Cycads

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Cycads

• Heterosporous
• Megagametophyte in
• Megasporangium in
• Ovule on
• Megasporophyll
• Gymnosperm!

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A phylogeny of plants (excluding most of
Chlorophyta!)
taxa of various levels
Amborella
some extinct!
http//www.geol.umd.edu/tholtz/G331/images/embryo
phyta.gif
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http//mgonline.com/zamia01.jpg
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http//upload.wikimedia.org/wikipedia/commons/thum
b/9/90/Zamia_pumila_001.jpg/450px-Zamia_pumila_001
.jpg
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http//www.sci.muni.cz/bot_zahr/fotografie/sklenik
y/kapradiny/Zamia20floridana.jpg
http//site.voila.fr/MagicChris/Zamia/zamia_furfur
acea_JBrun.jpg
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http//www.ncarboretum.org/Horticulture/Bonsai/ima
ges/lo2620.jpg
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Lepidozamia hopei is one of the largest cycads
(20 m)
http//www.arf.net.au/images/lyall.jpg
http//www.plantapalm.com/Vce/cycadsof/queensland/
Lepidozamia_hopei_habitat_JL.JPG
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Coralloid root cross section with cyanobacterial
layer in cortex
http//protist.biology.washington.edu/Biol441/Lab
20Images/CIMG1393.jpg
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These above-ground roots are called coralloid
roots These are not for water and mineral uptake
but host an endosymbiosis
http//www.ucmp.berkeley.edu/seedplants/cycadophyt
a/coralloidroots.gif
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http//content.answers.com/main/content/wp/en-comm
ons/thumb/d/d8/250px-Cycas_circinalis.jpg
http//upload.wikimedia.org/wikipedia/commons/a/ae
/Microcycas_calocoma01.jpg
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http//www.floridata.com/wallpaper/jpg/Zamia_flori
dana800male.jpg
http//www.floridata.com/wallpaper/jpg/Zamia_flori
dana800female.jpg
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http//news.nationalgeographic.com/news/bigphotos/
images/071004-cycad-sex_big.jpg
http//waynesword.palomar.edu/images/csperm.gif
http//upload.wikimedia.org/wikipedia/en/thumb/e/e
9/Plant_sperm.png/180px-Plant_sperm.png
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Microspores contain an endosporic microgametophyte
http//www.cartage.org.lb/en/themes/sciences/Paleo
ntology/Paleozoology/Mesozoic/aquilap.jpg
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The tube cell of the microgametophyte emerges
through the microspore wall to penetrate tissue
leading up to the egg (mostly the nucellus).
http//virtual.yosemite.cc.ca.us/randerson/Lynn's
20Bioslides/76.jpg
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Megasporangiate cones have naked ovules on
Megasporophylls
A gymnosperm feature!
http//www.visitzululand.co.za/cycad20cone1.JPG
http//www.miamisunpost.com/200620Art20Basel/AB_
Cycad1.jpg
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Ovules grow and mature into seeds
http//www.cooloolacoastcare.org.au/Fireworks20as
sets/Macrozamia240.jpg
http//www.floridagardener.com/FLNatives/coontiese
eds2.jpg
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megagametophyte thallus
http//protist.biology.washington.edu/Biol441/Lab
20Images/CIMG1450.jpg
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Cycad seeds
http//www.plantapalm.com/Vce/horticulture/Zamiase
ed.jpg
http//www.plantapalm.com/Vce/images/cycadseed.JPG
Integument of ovule seed coat Megagametophyte
storage tissue Young sporophyte embryo with
suspensor
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Ginkgo biloba
http//www.cirrusimage.com/Trees/ginkgo_tree_med.j
pg
http//home.hiroshima-u.ac.jp/shoyaku/photo/Japan/
Hiroshima/Ginkgo.jpg
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Sporophyte first-year twig long shoot
http//www.landscapeproblemsolver.com/images/ginkg
o_tree.jpg
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Ginkgo biloba first-year leaf
http//www.thompsonsonsea.com/USERIMAGES/Ginkgo.jp
g
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Ginkgo biloba lateral branches are short-shoots
http//www.k5projects.com/plants/ginkgobiloba/gink
go1616.jpg
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http//www.cas.vanderbilt.edu/bioimages/biohires/g
/hgibi2-lfdevel10502.JPG
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Ginkgo biloba second-year or later leaf
http//www.cirrusimage.com/Mollusca/ginkgo_leaves_
med.jpg
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Ginkgo biloba stem cross-section
epidermis
2 phloem
2 xylem
cortex
periderm
1 xylem
cambium
pith
http//www.csupomona.edu/jcclark/classes/bot125/r
esource/graphics/g/gin_ginkgo_stem.jpg
