Plant Morph Test 2

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1

shoot

The aboveground portions, such as the stem and leaves, of a vascular plant.

2

phytomeres

A succession of repeated developmental units, consisting of a node with its attached leaf (or leaves), the internode below the leaf (or leaves), and the bud (or buds) at the base of the internode.

3

apical meristem

The meristem at the tip of the root or shoot in a vascular plant.

4

tunica-corpus

The organization of the shoot apex of most angiosperms and a few gymnosperms, consisting of one or more peripheral layers of cells (the tunica layers) and an interior (the corpus).

The tunica layers undergo surface growth (by anticlinal divisions), and the corpus undergoes volume growth (by divisions in all planes).

5

pith

The ground tissue occupying the center of the stem or root within the vascular cylinder; usually consists of parenchyma.

6

interfasicular region

or pith ray

Tissue region between vascular bundles in a stem.

7

herbaceous

Referring to nonwoody plants.

8

leaf trace

That part of a vascular bundle extending from the base of the leaf to its connection with a vascular bundle in the stem.

a vascular bundle that diverges from the axial bundles in the stem and enters a leaf.

9

leaf trace gap

In seed plants, region of parenchyma tissue in the primary vascular cylinder of a stem above the point of departure of the leaf trace or traces.

break in the vascular tissue of a stem above the point of attachment of a leaf trace

10

stem bundle

Vascular bundle belonging to the stem.

11

sympodium

A stem bundle and its associated leaf traces.

12

phyllotaxis

The arrangement of leaves on a stem. Also called phyllotaxy.

13

blade

The broad, expanded part of a leaf; the lamina.

14

petiole

The stalk of a leaf.

15

stipule

An appendage, often leaflike, on either side of the basal part of a leaf, or encircling the stem, in many kinds of flowering plants.

16

sessile

Attached directly by the base; referring to a leaf lacking a petiole or to a flower or fruit lacking a pedicel.

17

sheath

(1) The base of a leaf that wraps around the stem, as in grasses;

(2) a tissue layer surrounding another tissue, such as a bundle sheath.

18

rachis

The main axis of a spike; in ferns, the axis of a leaf (frond), from which the pinnae arise; in compound leaves, the extension of the petiole corresponding to the midrib of an entire leaf.

19

mesophyte

A plant that requires an environment that is neither too wet nor too dry.

20

hydrophyte

A plant that depends on an abundant supply of moisture or that grows wholly or partly submerged in water.

21

xerophyte

A plant that has adapted to arid habitats.

22

mesophyll

The ground tissue (parenchyma) of a leaf, located between the layers of epidermis; mesophyll cells generally contain chloroplasts.

23

palisade parenchyma

A leaf tissue composed of columnar chloroplast-bearing parenchyma cells with their long axes at right angles to the leaf surface.

24

spongy parenchyma

A leaf tissue composed of loosely arranged, chloroplast- bearing cells.

25

vein

A vascular bundle forming part of the framework of the conducting and supporting tissue of a leaf or other expanded organ.

26

netted venation

The arrangement of veins in the leaf blade that resembles a net; characteristic of the leaves of all angiosperms except for monocots. Also called reticulate venation.

27

parallel venation

The pattern of venation in which the principal veins of the leaf are parallel or nearly so; characteristic of monocots.

28

minor veins

The small leaf vascular bundles, located in the mesophyll and enclosed by a bundle sheath; involved in distribution of the transpiration stream and uptake of the products of photosynthesis.

29

major veins

The larger leaf vascular bundles, which are associated with ribs; they are largely involved in the transport of substances into and out of the leaf.

30

bundle sheath

Layer or layers of cells surrounding a vascular bundle; may consist of parenchyma or sclerenchyma cells, or both.

31

bulliform cells

Large epidermal cells present in longitudinal rows in grass leaves; believed to be involved in the mechanism of rolling and unrolling or folding and unfolding of the leaves. Also called motor cells.

32

founder cells

The group of cells from which leaf primordia and root primordia are initiated.

