Transcript All About Plants

All About Plants
What is a Plant?
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An autotroph
A producer
A multicellular eukaryote
Perform photosynthesis
Includes trees, shrubs, grasses, mosses, and
ferns.
• Aquatic and terrestial
• Over 270,000 species identified
• THEY ARE ALIVE!!!!!
What a Plant Needs to Survive
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Sunlight
Water and Minerals
Gas Exchange
Movement of Water & Nutrients
Plant Life Cycle
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Plants have two
alternating phases, a (2N)
dipoid phase and an (N)
haploid phase.
2N is the sporophyte
N is the gametophyte
The haploid gametophyte
stage produces eggs &
sperm
The diploid sporophyte
stage produces spores
Types of Plants
1. Nonvascular Plants
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Mosses, liverworts, hornworts
2. Vascular Plants
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Seedless
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Clubmosses, horsetails, ferns
Seed
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Gymnosperms
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Conifers
Angiosperms
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Flowering Plants
Nonvascular Plants - Bryophytes
Liverworts
Seedless Vascular Plants
Clubmoss
Ferns
Horsetails
Seed Plants -- Gymnosperms
• Cone-bearers
cycads
Ginkgoes
Seed Plants -- Angiosperms
Stinking corpse lilly
Plant Tissue Systems
• Dermal Tissue
• The skin of the plant. The outmost layer of
cells. Waxy layer helps the protect against
water loss.
• Vascular Tissue
• Transport system that moves water and
nutrients throughout the plant.
• Ground Tissue
• Cells that lie between the dermal and vascular
tissue.
• In leaves these cells are packed with
chloroplasts and are the site of
photosynthesis.
Roots
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Anchors plant
Absorbs water &
nutrients
Growth occurs at the
apical meristem
Root cap protects apical
meristem
Root hairs help absorb
water and minerals and
increase the surface area
of the root
The core of the root is
called the vascular
cylinder & contains
xylem & phloem
Taproots vs fibrous roots
Taproots grow deep to reach
water.
Taproots may store food
(carrots & beets).
Fibrous roots grow near the
surface and spread out to collect
water.
Fibrous roots like in grasses help
prevent erosion.
Stems
• Stems produce leaves,
branches, and flowers
• Stems hold leaves up
to the sunlight
• Stems transport
substances between
roots and leaves
• Xylem and phloem
form continuous
tubes from the roots
through the stems to
the leaves
Woody Stems
Monot vs. Dicot
Monocot
Dicot
Vascular bundles scattered
throughout the stem
Vascular bundles are arranged
in a ring
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Dendrochronology (Tree Time)
Tree rings tell how wet or
dry the growing seasons
were, when a fire swept
through the area, or when
damage occurred.
Each ring has two colors:
the light color is the wet
season growth and the dark
color is the cold or dry
season growth. If the light
color portion of the ring is
narrow, then there was not
much rain that year.
When aging a tree, just
count either the light or the
dark portion, not both.
Leaves
Leaf Function
• Photosynthesis
• Transpiration
• Gas exchange
• Monocots have
parallel veins
• Dicots have branched
veins
Dicot
Monocot
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Stomata on the
underside of leaves for
gas exchange (CO2 &
O2)
Two guard cells on
either side of the
stomata open & close
the openings
When guard cells LOSE
water, the stoma
CLOSE, while the
stoma OPEN when
guard cells gain water
& swell
What time of day would
the stoma be closed?
Adaptations of Leaves
Seeds
• Seeds may be
dormant (inactive)
for weeks or years
protected by their
seed coat
• Seeds contain a
plant embryo and
endosperm
Dicot Seed Germination
Seed Dispersal
Water & Nutrient Transport
• Vascular tissue conducts water &
nutrients
• The 2 types of vascular tissue are xylem
& phloem
• Xylem carries water and dissolved ions
from the roots to stems and leaves
• Phloem carries dissolved sugars from the
leaves to all other parts of the plant
Flowers
• Flowers are the
reproductive part of
a plant.
• Bright colors,
attractive shapes,
and fragrant aromas
help flowering
plants attract their
pollinators (insects,
birds, mammals...)
Pollination
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Wind, water, and animals help spread pollen
As pollinators drink nectar or eat the fruit, pollen
gets on their bodies and is spread to other flowers
Self pollination occurs whenever pollen from a flower
lands on the stigma of that SAME flower (pea plants)
Cross pollination occurs whenever pollen is spread to
a different flower producing hybrids
When pollen lands on the stigma, a pollen tube grows
through the style to the ovary
Two sperm travel down the pollen tube --- one
fertilizes the egg and the other join with polar nuclei
to form endosperm (stored food for Seed)
Called Double Fertilization
Tropisms
Gravitropism: gravity effect
• Roots have +gravitropism
• Stems have -gravitropism
Phototropism: the sun effect
• Phototropism causes a plant
to grow toward a light
source.
Thigmotropism
Carnivorous Plants
• Some plants grow in environments that
have low concentrations of nutrients in the
soil.
Specialized leaves trap and
digest insects for nutrients.