Transcript Botany

Botany
Study of Plants
General Characteristics
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Autotrophs
Eukaryotes
400,000 known species
Cell walls
Plastids
Create food and habitat for animals
Phylum Bryophyta
• Non-vascular plants (no true roots,
stems or leaves)
• Must live in moist environment
• Must be small and close to ground
P. Bryophyta,
Class Muscopsida
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Mosses
9500 species
Small, grow in clumps
Reproduce by spores
Pioneer plants
P. Bryophyta,
Class Hepaticopsida
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Liverwarts
6000 species
Very small
Moist, warm environments
Vascular Plants
• Have vascular tissue
• 250,000 species
• Cell walls contain lignin (tough
material for support)
• Adapted to survive in tough
conditions
Structure 1
• Roots – Absorb moisture and
nutrients, anchor plants
• Leaves – Use chlorophyll to
produce food
• Stems: Transfer materials
between roots and leaves
Structure 2
• Vascular Tissue:
• Xylem – Water and minerals from
roots to other parts of the plants
• Phloem – Sugars and organic
material from leaves to other parts
of the plants
Vascular Plant Groups
• Seedless Plants
• Seed Plants
Seedless Plants
• Have sperm that swim to egg
cells (in dew)
• Simple plants
• Do photosynthesis
• 4 groups
Seedless Group 1
• Phylum Psilophyta – Whisk Ferns
Seedless Group 2
• Phylum Sphenophyta – Horse Tails
Seedless Group 3
• Phylum Lycophyta – Club Mosses
Seedless Group 4
• Phylum Pterophyta
• – Ferns
Seed Plants
• Reproduce with seeds
• Seeds contain plant embryo and
cotyledon (embryonic leaves)
• Seeds help survive poor
conditions
Groups of Seed Plants
• Gymnosperm – naked
seeds
• Angiosperm – Flowering
plants
Gymnosperms
• Seeds in cones
• Usually evergreens
• Leaves needle-like or scale-like
Phylum Coniferophyta
• Cone Bearers
• Pine Trees
Phylum Cycadophyta
• Cycads,
• palm-like
• (but not palms)
• Ancient group
Phylum Ginkgophyta
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Gingko
Leaves fan-shaped
Only one species
Ancient group
Phylum Gnetophyta
• Ex: Welwitschia, Ephedra
• About 70 species
• Assumed to be the closest
related to flowering plants
Angiosperm
• Flowering Plants
• About 235,000 species
Phylum Anthophyta
• Mature seeds are enclosed in
fruits
• Most species of plants
• Flowers are reproductive
structures
Class Monocotyledon
• Produce seeds with 1 embryonic
seed leaf
• Flower parts usually in threes
• Leaves with parallel veins
• Almost all are herbaceous
• Vascular bundles scattered
• Roots diffuse
Examples
Class Dicotyledon
• 2 Embryonic leaves (dicots)
• Flower parts in 4 or 5’s
• Leaf veins in a network
• Vascular Bundles in a circle
• Taproot
Examples of Dicots
Roots, Stems, and Leaves
Plant Organs
RECORD ALL DETAILS ON SLIDES
31, 49, 50
• Roots: *Absorb water and nutrients
*Anchor plants in ground
• Stems *support plant body
*transport nutrients among plant
parts
• Leaves *carry out photosynthesis
*funnel water to roots
sites for oxygen and
*exchange
carbon dioxide
Root, Stem, and Leaf Tissues
Section 23-1
Leaf
Stem
Root
Dermal tissue
Vascular tissue
Ground tissue
Tissue Systems
• Dermal:
Page 581
*outer covering of plants
*single layer of epidermal cells
*covered with waxy cuticle that
protects against water loss
• Vascular: *xylem and phloem carry water
and
nutrients
through
the
plant
Page 582
• Ground:
*parenchyma, collenchyma,
schlerenchyma, support the plant
and site of
Page 583
photosynthesis
• Meristematic: *only in tips of shoots and roots,
responsible for plant growth
Page 580
Fibrous Roots vs. Taproots
• Fibrous roots are shallow and wide-reaching
• Taproots are DEEP and concentrated