33

abscission

The dropping off of leaves, flowers, fruits, or other plant parts, usually following the formation of an abscission zone.

34

abscission zone

The area at the base of a leaf, flower, fruit, or other plant part containing tissues that play a role in the separation of the plant part from the plant body.

35

leaf scar

A scar left on a twig when a leaf falls.

36

transition region

The region in the primary plant body showing transitional characteristics between structures of root and shoot.

37

homeotic mutation

A mutation that changes organ identity so that the wrong structures appear in the wrong place or at the wrong time.

38

homeotic genes

Genes affecting floral organ identity.

39

tendrils

A modified leaf or part of a leaf or a modified stem forming a slender, coiling structure that aids in support of the plant’s stems;

found only in some angiosperms.

40

cladophyll

A branch resembling a foliage leaf.

41

tuber

An enlarged, short, fleshy underground stem, such as that of the potato.

42

stolon

A stem that grows horizontally along the ground surface and may form roots, such as the runners of a strawberry plant.

Also called a runner.

43

rhizome

A more or less horizontal underground stem.

44

bulb

A short underground stem covered by enlarged and fleshy leaf bases containing stored food.

45

corm

A thickened underground stem, upright in position, in which food is accumulated, usually in the form of starch.

46

Basic Function of Shoot System

structural support, growth through increase in diameter (girth) and elongation, transport of fluids between the roots and the leaves.

47

stems

the part of the plant from which shoots and buds arise

48

Examples of Stems

card image

1. Dogwood, 2. oak, 3. sycamore, 4. sweetgum, 5. honeylocust

49

Climbing stem

card image

adaptation to reach sun without strong stem built

50

Cellular arrangements and tissue organization

card image

parenchyma, collenchyma, sclerenchyma, xylem, companion cell, sieve tube, vascular cambium, cells of ground tissue, epidermal cell.

51

Anti-clinal cell division

card image

vertical to surface

Example: tunica

52

Peri-clinal cell division

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parallel to surface

example: corpus (both anti and peri)

53

Tunia - Layer 1

card image

forms Epidermis

54

Tunica - Layer 2

card image

generates cell layers beneath epidermis

55

Corpus

card image

pith, cortex and vascular tissue

56

Terminal buds form...

leaves and flowers

57

Lateral buds form

leaves

58

Three types of stem anatomy in seed plants

(a) Conifers, some dicots

(b) most dicots

(c) monocots

59

Cross section Tilia Americana

card image

Tilia Americana

60

Primary Xylem

1. Proto-xylem

initial primary xylem differentiate first

61

Primary Xylem

2. Meta-Xylem

Primary xylem differentiate later (after protoxylem)

62

Modified Stems - Rhizome

underground root-like stem (iris, ginger)

63

modfied stems - tuber

fleshy underground stem (potatoe, yam)

64

Modified Stems - bulb

underground stem with many scales (onion, garlic)

65

Modified Stems - Corm

underground bulb-like structure, no scales gladiolus

66

Modified Stems - Stolon

above ground "runners" (strawberry)

67

Modified Stems - Thorn

above ground stems (rose)

68

Modified Stems - Cladophylls

Leaf-like stems contain nodes, flowers, leaces,

Examples: rucus asparagus, smilax, and various cactus

69

Monocots

- 1 cotyledon

- floral part in threes

- parallel leaf veins

-pollen grain has one pore or furrow

- vascular bundles throughout stem's ground tissue

70

Dicots

- 2 cotyledon

- floral parts in 4s or 5s

- netlike leaf veins

-pollen grain has three pores or furrows

- vascular bundles arranged in a ring

71

Monocot Stem

Vascular Bundles: Phloem

1. sieve tube members

2. sieve plates

3. companion cells

72

Monocot Stem

Vascular Bundles: Xylem

1. vessels

- usually 2 per bundle

- make up the eyes of the bundle

2. air space

3. tracheids

4. parenchyma

73

Sun leaves

smaller, thicker, more mesophyll

74

Shade Leaves

larger, thinner, fewer mesophyll

75

Specializations for extreme environments

abscission (death), carnivory, hydrophytes (aquatic plants), xerophytes (desert plants)

