Roots, Stems, and Leaves

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Roots, Stems, and Leaves

• Chapter 23 Dragonfly
• Chapter 35 Advanced Biology

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Biggest FlowerRafflesia arnoldii The largest
flower of any plant in the world is found on the
mottled orange-brown and white parasitic plant
Rafflesia arnoldii. Each bloom is 35.8 in wide
and can weigh up to 24.3 lbs with petals up to
0.75 in think.
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• You are studying a plant from the arid
  southwestern United States. Which of the
  following adaptations is least likely to have
  evolved in response to water shortages?
• a. closing the stomata during the hottest time
  of the day
• b. development of large leaf surfaces to absorb
  water
• c. formation of a fibrous root system spread
  over a large area
• d. mycorrhizae associated with the root system
• e. a thick waxy cuticle on the epidermis

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• A friend has discovered a new plant and brings it
  to you to classify. The plant has the following
  characteristics a taproot system with growth
  rings evident in cross section and a layer of
  bark around the outside. Which of the following
  best describes the new plant?
• a. herbaceous eudicot
• b. herbaceous monocot
• c. woody eudicot
• d. woody annual
• e. woody monocot

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I. Specialized Tissues in Plants

• A. Seed Plant Structure
• 1. Roots
• a. Absorb water
• b. Absorb minerals
• c. Anchor the plant
• d. Prevent erosion
• e. Protect plant from bacteria and fungi
• f. Hold plant upright

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• 2. Stems
• a. Carries nutrients
• b. Protects against predators and disease
• c. Few mm to 100 m long
• d. Must be strong
• Tallest Cactus Saguaro (Cereus giganiteus or
  Carnegiea gigantea) is the world's tallest
  cactus. The tallest specimen on record was found
  in the Maricopa Mountains, Arizona, USA in 1988
  and had branches that rose to a record height of
  58 ft.

http//ecoworld.com/plants/ecoworld_plants_home.cf
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• 3. Leaves
• a. Main site of photosynthesis
• b. Flat for high surface area
• c. Protect against water loss
• d. Adjustable pores

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B. Plant Tissue Systems
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B. Plant Tissue Systems

• 1. Dermal Tissue
• a. Skin of the plant
• b. Consists of a single layer of epidermal
  cells
• c. Thick waxy covering
• d. Guard cells regulate water loss through
  stomata

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• 2. Vascular Tissue
• a. bloodstream
• b. Xylem
• 1) water-conducting tissue

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• 2) tracheids
• a) long, narrow cells with walls that are
  impermeable to water
• b) have openings that connect cells to one
  another
• c) not alive

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• 3) vessel elements
• a) cells that die, lose their end walls, and
  act as pipes transporting water

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• c. Phloem
• 1) food-conducting tissue
• 2) sieve tube members
• a) similar to vessel elements, but the ends
  look like a sieve
• (sieve plate)

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• 3) companion cells
• a) surround sieve tube elements
• b) support the movement of substances

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• d. Vascular cylinder
• 1) a solid core of xylem and phloem in the root
• e. Vascular bundles
• 1) Strands of xylem and phloem in the root

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• 3. Ground Tissue
• a. All other tissues in plants
• b. Parenchyma
• 1) packed with chloroplasts
• 2) most photosynthesis occurs here

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• c. Collenchyma
• 1) strong, flexible cells
• 2) provide support for larger plants
• d. Sclerenchyma
• 1) thick, rigid cell walls
• 2) make cells tough and strong

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Root, Stem, and Leaf Tissues
e. Pith 1) ground tissue that is internal to
vascular tissue f. Cortex 1) ground tissue
that is external to vascular tissue
Leaf
Stem
Root
Dermal tissue Vascular tissue Ground tissue
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• 4. Plant Growth and Meristematic Tissue
• a. Indeterminate vs. Determinate Growth
• 1) Indeterminate Growth
• a) growth that occurs throughout a plants
  life never stops
• 2) Determinate Growth
• a) organism ceases to grow when reaches a
  certain size
• b) most animals and some plant organs such
  as leaves

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• b. Meristem clusters of tissue that are
  responsible for continued plant growth
• c. Meristematic tissue is the only plant tissue
  that produces new cells by mitosis
• d. Unspecialized cells