downwards
See pages 584-585 in text
Figure 35.14 Primary growth of a root
Water Transport in a Root
Section 23-2
Epidermis
Endodermis
Cortex
Casparian strip
Cell wall
Root
hairs
Cortex
Active transport
of minerals
Movement of water
by osmosis
Cell membrane
Phloem
Xylem
Vascular
Cylinder
Figure 35.3 Radish root hairs
Figure 35.18 Organization of primary tissues in young stems
Layers of a Tree Trunk
Section 23-3
Wood
Bark
Cork
Contains old,
nonfunctioning
phloem that
protects the tree
Xylem:
Heartwood
Contains old,
nonfunctioning
xylem that helps
support the tree
Cork Cambium
Produces
protective layer
of cork
Phloem
Transports sugars
produced by
photosynthesis
Xylem: Sapwood
Contains active xylem that
transports water and
minerals
Vascular Cambium
Produces new xylem and
phloem, which increase
the width of the stem
Stem adaptations
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See page 594
Tuber – stem growing underground
(potato)
Bulb – central stem surrounded by leaves
(amaryllis)
Corm – thickened stem that stores food
(gladiolus)
Rhizome – horizontal, underground stem
(ginger)
Figure 35.5 Simple versus compound leaves
The Internal Structure of a Leaf
Section 23-4
Cuticle
Veins
Epidermis
Palisade
mesophyll
Xylem
Phloem
Spongy
mesophyll
Epidermis
Stoma
Guard
cells
Vein
Section 23-5
Transpiration
A
B
Evaporation of water
molecules out of leaves.
Pull of water molecules upward
from the roots.
Section 23-4
Function of Guard Cells –
gas exchange (CO2 in, O2 out)
Guard cells
Guard cells
Inner cell wall
Inner cell wall
Stoma
Stoma Open
Stoma Closed
Figure 35.6 Modified leaves: Tendrils, pea plant (top left); spines, cacti (top right); succulent (bottom
left); brightly-colored leaves, poinsettia (bottom right)
Water tranport
• Capillary action – water moves upward
through narrow tubes against the force of
gravity (adhesion and cohesion)
Food Transport
• Movement from source (where sugars are
produced by photosynthesis) in leaves to
where sugars are used or stored
Compare/Contrast Table
Section 24-1
Comparing Plant Propagation Methods
Method
Procedure
Cuttings
A length of stem that includes lateral buds is cut from the
parent plant and partially buried in soil or rooting mixture to
take root.
Grafting
A piece of stem is cut from the parent plant and
attached to another plant.
Budding
A piece of lateral bud is cut from the parent plant and
attached to another plant.
Vegetative reproduction: takes place naturally;
parent plant puts out runners that grow new
plants (Ex. Strawberries)
Plant Responses (ADAPTATIONS)
• Tropisms: responses of plants to
environmental stimuli
• Types of tropisms:
gravitropism
phototropism
thigmotropism
Gravitropism and Phototropism
Gravitropism: response of a plant to gravity –
stems go up, roots go down
Phototropism: response of a plant to light
(“bending” toward the light)
Meristems control plant
growth….
Thigmotropism
• Response of plants to touch
• Can stunt growth
• Can cause “twining” of plant tendrils with
vines and climbing plants
*can have as a quick response – Venus
flytrap
Photoperiodism and Flowering
Section 25-2
Short-Day Plant
Midnight
Noon
Long Day
Midnight
Noon
Short Day
Midnight
Noon
Interrupted Night
Long-Day Plant
Compare/Contrast Table –
plant adaptations
Section 25-3
Comparing Carnivorous Plants, Epiphytes, and Parasites
Characteristics
Carnivorous Plants
Epiphytes
Parasites
Environment
bog
host plant
host plant
Method of
obtaining nutrients
leaves that trap and gather moisture
digest insects
from rainfall and
produce their own
food
extract moisture
and nutrients from
host plant
pitcher plant,
sundew, Venus’
flytrap
dodder, mistletoe
Examples
Spanish moss,
orchid