76

Carnivory

leaf is modified to trap insects for trace nutrients

77

Phyllotaxy

arrangement of leaves on stem

78

Phyllotaxy - alternate

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one leaf per node

79

Phyllotaxy - opposite

card image

two leaves at same node

80

Phyllotaxy - whorled

card image

3/+ leaves at the same node

81

Parts of the Leaf

blade, petiole, stipules (small-leaf-like)

82

Leaf Shape: simple

one blade

83

Leaf shape: compound

several blades

i. pinnate - ash walnut, hickory

ii. palmate - buckeye

84

specialized epidermal cells

buliform cells, trichomes glands

85

Epidermis

abaxial and adaxial, stomata, guard cells, cuticle, specialized epidermal cells (bullifom cells, trichomes, glands)

86

Mesophyll - "middle of the leaf"

Palisade Mesophyll

located on adaxial side

contain >80% of plastids

controls light intensity and damage

87

Spongy Mesophyll

spongy appearance because of air spaces, allowing free gas flow

primary site for photosynthesis

88

Vascular Bundles (veins)

xylem and phloem

often enclosed by bundle sheaths of sclerenchyma fibers

89

Hydrophytes

large amount of water

water lily - floats in water, large air gaps

90

Xerophytes

adapted to arid climates

Nerium oleander - thick cuticle, restricted stomata, and trichomes

91

mesophytes

not wet or dry

92

What opens Stomata

daytime, K+ in Guard cells, H2O in Guard cells

93

Modified leaves - needle

pine, fir

94

Modified Leaves - Bract

reduced leaf

holding a flower

example: poinsettia, dogwood

95

Modified Leaves - storage

leaf modified for food storage

examples: onion, tulip, lily

96

Modified Leaves - succulent

thick, fleshy modified for water sotrage

examples: crassula, portulaca, aloe

97

Modified Leaves - Tendril

slender, twining modified leaf or stem for support

example: grape, cucumber

98

Modified Leaves - spine

cactus, locust, holly

99

Modified Leaves - trichome or hair

geranium, tomato, begonia

100

Leaves change color in fall due to

changes in length of daylight and temp

leaves stop photosynthesis

chlorophyll breaks down, green disappears, and yellow and orange colors become visible and give the leaves part of their fall splendor.

101

systematics

Scientific study of the kinds and diversity of organisms and of the relationships between them.

taxonomy + phylogeny

102

taxonomy

The science of the classification of organisms.

biological diversity

103

specific epithet

The second part of a species name; for example, mays of Zea mays (maize).

104

category

In a hierarchical classification system, the level at which a particular group is ranked.

105

taxon

General term for any one of the taxonomic categories, such as species, class, order, or phylum.

106

phylogeny

evolutionary history

Evolutionary relationships among organisms; the developmental history of a group of organisms.

107

clade

A monophyletic group, made up of an ancestor and all of its descendants.

108

analogous

Applied to structures similar in function but different in evolutionary origin, such as the phyllodes of an Australian Acacia and the leaves of an oak.

109

convergent evolution

The independent development of similar structures in organisms that are not directly related; often found in organisms living in similar environments.

110

cladistics

A system of arranging organisms following an analysis of their primitive and advanced features so that their phylogenetic relationships are accurately reflected.

111

synapomorphies

Character states (two or more forms of a character) that arose in the common ancestor of a group and are present in all of its members.

112

outgroup

In a cladogram, a species or group of species that does not exhibit one or more shared derived characters found in the group under study, the ingroup.

113

cladogram

A line diagram that branches repeatedly and suggests phylogenetic relationships among organisms.

branching diagram represent best estimate of phylogeny

evolution of individual species

114

Eukarya

The phylogenetic domain containing all eukaryotic organisms.

