Plants!
Reproduction Part 1 (lecture 15)
(Bryophytes & Pteridophytes)
Vegetative Reproduction
 Asexual Reproduction involving parts of a plant
 Cuttings
 Plant develops from stem, root, or leaf fragments
 Layering
 Formation of root off of a stem
 Grafting
 Aligning vascular cambium of 2 or more plant parts to join
them into one
 Tissue Culture
 Plant tissue cultivated and grown on nutrient media
Vegetative Reproduction
African Violet leaf cutting
Layering (raspberries)
Grafted Tree
V-graft (2 apple
varieties)
Plant tissue culture
Animal vs. Plant Life Cycle
Animal
Plant
diploid
multicellular
individual
2n
diploid
multicellular
sporophyte
mitosis
2n
zygote 2n
mitosis
meiosis
zygote 2n
fertilization
haploid
unicellular
gametes
1n
no multicellular
haploid
fertilization
meiosis
gametes
1n
spores
1n
mitosis
mitosis
haploid
multicellular
gametophyte
1n
alternation of generations
Alternation of Generations
 Alternation of Generations – A life cycle that
includes a multicellular diploid form
(sporophyte) and a multicellular haploid form
(gametophyte)
 Gametophyte - multicellular haploid form that
mitotically produces haploid gametes that unite and
grow into the sporophyte generation
 Sporophyte - multicellular diploid form that results
from a union of gametes and that meiotically
produces haploid spores that grow into the
gametophyte generation
Alternation of Generations
WHY, OH WHY
(does bio have to be so freaking confusing!)
?
 A “best of both worlds” idea
 Spore – with spores, only one parent
contributes to the genes in the offspring
 Beneficial if the parent is in a stable environment
because offspring will have all of the genes that
are successful in that area
 Gametes – both parents contribute genes
 Beneficial in a changing environment where
different traits may enhance survival of offspring
First Land Plants
haploid
 Bryophytes: mosses & liverworts
 non-vascular
 no water transport system
 no true roots
 swimming sperm
 flagellated sperm
 lifecycle dominated by
haploid gametophyte stage
 fuzzy moss plant you are
familiar with is haploid
 spores for reproduction
 haploid cells which sprout
to form gametophyte
diploid
Bryophyte Reproduction
 Gametangia (on gametophyte)
produce haploid gametes
 Antheridium – produces sperm
 Archegonium – produces egg
 Resulting zygote grows into a
diploid structure (sporophyte)
 In mosses the sporophyte is a stalk
 Spores from sporophyte disperse & develop into
haploid gametes
Gametophyte Dominant!
First Vascular Plants
 Pteridophytes: ferns
 vascular
 water transport system
 xylem, phloem, roots, leaves
 swimming sperm
 flagellated sperm
 life cycle dominated by
sporophyte stage
 leafy fern plant you are familiar
with is diploid
 fragile independent
gametophyte (prothallus)
 spores for reproduction
 haploid cells which sprout
to form gametophyte
haploid
diploid
Pteridophyte Reproduction
 Produce spores that form gametophytes
 Sori – sporangia clusters on the underside of
fern fronds
 Meiosis in sporangia forms spores
 Antheridia produce sperm and
archegonia produce eggs
 Sperm swim to meet eggs (fertilization
occurs at female reproductive structure)
& diploid sporophyte results
Sporophyte Dominant!
Alternation of Generations
 Fern gametophyte (1n)
 small haploid plant which produces gametes
 homospory: male & female on same plant
archegonia
antheridia
Fern Reproduction
haploid
Alternation of Generations
diploid
produces male
& female gametes
archegonia
antheridia
haploid
Pop Quiz!
1. The evolution of plants:
•a.started in aquatic environments.
•b.was marked by the development of specialized tissues
such as vascular tissue.
•c.led to the development of specialized organs.
•d.demonstrated a trend toward radiating into drier
environments.
•e.all of these
Pop Quiz!
2. All but which of the
following would be
associated with vascular
plants?
 a.root systems
 b.Bryophytes
 c.Angiosperms
 d.Gymnosperms
 e.shoot systems
3. Ferns are more
advanced than mosses
because mosses lack
which structure found in
ferns?
 a. spores
 b. cuticle
 c. xylem
 d. sporophytes
 e. pollen