Conifers
BIOL 1407
Seed Plants
• Vascular
Tissue
• Produce seeds
– Dispersal of
offspring
• Produce pollen
• Sperm transfer
without water
Seed Plants
• Sporophyte
dominant
• Gametophytes
– Greatly reduced
in size
– Dependent on
sporophyte
Seed Plants
• Heterosporous
– Megaspore
• Grows into
female
gametophyte 
eggs
– Microspore
• Grows into male
gametophyte 
sperm
–
–
Photo Credit for Ovulate Cone:
Dr. Stephen Bostic, ACC
Circled area: Ovule
Pollen Production
• Pollen cones have
microsporophylls
• Each
microsporophyll
has
microsporangia
•
Photo Credit for Immature Male Pine Cones:
Menchi, Wikimedia Commons
Pollen Production
• Meiosis occurs
within
microsporangia
 microspores
•
•
•
•
Photo Credit for Staminate Cone: Dr.
Stephen Bostic, ACC
Microsporangium circled in red
Microsporophyll at tip of yellow pointer
Microspores circled in pink
Pollen Production
• Microspores
grow into male
gametophytes
• Male
gametophyte =
pollen grain
Pollination
• Pollen is released
• Travels from male to
female
• Pollination occurs
when pollen grain
lands on female
• http://www.youtube.com/
watch?v=Bwl4g48-uIE
Pollen Germination
• After landing 
pollen coat
breaks open
• 1 cell produces
pollen tube
•
Photo Credit: Dr. David Byres,
Florida Community College at
Jacksonville
Pollen Germination
• A different cell
produces 2
sperm cells by
mitosis
• They will move
down pollen
tube as it grows
•
Photo Credit: Dr. David Byres,
Florida Community College at
Jacksonville
Pollen Germination
• Pollen tube
digests its way
through female
tissues to reach
the egg
Ovules
• Ovulate cones
have
megasporophylls
• Each
megasporophyll
has ovules
containing
megasporangia
•
Photo Credit for Immature Female
Ponderosa Pine Cones: Susan McDougall
@ USDA-NRCS PLANTS Database
Ovules
• Meiosis occurs
within
megasporangium
 forms 1
megaspore and 3
haploid nuclei
(degenerate)
•
•
•
Photo Credit: Dr. Stephen Bostic, ACC
Megasporangium circled in red
Megasporophyll at tip of yellow pointer
Ovules
• Megaspore
grows into
female
gametophyte
• Female
gametophyte
makes 1-2 eggs
by mitosis
Ovules
• Integuments
surround
female
gametophyte
• Micropyle 
lets pollen
reach female
gametophyte
Ovules  Seeds
• Integuments 
seed coat
• Female
gametophyte 
food supply
• Fertilized egg 
embryo
Seeds
• Dispersed by:
–
–
–
–
•
Wind
Animals
Water
Mechanical
Photo Credit for Pitch Pine Seeds:
Steve Hurst @ USDA-NRCS PLANTS
Database
Types of Seed Plants
• Gymnosperms
– Naked Seeds
– Not enclosed in
ovaries
– No fruits or
flowers
Types of Seed Plants
• Angiosperms
– Flowering Plants
– Seeds enclosed in
ovaries
– Fruits and flowers
Modern Gymnosperms
• Conifers
– Oldest living
plants
– Largest living
plants
– Widespread
– Reproductive
structure: Cones
Modern Gymnosperms
• Cycads
– Wiry leaves
– “Sago palms”
• Ginkgos
• Deciduous
trees
• One species
• Herbal
supplement
Modern Gymnosperms
• Gnetophytes
– Ephedra
(Mormon tea)
– Welwitschia
The End
Unless otherwise specified, all images in this presentation came from:
Campbell, et al. 2008. Biology, 8th ed. Pearson Benjamin Cummings.