115

alternation of generations

A reproductive cycle in which a haploid (n) phase, the gametophyte, produces gametes, which fuse in pairs to form a zygote, which then germinates to produce a diploid (2n) phase, the sporophyte. Spores produced by meiotic division in the sporophyte give rise to new gametophytes, completing the cycle.

116

gametophyte

In plants that have an alternation of generations, the haploid (n), gamete-producing generation, or phase.

117

sporophyte

The spore-producing, diploid (2n) phase in a life cycle characterized by alternation of generations.

118

isomorphic

Identical in form.

119

heteromorphic

Describing a life history in which the haploid and diploid generations are dissimilar in form.

120

evolution

The derivation of progressively better-adapted forms of life from simple ancestors; Darwin proposed that natural selection is the principal mechanism by which evolution takes place.

- all living things on earth today are the descendants with modifications - of earlier species.

121

Organic evolution

genetic changes in populations through many generations

122

Adaptation

A peculiarity of structure, physiology, or behavior that aids in fitting an organism to its environment.

over the course of time, species modify their phenotypes in ways that permit them to succeed In their environment.

123

Speciation

The origin of new species in evolution.

over the course of time, # of species multiplies,

a single species can give rise to 2+ descendant species.

124

Natural selection

The differential reproduction of genotypes based on their genetic constitution.

- Living things produce more offspring than finite resources face a constant struggle for existence.

- individuals in a population vary in their phenotypes. Some of this variation inheritable

- Those best adapted to conditions are most likely to survive and reproduce themselves ("survival of the fittest").

125

Measure of Fitness

reproductive success

those individuals who leave the largest # of matrue offspring = the fittest.

can be achieved by - survival or mortality selection, mating success or sexual selection , family size.

126

Phylogenetic Tree

Family Tree

show the evolutionary relationships exist among organisms

127

Homologies

characteristics shared by different organisms

128

analogous feature

Applied to structures similar in function but different in evolutionary origin, such as the phyllodes of an Australian Acacia and the leaves of an oak.

have common function

129

plankton

Free-floating, mostly microscopic, aquatic organisms.

130

phytoplankton

Aquatic, free- floating, microscopic, photosynthetic organisms.

131

zooplankton

A collective term for the nonphotosynthetic organisms present in plankton.

132

agar

A gelatinous substance derived from certain red algae; used as a solidifying agent in the preparation of nutrient media for the growth of microorganisms.

133

eyespot

A small, pigmented structure in flagellated unicellular organisms that is sensitive to light. Also called a stigma.

134

stigma

(1) The region of a carpel that serves as a receptive surface for pollen grains and on which they germinate;

(2) a light-sensitive, pigmented structure

135

contractile vacuole

A clear, fluid-filled vacuole in some groups of protists that takes up water within the cell and then contracts, expelling its contents from the cell.

136

paramylon

The storage molecule of euglenoids.

137

pyrenoid

A differentiated region of the chloroplast that is a center of starch formation in green algae and hornworts.

138

fucoxanthin

A brownish carotenoid found in brown algae and chrysophytes.

139

heterokonts (or stramenopiles)

Organisms with one long, ornamented (tinsel) flagellum and one shorter, smooth (whiplash) flagellum; include oomycetes, chrysophytes, diatoms, brown algae, and certain other groups.

140

frustule

The two-part cell wall of a diatom, made up of polymerized, opaline silica (SiO2 • nH2O) and consisting of overlapping halves.

141

chrysolaminarin

The storage product of the chrysophytes and diatoms.

142

kelp

A common name for any of the larger members of the order Laminariales of the brown algae.

143

thallus

A type of body that is not differentiated into root, stem, or leaf.

body portion of an algae

144

laminarin

One of the principal storage products of the brown algae; a polymer of glucose.

145

blade

The broad, expanded part of a leaf; the lamina.

146

mannitol

One of the storage molecules of the brown algae; an alcohol.

147

carpogonium

In red algae, the female gametangium.

148

trichogyne

In the red algae and certain ascomycetes and Basidiomycota, a receptive protuberance of the female gametangium for the conveyance of spermatia.

