Transcript PLANTS

KINGDOM PLANTAE
Botany = the study of plants
Characteristics That All Plants Have in Common :
•Eukaryotic
•Multicellular
•Autotrophic
•Cell Walls made of cellulose
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Menu of Knowledge
Plant Classification
Plant Body Parts
Transport of Materials
In Plants
Plant Reproduction
Growth of Plants
Plant Hormones
Tropisms and
Photoperiodism
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Plant Classification
Kingdom Plantae
Non-Vascular
Seedless
Vascular
Produce Seeds
Gymnosperms
Angiosperms
Monocots
Dicots
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Non-Vascular Plants
Non-Vascular Plants = plants without tubes for
transporting water, minerals, and organic
molecules (such as sugar).
Examples of non-vascular plants = mosses and
liverworts. These are called Bryophytes.
Moss
Liverwort
Bryophyte Reproductive Cycle
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Vascular Plants
Vascular plants = plants with tubes to transport
water, minerals, and organic molecules (such as
sugars).
Examples of Vascular Plants = all plants
except mosses and liverworts
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Seedless Plants
Seedless Vascular Plants = plants with transport
tubes but do NOT produce seeds
Examples = Ferns and Horsetails
Fern Life Cycle
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Plants That Produce Seeds
All plants except mosses (and other Bryophytes)
and ferns are plants that produce seeds.
There are two groups of plants that produce
seeds :
Gymnosperms and Angiosperms.
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Gymnosperms
Gymnosperms = “naked seeds” or unprotected seeds
All plants that have transport tubes and produce
seeds, but have the seeds unprotected are
Gymnosperms.
Examples of Gymnosperms = pine trees, fir trees,
‘conifers’, the “Christmas Tree” group.
MALE
FEMALE
LIFE CYCLE OF
GYMNOSPERMS
The nature of cones (male vs
female...)
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Angiosperms
Plants with protected seeds, or
Flowering Plants
All plants EXCEPT mosses, ferns, pine trees and
their relatives are Angiosperms.
Angiosperms can be divided into two groups :
Monocots and Dicots
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Monocots vs. Dicots
All plants EXCEPT mosses, ferns, pine trees and
their relatives are Angiosperms.
All angiosperms are either monocots or dicots.
Monocots and Dicots are the two divisions of
Angiosperms (flowering plants). They are
different based on the characteristics described
on the next slide.
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Monocots vs Dicots
• Monocots
• Have one seed leaf
(cotyledon)
• Have fibrous roots
• Have parallel leaf
veins
• Have flower parts in
3’s
• Dicots
• Have 2 seed leaves
(cotyledons)
• Have tap roots
• Have Pinnate or
Palmate leaf vein
pattern
• Have flower parts in
4’s or 5’s
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Examples of Monocots and Dicots
• Monocots
• Dicots
• Grass, tulips, corn,
wheat, daffodils, iris,
Palm trees.
• All flowering plants
except the Grass
families and the Bulb
families.
• These are the most
successful plants on
Earth.
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Plant Body Parts
The body of a plant is composed of :
Roots
Stems
Leaves
Flowers
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Plant Body Parts - Roots
Functions :
1. Anchoring and stability
2. Absorb water and minerals
from the soil
Monocots
Dicots
Root Hairs :
microscopic threads growing on roots that increase
surface area of the root for better absorption of water and minerals.
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Plant Body Parts - Stems
Functions
1. transport materials throughout the plant
2. support the plant & hold the leaves up to
the sunlight
http://www.ars.usda.gov/
s/kids/plants/story1/treeb2.gif
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Cross-Section of a Stem
DEFINE : phloem ; xylem ; cambium ; sapwood ; heartwood ; annual ring
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Plant Body Parts - Leaves
Functions :
1. To perform photosynthesis to make sugars and other
organic compounds.
2. To allow for exchange of gases with the atmosphere (CO2 in
and O2 & H2O out).
Veins
Cuticle
Mesophyll
http://fig.cox.miami.edu/~cmallery/150/phts/leaf.jpg
Stomata
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Plant Body Parts – Leaves
(Continued)
Veins = tubes (vascular tissue) to transport water, minerals, sugars,
& other organic molecules.
= 2 types of tubes : Xylem transports water & minerals.
Phloem transports sugars & organics.
Cuticle = waxy layer on leaf surface for water-proofing.
http://www.emc.maricopa
.edu/faculty
/farabee/BIOBK/C4leaf.gif
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Plant Body Parts – Leaves
(Continued)
Cuticle
http://sci.gallaudet.edu/soarhigh
2002/amandakrieger/leafinsideparts.jpg
Vein
Mesophyll = “middle” of leaf made
of cells that are green with
chlorophyll and do photosynthesis.
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Plant Body Parts – Leaves
(Continued)
Stomata = openings (holes), mostly on the underside of
leaves to allow for exchange of gases (CO2 in and O2 & H2O out).
Guard Cells = two cells that surround the stomata.
They can
open or close to regulate water loss and gas exchange.
Stomata
Guard Cells
Closed Stomata
Open Stomata
These are microscope images from the underside surface (epidermis) of a leaf.
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Plant Body Parts - Flowers
Flowers = the reproductive structure of a flowering plant
(flowering plants = angiosperms).
Flowers have three primary parts: male, female, and sterile
(protection & attraction) parts.
