Gymnosperms
Lecturer: Asst. Prof. Dr. İsmail EKER
Tracheophytes
Seeded
Seedless
Ferns use
spores
Gymnosperms
“naked” or
exposed
seeds
Angiosperms
Flowers produce
fruit / enclosed
seeds
Evolution Of Land Plants
REMEMBER:
• Terrestrial plants evolved from a green
algal ancestor (Charophytes)
• The earliest land plants were nonvascular,
spore producers (bryophytes)
• Ferns were the 1st vascular, spore
producing plants
• Gymnosperms & angiosperms were the 1st
vascular, seed plants
Seeds vs spores
• Seeds are better than spores because spores
have a short lifetime.
• Spores are thinner walled and more
vulnerable to pathogens and damage.
Classification of Seed Plants
A. There are five phyla of extant seed plants:
1. Four of the phyla have naked ovules borne on
modified sporopylls. These are called
"gymnosperms" = “naked seed”.
Mostly Evergreen plants
2. In the remaining phylum (Anthophyta) the ovules
are enclosed within a protective structure called
an ovary (flower like reprodcutive structures).
Mostly Decidious plants
GYMNOSPERMS: Non-Flowering
Seed Producers
PHYLA OF GYMNOSPERMS
Cycadophyta (cycads)
Ginkophyta (maidenhair tree or Ginko)
Coniferophyta or Pinophyta (conifers)
Gnetophyta (Gnetophytes)
Phylum Coniferophyta
1. Most common gymnosperms are Conifers (about 70
genera & 630 species)
2. Conifers have leaves called needles or scales which
have a reduced surface area and thick waxy coat on
the needle to reduce water loss and prevents freezing.
3. Sporophylls arranged around a stem
4. Cones usually woody, sometimes soft & fleshy
5. Common members include the pine, fir, spruce, yew,
cypress, juniper, cedar and redwood.
6. Conifers are most common at the higher latitudes,
towards the poles
7. Conifers arose by 300 million years ago
Coniferophyta
•
•
•
•
Con- gr. cone, fer- L. bear.
Tracheids, but no vessel elements.
Sperm not motile.
Ovulate (female) & microsporangiate (staminate=male)
cones on same plant (Monoecius).
(Do not produce flowers or fruit)
Oldest living trees:
bristlecone pine
(Pinus longaeva)
!
up to 5000 years old!
White Mountains of
California
Tallest living trees: redwoods (Sequoia
sempervirens) may reach 112 m tall
cypress family Cupressaceae
!
coastal California and the southwestern
corner of coastal Oregon
Most massive trees: giant sequoia
(Sequoiadendron giganteum) may
reach diameters of 17 m
!
Sierra Nevada/California
Alternation of generations in
seedless and seed plants
Gymnosperms
(e.g., pine)
Key
Sporophyte
Megasporangia and
microsporangia are
found in separate
cones
Haploid
Diploid
Ovulate
cone
Megasporangium
Gametophytes
Pollen
cone
Megasporocyte
Meiosis
Meiosis
Meiosis produces
spores and begins
the haploid generation
Microsporocyte
Microsporangium
Egg
Megasporocytes (2n) are the cells within megasporangia
that
undergo meiosis to produce megaspores (n)
Microsporocytes (2n) are the cells within microsporangia
that undergo meiosis to produce microspores (n)
Fertilization
Gymnosperms
(e.g., pine)
Sporophyte
Haploid
Diploid
Ovulate
cone
Megasporangium
Gametophytes
Pollen
cone
Megasporocyte
Meiosis
Each megaspore develops
into a female gametophyte
Meiosis
Microsporocyte
Microsporangium
Pollen
Megaspore
Each microspore develops
into a male gametophyte (a
pollen grain)
Egg
A pollen grain gains access to
a female gametophyte through
a micropyle
Fertilization
Gymnosperms
(e.g., pine)
Sporophyte
Haploid
Diploid
Ovulate
cone
Megasporangium
Gametophytes
Pollen
cone
Megasporocyte
Meiosis
The female gametophyte
contains 2 or 3 (to 5)
archegonia, each with 1 egg cell
Meiosis
Microsporocyte
Microsporangium
Pollen
Megaspore
Two cells of the male
gametophyte are sperm
Archegonium
Egg nuclei
Sperm nuclei
Fertilization
Gymnosperms
(e.g., pine)
Fertilization (union
of 1 egg and 1
sperm) produces an
embryo
Key
Sporophyte
Haploid
Diploid
Ovulate
cone
Megasporangium
Gametophytes
Pollen
cone
Megasporocyte
Meiosis
Meiosis
Microsporocyte
Microsporangium
Pollen
Megaspore
Archegonium
Egg nuclei
Embryo
Sperm nuclei
Fertilization
Gymnosperms
(e.g., pine)
Key
Sporophyte
Haploid
Diploid
Ovulate
cone
Fertilization (union
of 1 egg and 1
sperm) produces an
embryo
Megasporangium
Gametophytes
Pollen
cone
Megasporocyte
Meiosis
Meiosis
Embryos develop
within seeds
Microsporocyte
Microsporangium
Seedling
Pollen
Seeds germinate
and embryos
become seedlings
Megaspore
Archegonium
Seed
Egg nuclei
Embryo
Sperm nuclei
Fertilization
Gymnosperm - heterospory
Independent and
dominant sporophyte
microspores
meiosis
2n
embryo
megaspores
n
megagametophyte
zygote
eggs
sperm
microgametophyte
Pine life cycle
Phylum Ginkgophyta
• 1 genus & 1 species - Ginkgo biloba
(the maidenhair tree)
• Yin- ch. silver, hing- ch. Apricot
• does not bear cones
• Tracheids, but no vessel elements
• Dioecious (Ovulate &
microsporangiate cones on separate
plants; fleshy-coated seeds)
• males are more commonly planted,
females produce seeds that have a
nasty odor
• pollination is by wind.