149

carpospores

In red algae, the single diploid protoplast found within a carposporangium.

150

tetrasporophyte

In certain red algae, a diploid individual that produces tetrasporangia.

151

phycoplast

A system of microtubules that develops between the two daughter nuclei, parallel to the plane of cell division. Phycoplasts occur only in green algae of the class Chlorophyceae.

152

phragmoplast

The layer of cytoplasm that forms across the cell where the nucleus becomes located and divides.

153

sporopollenin

The tough substance of which the exine, or outer wall, of spores and pollen grains is composed; a cyclic alcohol highly resistant to decay.

154

oogonium

A unicellular female sex organ that contains one or several eggs.

155

oospore

The thick-walled zygote characteristic of the oomycetes.

156

homothallic

Describing a species in which the individuals are self-fertile.

157

heterothallic

Describing a species with haploid individuals that are self-sterile or self-incompatible; two compatible strains or individuals are required for sexual reproduction.

158

plasmodium

Stage in the life cycle of myxomycetes (plasmodial slime molds); a multinucleate mass of protoplasm surrounded by a membrane.

159

pseudoplasmodium

A multicellular mass of individual amoeboid cells, representing the aggregate phase in the cellular slime molds.

160

macrocyst

In cellular slime molds, a flattened, irregular structure, encircled by a thin membrane, in which zygotes are formed.

161

Annual Growth Cycle

goes seed to seed in 1 year

example: zinnia

162

Biennial Growth Cycle

goes seed to seed in 2 years

examples: swiss chard, carrots, beets, sweet William, parsley

163

Perennial Growth Cycle

goes seed to seed in more than 2 years

examples: herbaceous perennials and woody perennials

164

haploid (1n)

most fungi, algae

165

diploid (2n)

brown algae, some fungi (mycomycata)

166

Haploid-diploid (1n-2n)

most plant-like algae, bryophytes, all land plants

167

Why move onto the land?

- abundant and more consistent light for photosynthesis

- more plentiful and freely circulating CO2

- lack of competition from other organisms

168

What do Green Algae and Land plants have in common?

- chloroplasts with chlorophyll a, chlorophyll b and carotenoids

- cell walls containing cellulose

- food reserves - starch stored in plastids

169

fungal protists

slime molds and water molds

170

algae belong to

protista

171

Algae differ from plants in that

lack tissue differentiation and have no true roots, leaves, or stems

172

pyrenoids

organelles that synthesize and store starch

173

unicellular algae

consists of a Single Cell, most Aquatic Organisms,

form the PHYTOPLANKTON, produce half of the worlds CH and produce O2

174

colonial algae

consists of Groups of Cells acting in a coordinated manner. Some of these Cells Become Specialized. This allows them to move, feed, and reproduce efficiently.

175

Filamentous algae

Have a slender, rod-shaped Thallus, composed of rows of cells joined end to end.

- adaptation secures the algae in one place as it grows towards the sunlight at the water's surface

176

Holdfast

anchor the thallus to the ocean bottom

177

multicellular algae

Have a large, complex Thallus. The Leaf-like Thallus may be several centimeters wide but only TWO Cells Thick. Some have leaflike portions, and stem-like regions.

178

Heterokonts

organisms w 1 long-flagellum (tinsel) and 1 shorter flagellum (whiplash)

179

oomycetes

- unicellular to highly branched filamentous forms

- Asexual reproduction by zoospores

-Sexual reproduction = large immobile egg + small motile male gamete

180

Phytophthora

causes late blight in potatoes

181

plasmopara viticola

cases downy mildew in grapes

182

Pythium

causes seedling damping-off diseases

183

Isogamy

gametes morphologically indistinguishable

184

anisogamy

gametes different in appearance but not eggs and sperm

185

oogamy

large nonmotile eggs and small motile (usually) sperm

186

Diatoms

phytoplankton -fossil species identical to today's species (well-preserved due to cell walls)

cell walls made of silica and the varied shapes and beautiful ornamentation of these walls made the study of the diatoms a favored microscopically studied organism