1. Male parts = stamen (made of filament & anther)
2. Female parts = carpel (made of stigma, style, & ovary)
3. Sterile parts = sepals and petals
http://www.enchantedlearning.com/subjects/plants/printouts/floweranatomy.shtml
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Plant Body Parts – Flowers
(Continued)
http://kvhs.nbed.nb.ca/gallant/biology/flower.jpg
Click for
Plant Reproduction
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Transport of Materials in Plants
Transport of materials in plants occurs through
two types of tissue: xylem and phloem
1. Xylem = dead cells with thick cell walls that transport water and
minerals up a plant to other plant parts.
= “wood” is xylem tissue
2. Phloem = cells (found on the inside of bark) that transports
sugars and organic molecules from the leaves to other plant
parts.
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Transport of Materials in Plants
(Continued)
Transport of Water and Minerals :
Occurs in xylem tubes
Water and minerals travel from roots to rest
of the plant
Evaporation of water from leaves “pulls”
water through the plant
Evaporation of water from leaves is called
transpiration
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Transport of Materials in Plants
(Continued)
Transport of sugars and organic molecules :
Occurs in phloem tubes
Sugars and organic molecules travel from leaves
(where photosynthesis occurs) to other plant parts
(ROOTS, STEMS, FLOWERS…)
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Growth of Plants
Plants are either annuals, biennials, or perennials.
Plants have indeterminate growth – they continue to grow
throughout their lives.
Plant growth in length is called primary growth and it only
occurs at the tips of roots and stems. The tips of roots and
stems where cell division for plant growth in length occurs are
called apical meristems.
Plant growth in thickness is called secondary growth. This
occurs in the lateral meristem (= vascular cambium) which is
located between the xylem and phloem of a stem.
Annuals, Biennials,
Perennials
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Plant Reproduction
Male part of flower = stamen, which produces pollen
in the anther of the stamen. Pollen contains plant
sperm.
These images are pollen grains containing plant sperm.
Female part of flower = ovary, which is at the base of
the carpel and produces the egg.
Click here to review Flower Anatomy
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Plant Reproduction - Pollination
Pollination = transfer of pollen (containing sperm)
from the anther of a flower to the stigma of the carpel
of a flower.
Pollination & Fertilization
http://www.urbanext.uiuc.edu/gpe/glossary/fertilization.html
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Plant Reproduction
(Continued)
Seed = a protective structure that contains the
plant embryo and stored food and is covered with
a protective seed coat.
The functions of the seed are to protect
and nourish the embryo.
Seeds can remain dormant for years before
germination.
Seeds are dispersed (transported) by
animals eating them or carrying them
to other locations.
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Plant Reproduction
(Continued)
Fruit = a ripened ovary that protects the seeds of a
plant. The ovary is the base of the carpel at the lower
end of a flower.
The fruit contains the seeds. The fruit and seeds are
eaten by animals, the fruit is digested and the seeds are
passed through the animal digestive tract and deposited
in the ground away from the parent plant. This is one
way seeds can be dispersed (another way is by the wind,
like in dandelions and most trees). Examples of ripened
ovaries (fruit) = squash, cucumbers, & tomatoes.
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Plant Hormones
Hormones = proteins made and released from
one part of a plant that affect a different part of the
plant.
Important plant hormones :
1. auxins
2. cytokinins
3. ethylene
4. gibberellins
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1. Auxins :
Plant Hormones
(continued)
Where Produced = At the tips of stems
Functions = Stimulates cell elongation ; controls
apical dominance ; functions in tropisms.
Apical Dominance = the tendency for plants to
grow upward (towards sunlight) and inhibit side
(axillary) shoots from forming. Auxins control
this.
(Pruning house plants cuts off
the tips of plants, removing
auxins, and letting side
branches grow. This results in
‘fuller’ or ‘bushier’ plants.)
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Plant Hormones
(continued)
2. Cytokinins :
Where Produced = roots
Functions = Stimulates cell division; stimulates
germination of seeds.
3. Ethylene :
Where Produced = in fruits
Function = Ripening of fruit
Unique Characteristic = ethylene is a gas. One over-ripe
fruit in a bag can cause all other fruits in the bag to overripen. (“One bad apple can spoil the whole barrel”)
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Plant Hormones
(continued)
4. Gibberellins :
Where Produced = Tips of stems and in seeds
Functions = Stimulates stem elongation; stimulates
germination of seeds.
Tall plant has Gibberellins,
Short plant does not.
http://www.usu.edu/
cpl/images/29lu1sd.jpg
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Tropisms and Photoperiodism
Tropisms = the growth of a plant in a certain direction in
response to a stimulus.
1. Phototropism (bending in response to light)
2. Gravitropism (bending in response to gravity)
3. Thigmotropism (bending in response to contact)
Photoperiodism = any response of a plant that is linked
to day length (ex = flowering, leaves changing color, etc.)
Coiling in response
to touch
Bending in response
to light
Roots bending
towards gravity
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Selected Vocabulary
• Annual ring = a light-colored ring of spring/early
summer xylem growth and a dark ring of late summer
xylem growth.
• Apical meristem = tips of stems and roots where cell
division and primary growth (growth in length) occurs.
• Heartwood = oldest xylem in center of trunk that no
longer transports water because the cells are filled with
plant wastes (it’s a darker color).
• Sapwood = newer xylem that can still transport water
(it’s a lighter color).
• Vascular cambium = ring of tissue between xylem
and phloem that divides to produce new xylem and
phloem and causes secondary plant growth (growth in
thickness).
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