• multiflagellated swimming sperm
• Fan-shaped leaves (Veins nearly
Ancient
parallel with dichotomous branching)
group
unchanged in
200 million years
Female flowers (2 naked ovules on a peduncle) & seeds
Ginkgo biloba – a “living fossil”,
Ginkgo has not been found in the wild
and would probably be extinct but for
its cultivation in ancient Chinese and
Japanese gardens. Ancient trees (to
3,000 years old!) found in China &
Japan, in temple gardens and places
tended by people.
Male flowers
Phylum Cycadophyta
• ca. 11 genera (130 spp.)
• short shrubs, native to tropical regions
(look like palms)
• unbranched trunk (little wood)
• usually pinnately compound leaves
• loss of axillary branching
• dioecious: male and female plants
• male and female strobili (cones)
• motile, multiflagellate sperm
Look like a palm tree
but produce a cone
Cycas revoluta female
Cycas revoluta male
“naked” ovules
Ovule-bearing leaf
(megasporophyll) of cone
Strobilus of a “female” cycad
Phylum Gnetophyta
• 3 extant genera: Ephedra (65 spp.); Gnetum (28 spp.);
Welwitschia mirabilis
•have some angiosperm-like features (e.g. tracheids and vessel
elements; scalelike, leaflike, broad and leathery leaves; double
fertilization)
•Cladistic analyses support placement of the gnetales (or some
portion of them) as outgroups for the flowering plants
• With angiosperm-like broad leaves, but still retaining cones, the
Gnetophytes are another very close link to the Angiosperms.
• Sperm not motile.
• Pollen tube fuses with egg cell.
•Ovulate & microsporangiate cones compound and mostly borne
on separate plants (Dioceous).
Welwitschia
two huge leathery leaves
-a strange plant native to
deserts of Namibia, SW Africa
- Live up to 2000 years in
these extreme conditions!
- Only makes two leaves
throughout its life. It takes
water from sea mist
Gnetum
– leaves angiosperm-like
– vessels in the xylem
•considered an angiosperm characteristic
• tropical vines, trees, shrubs with opposite leaves
that look like angiosperms!
Ephedra
– Mormon tree
– common desert shrub
– reduced scale-like leaves
Significance of gymnosperms
•
•
•
•
•
•
•
•
•
Ecological importance:
Provide food and habitat for wildlife
Forests prevent soil erosion
Reduce greenhouse-effect gasses
Economic and commercial importance:
Lumber for wood, paper, etc.
Resins – wood, furniture, etc.
Ornamental plants (trees, landscaping)
Food – pine nuts (pesto-pine nut, bacil, garlic,
sold, cheese, olive oil)
Gymnosperms of Turkey
Coniferophyta
Abies (Köknar, Göknar)
• A. nordmanniana subsp. equitrojana (Kazdağı köknarı) E
• A. nordmanniana subsp. nordmanniana (Kafkas köknarı)- Doğu Karadeniz
• A. nordmanniana subsp. bornmulleriana (Uludağ köknarı)- Bursa, Bilecik, Batı ve
Orta Karadeniz E
• A. cilicica subsp. cilicica (Toros köknarı) – Toroslar
• A. cilicica subsp. isaurica (Toros köknarı) – Toroslar E
Picea (Ladin)
• Picea orientalis (Doğu ladini) - Karadeniz
Cedrus (Sedir)
• Cedrus libani (Lübnan sediri, Toros sediri) –Akdeniz (Elmalı, Amanoslar), Tokat, Afyon
Pinus (Çam)
• P. nigra subsp. pallasiana (Karaçam) – Widespread
• P. pinea (Fıstık çamı) - Akdeniz sahilleri, Maraş, Bursa, Trabzon, Çoruh, İzmir
• P. sylvestris (Sarıçam) – Karadeniz, Doğu ve İç Anadolu, İç Ege
• P. brutia (Kızılçam) – Ege ve Akdeniz, Zonguldak, Malatya
• P. halepensis (Halep çamı) – Adana/Kozan
Cupressus (Selvi, servi)
• Cupressus sempervirens (Adi servi, mezarlık servisi) – Toroslar
Juniperus (Ardıç)
• J. drupaceae (Eriksi ardıç) –
•
J. oxycedrus subsp. oxycedrus (Katran ardıcı) –
•
J. phoenica (Finike ardıcı) –
•
J. foetidissima (Kokar ardıç) –
•
•
•
•
•
J. sabina (Sabin ardıcı) –
J. excelsa (Boylu ardıç) –
J. communis subsp. hemisphaerica
J. communis subsp. Nana
J. oblonga () –
Taxus (Porsuk)
• Taxus baccata (Porsuk)
Gnetophyta
Ephedra (Deniz üzümü)
• E. campylopsida () –
• E. dictachya () –
• E. major () –
Encephalartos woodii (Cycadophyta) known only
from male plants
• !!!
– Endemic to South Africa
– But, extinct in the wild.
– All plants left are males in
gardens!
– Propagated by suckers (side
branches).
A very old bonsai
Ginkgo
Ginkgo in fall on Japanese street
• A-bomb resistant!
• This tree in Hiroshima,
Japan, was 1.1 km from
where the first Atomic
bomb was used in 1945.
What’s Wrong With This Picture?
Larix decidua
İt is a conifer (conebearer) but its not a
true “EVERGREEN”
Male Cone
Female Cone
deciduous coniferous tree