187

Red Algae

-unicellular, multicellular

-freshwater, marine

-some used as agar (gelling agent made from cell-walls’ mucilage)

-some contributes coral reefs (secrete Ca-rich exoskeleton)

-most complicated life cycle

(1 gametophyta, 2 sporophyta)

188

Brown Algae

-largest, most complex algae

-most abundant sea weeds by seashores

-most have holdfast (basal extension attach it to solid objects)

-alt. generation common

189

Green Algae

-sharing features w land plants

-unicellular, colonial (Volvox)

-unicellular, filamnetous (spirogyra)

-complex, multicellular (Chara)

-some planktonik (floats)

examples: Chlamydomonas

190

Phylum Chlorophyta: Green Algae

- very diverse

- most similar to higher plants

- unicellular, filamentous, colonial, multicellular, motile and nonmotile

- oogamy, isogamy, anisogamy

- chlorophyll a and b, carotenoids •store starch in chloroplast

191

Phylum Chlorophyta : Representatives

Chlorella - unicells

Chlamydomonas - unicells

Spirogyra - filamentous

Volvox - colonial

Ulva - parenchymatous

Chara - parenchymatous

Fritschiella - parenchymatous

192

Asexual Reproduction

exist as a Flagellated Haploid Cell, First absorbs its Flagellum, then the Haploid Cell divides Mitotically up to 3X, and forms from 2-8 Haploid Flagellated Cells(ZOOSPORES), develop within the parent cell. These motile Cells break out of the parent cell, disperse, and eventually grow to full size.

193

Sexual Reproduction

- Begins with Haploid Cells dividing Mitotically to produce either "Plus" or "Minus" Gametes. + n - gamete comes in contact and Shed their Cell Walls.

-They Fuse and form a Diploid Zygote, w Thick Protective Wall.àZYGOSPORE.

-When favorable conditions exist, the Thick Wall Opens and the Zoospore emerges. It then undergoes Meiosis, forming Numerous Haploid Cells that grow into mature organisms.

194

Charales (stoneworts)

most complex green algae

- can reach > 10cm length

- Have rhizoid-like cells attach them to substrates

- Branches secrete CaCO3

-Leaflike structures whorled around a hollow stem

-lacking true roots, leaves or flowers.
-Growth attached to the pond bed without true roots.

-May densely “carpet” large areas of a lake or pond bottom and can reach the surface in shallow waters.

195

antheridium

A sperm-producing structure that may be multicellular or unicellular.

196

archegonium

A multicellular structure in which a single egg is produced; found in the bryophytes and some vascular plants.

197

sporangium

A hollow unicellular or multicellular structure in which spores are produced.

198

rhizoids

(1) Branched rootlike extensions of fungi and algae that absorb water, food, and nutrients;

(2) root-hair-like structures in liverworts, mosses, and some vascular plants, occurring on free-living gametophytes.

199

spermatogenous cell

The cell of the male gametophyte, or pollen grain, of gymnosperms, which divides mitotically to form two sperm.

200

venter

The enlarged basal portion of an archegonium containing the egg.

201

matroptrophy

Pertaining to a form of nutrition provided by the maternal gametophyte, such as a moss gametophyte providing nutrients to the zygote and developing sporophyte.

202

placenta

The part of the ovary wall to which the ovules or seeds are attached.

203

calyptra

The hood or cap that partly or entirely covers the capsule of some species of mosses; formed from the expanded archegonial wall.

204

seta

In bryophytes, the stalk that supports the capsule, if present; part of the sporophyte.

205

capsule

(1) In angiosperms, a dehiscent, dry fruit that develops from two or more carpels;

(2) a slimy layer around the cells of certain bacteria;

(3) the sporangium of bryophytes.

206

embryophytes

The bryophytes and vascular plants, both of which produce embryos; a synonym for plants.

207

sporopollenin

The tough substance of which the exine, or outer wall, of spores and pollen grains is composed; a cyclic alcohol highly resistant to decay.