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Confocal image of Ginkgo stem cross-section
(autofluorescence) Can you identify the cells and
organelles?
http//www.olympusfluoview.com/gallery/plants/imag
es/ginkgostemlarge.jpg
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Confocal image of Ginkgo stem cross-section
(autofluorescence) Can you identify the cells and
organelles? How old at harvest?
http//www.olympusfluoview.com/gallery/plants/imag
es/ginkgostemlarge1.jpg
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On Ginkgo biloba male trees, a strobilus will
shed endosporic microgametophytes (pollen) into
the air.
http//www.k5projects.com/plants/ginkgobiloba/gink
go3636c.gif
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http//www.life.uiuc.edu/ib/103/lab/tourimages/gin
kgo20pollen.jpg
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http//upload.wikimedia.org/wikipedia/commons/thum
b/e/e1/Ginkgo_pollen_cone_wm.jpg/800px-Ginkgo_poll
en_cone_wm.jpg
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Ginkgo microsporangiate strobilus ls
microsporophyll
cone axis
microspores
microsporangium
http//lh5.ggpht.com/Crystal.Canady/RimDCtu1jsI/AA
AAAAAAAYg/UNX2R9bKVWU/100_2418.jpg?imgmax512
Microspores are not shed. The cytoplasm in the
wall divides mitotically to produce an endosporic
microgametophyte which is shed.
cone axis
http//www.ucmp.berkeley.edu/IB181/VPL/CorCon/CorC
onP/CorCon24.jpeg
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Like cycads, Ginkgo is dioecious
http//www.biomedcentral.com/content/figures/1471-
2164-6-143-2.jpg
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On Ginkgo biloba female trees, a stalk produces
two naked ovules at its apex.
http//www.k5projects.com/plants/ginkgobiloba/gink
go101.gif
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Each female Ginkgo stalk has two naked ovules
(micropyle up)
http//www.huh.harvard.edu/research/mathews-lab/at
olHtmlSite/images/ginkgo-4.jpg
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When mature and ready for pollination, the
ovules micropyle secretes a pollination
droplet. Wind-borne pollen is trapped in the
droplet and is later pulled into the micropyle by
reabsorption of the liquid.
http//www.cas.vanderbilt.edu/bioimages/biohires/g
/hgibi2-cofemale-receptive50998.JPG
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http//www.sherwincarlquist.com/gnetales.html
http//tokyocinema.net/droplet.jpg
The sea in the seed January 2000
http//tokyocinema.net/E-ginkgo.htm
http//tokyocinema.net/gingkoC.jpg
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Ginkgo Ovule ls
micropyle integument megasporangium
nucellus megasporocyte or megaspore note
dichotomizing stalk for two ovules in highly
reduced megasporangiate strobilus
http//lh3.ggpht.com/Crystal.Canady/RimDENu1jtI/AA
AAAAAAAYo/wvVRPnAQEB4/100_2419.jpg?imgmax512
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micropyle
ovule integument
nucellus
M-gam
http//protist.biology.washington.edu/Biol441/Lab
20Images/CIMG1352.jpg
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egg
Megagametophyte thallus
http//protist.biology.washington.edu/Biol441/Lab
20Images/CIMG1360.jpg
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Maturing Ginkgo ovules
http//www.cas.vanderbilt.edu/bioimages/biohires/g
/hgibi2-cofemale-devel12309.JPG
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In autumn, the mature Ginkgo ovules fall to the
ground.
http//www.huh.harvard.edu/research/mathews-lab/at
olHtmlSite/images/ginkgo-1.jpg
43
Mature ovules have a fleshy integument producing
butyric acid.
http//www.cas.vanderbilt.edu/bioimages/biohires/g
/hgibi2-frcloseup15604.JPG
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The zygote forms an embryo by mitosis
http//protist.biology.washington.edu/Biol441/Lab
20Images/CIMG1365.jpg
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The embryo develops leaves, stem, and root
http//protist.biology.washington.edu/Biol441/Lab
20Images/CIMG1369.jpg
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An illustration and accompanying photographs show
how the agile Chinese orchid Holcoglossum
amesianum pollinates itself.
http//news.nationalgeographic.com/news/bigphotos/
images/060621-orchid-sex_big.jpg
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New Caledonia
Amborella trichopoda
http//images.livescience.com/images/060519_ambore
lla_04.jpg
http//www.flmnh.ufl.edu/flowerpower/fgpimages/amb
orella_fruit1.jpg
http//www.chlorischile.cl/cursoonline/guia3/ambor
ellaflorfem.jpg
http//www5e.biglobe.ne.jp/lycoris/amborella.jpg
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http//www.ucalgary.ca/laidlaw/amborella/amborell
a_seed.jpg
http//www.ucalgary.ca/laidlaw/amborella/amb_seed
_fleshy.jpg
http//www.ucalgary.ca/laidlaw/amborella/amborell
a_seedlng_3.jpg