyte.

3. Flower Organization-building a flower from bottom up
A flower is a short shoot (stem with leaves)
The stem is represented by the receptacle with very short internodes
The leaves appear in four whorls
stigma ™
carpel
gynoecium
flower
perfect
style
locule
ovary
anther
superior
stamen
pollen
ovule
filament
androecium
flower hypogynous
petal
corolla
receptacle
sepal
complete
perianth
calyx
pedicel

4. Microsporogenesis: Prophase I of Meiosis

5. Microsporogenesis: Late Prophase I of Meiosis

6. Microsporogenesis: Metaphase I of Meiosis

7. Microsporogenesis: Anaphase I of Meiosis

8. Microsporogenesis: Telophase I of Meiosis

9. Microsporogenesis: Metaphase II and Anaphase II of Meiosis

10. Microsporogenesis: Telophase II of Meiosis

11. Microsporogenesis: Meiosis complete (but prophase of mitosis)

12. Microsporogenesis: Completed, Separated Microspores (note prophase)

13. Pollen Grain: Mitosis Makes Endosporic Microgametophyte
Pollen Wall: Microspore Wall (allergenic?)
Tube Cell
Nucleus
Cytoplasm
Generative Cell
Nucleus
Cytoplasm
The tube cell digests a path from the stigma to the egg.
The generative cell follows the path to the egg, and divides to make two sperm cells. Both participate in syngamy.
Pollination: vector-assisted movement of the pollen grain from the anther to the stigma.

14. The tube cell germinates through the pollen wall.
Pollen Tube Growth
The tube cell germinates through the pollen wall.
The cell grows chemotropically toward the egg.
The pollen tube must find the ovule’s micropyle.
The generative cell slides along this tube.
It divides by mitosis to form two sperm cells.

15. Megasporogenesis: taking place inside the ovule inside the ovary.
megasporocyte
4 megaspores
meiosis I
meiosis II
3 disintegrate
functional
megaspore
mitotic divisions without cytokinesis
3 antipodals
megagametophyte
central cell
egg
cytokinesis
2 synergids

16. karyogamy! In Flowering Plants, syngamy is a double event: syngamy#2:
2 x 1N polar nuclei + 1N sperm
= 3N primary endosperm cell
sperm
nuclei
no miracle-gro, no compost!
1N egg + 1N sperm = 2N zygote
syngamy#1:
synergids
disintegrating
In this slide, plasmogamy has already occurred…but what part of syngamy has not occurred yet?
karyogamy!