208

protonema

The first stage in development of the gametophyte of mosses and certain liverworts; protonemata may be filamentous or platelike.

209

gametophore

In bryophytes, a fertile stalk that bears gametangia.

210

antheridiophore

In some liverworts, a stalk that bears antheridia.

211

elater

(1) An elongated, spindle-shaped, sterile cell in the sporangium of a liverwort sporophyte that aids in spore dispersal;

(2) clubbed, hygroscopic band attached to the spore of horsetails.

212

androecium

(1) The floral whorl that comprises the stamens;

(2) in leafy liverworts, a packetlike swelling containing the antheridia.

213

perianth

(1) The petals and sepals taken together;

(2) in leafy liverworts, a tubular sheath surrounding an archegonium and, later, the developing sporophyte.

214

hadrom

The central strand of water-conducting cells found in the axes of some moss gametophytes and sporophytes.

215

operculum

In mosses, the lid of the sporangium.

216

hydroids

Water-conducting cells of the moss hadrom; they resemble the tracheary elements of vascular plants, except for their lack of specialized wall thickenings.

217

leptoids

Food-conducting cells associated with the hydroids of some moss gametophytes and sporophytes; they resemble the sieve elements of some seedless vascular plants.

218

leptom

Food-conducting tissue consisting of leptoids; surrounds the hadrom in the axes of some moss gametophytes and sporophytes.

219

protracheophyte

An organism with branched axes and multiple sporangia, but with water-conducting cells similar to the hydroids of modern mosses rather than to the tracheary elements of vascular plants; an intermediate stage in the evolution of vascular plants, or tracheophytes.

220

tracheophyte

A vascular plant.

221

peristome

In mosses, a fringe of teeth around the opening of the sporangium.

222

epiphyte

An organism that grows upon, but is not parasitic on, another organism.

223

The Bryophytes

- no true roots, stems, leaves or flowers

224

Bryophytes : thallus

- filamentous, some mosses

- blocks/sheets of parenchyma (liverworts and hornworts)

225

Bryophytes: Asexual Reproduction

gemma cells break off and produce new plants

226

gemma

A small mass of vegetative tissue; an outgrowth of the thallus, for example, in liverworts or certain fungi; it can develop into an entire new plant.

cup-shape structures produced by thallus

227

Sexual Reproduction: Gametophyte

- visible and vegetative generation of the bryophytes

- Because sperms must swim through water to fertilize egg, bulk H2O is necessary

228

Sexual Reproduction: Sporophyte

- Grows out of and attached to the venter of the archegonium

- Gets all nutrients from gametophyte plant

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Liverworts

- no stomata but pores (analogous top stomata)

- bryophyta cells interconnected by plasmodesmata

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Hornworts

gametophyte: resembles liverworts

sporophytes: horn-like projections that rise from the gametophyte

- continues to grow throughout its life (basal meristem)

- as sporophyte grows longer, it splits into 2-halves lengthwise, release the spores

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Mosses

gametophyte: forms the green leafy structure

- it produces a sperm and an egg (the gametes) which unite, when conditions are right, to grow into the next generation: the sporophyte

- sporophyte is typically a capsule growing on the end of a stalk (seta)

- as the sporophyte dries out, capsule release spores which will grow into a new generation of gametophytes

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Kingdom PLANTAE

- adapted for land habitation

- vary in size

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Kingdom PLANTAE Multicellualr

a) photosynthetic pigments

- chlorophyll a and b

cuticle - covers the aerial parts to prevent dehydration

stomata - found in the epidermis of the aerial parts for gas exchange

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Gametangium

- general name for a sex organ

contains a sterile layer of cells - surrounds gametes and protects

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Archegonium

female gametangium

produces a single egg

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Antheridium

male gametangium

produces many sperm

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Development of the Zygote

- Egg is fertilized within the archegonium

- zygote - develops into a multicellular embryo in archegonium

- embryo - develops and differentiates further into a mature plant