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• e. Apical meristerm
• 1) undifferentiated cells that divide to
  increase stem and root length
• 2) cause the plant to grow in length (primary
  growth)

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• f. Lateral Meristem
• 1) cause a growth in
• thickness
• (secondary growth)

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• 2) occurs in stems and roots of woody plants
• 3) vascular cambium and cork cambium adds
  layers of vascular tissue called secondary xylem
  (wood) and secondary phloem
• g. Differentiation process in which cells
  become specialized in structure and function

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Concept Map
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• An evolutionary adaptation that increases
  exposure of a plant to light in a dense forest is
• a. closing of the stomata.
• b. absence of petioles.
• c. lateral buds.
• d. intercalary meristems.
• e. apical dominance.

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• Which of the following is not a characteristic of
  parenchyma cells?
• a. thin primary walls
• b. lack of secondary walls
• c. flexible primary walls
• d. little metabolism and synthesis
• e. lack of specialization

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• Which of the following tissues is incorrectly
  matched with its characteristics?
• a. Collenchyma
• b. Epidermis
• c. Sclerenchyma
• d. meristematic tissue
• e. Parenchyma

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• Which of the following tissues is incorrectly
  matched with its characteristics?
• a. Collenchyma - uniformly thick-walled
  supportive tissue
• b. Epidermis - protective outer covering of
  plant body
• c. Sclerenchyma - heavily lignified secondary
  walls
• d. meristematic tissue - undifferentiated tissue
  capable of cell division
• e. Parenchyma - thin-walled, loosely packed,
  unspecialized cells

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• The vascular bundle in the shape of a single
  central cylinder in a root is called the
• a. cortex.
• b. periderm.
• c. stele.
• d. pith.
• e. endodermis.

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• The photosynthetic cells in the interior of a
  leaf are what kind of cells?
• a. parenchyma
• b. phloem
• c. collenchyma
• d. endodermis
• e. sclerenchyma

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II. Roots

• the surface of the roots of a rye plant once
  measured 600 square meters
• A. Types of Roots
• 1. Taproot
• a. Dicots
• b. Long and thick root

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• 2. Fibrous root
• a. Monocots
• b. Branched extensively

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B. Root Structure and Growth

• 1. Epidermis outside layer
• a. Protection
• b. Absorption
• c. Covered with root hairs
• 1) provides a large
• surface area

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• 2. Vascular cylinder
• a. Central cylinder of vascular tissue

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• 3. Large area of ground tissue between the
  epidermis and vascular tissue
• a. Cortex
• 1) spongy layer of ground tissue
• b. Endodermis
• 1) completely encloses the roots vascular
  subsystem

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• 4. Root cap
• a. Protects the root as it grows
• b. Secretes a slippery substance

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C. Root Functions

• 1. Anchor the plant
• 2. Uptake of Plant Nutrients
• a. Soil
• 1) Earths surface layer that supports plant
  life
• 2) good soil
• a) 25 air (CO2 and O2)
• b) 25 water
• c) 45 minerals
• d) 5 organic matter

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• 3) minerals
• a) sand - largest
• b) silt
• c) clay smallest
• 4) loam soil - best
• a) 30 sand, 40 silt, 30 clay
• b. Nutrients needed by plants
• 1) atmospheric macronutrients
• a) C
• b) H
• c) O

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• 2) Primary Macronutrients
• a) N
• b) P
• c) K
• 3) Secondary Macronutrients
• a) S
• b) Ca
• c) Mg

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• 4) Micronutrients
• a) B
• b) Cu
• c) Cl
• d) Fe
• e) Mn
• f) Mo
• g) Zn

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• 5) Mnemonic
• C. B. HOPKiNS CaFÈ Mighty good
• Closed Monday Morning See You Zen

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Essential Plant Nutrients
Role in Plant Proper leaf growth and color
synthesis of amino acids, proteins, nucleic
acids, and chlorophyll Synthesis of DNA
development of roots, stems, flowers, and
seeds Synthesis of proteins and carbs
development of roots, stems, and flowers
resistance to cold disease Synthesis of
chlorophyll Cell growth and division cell wall
structure cellular transport enzyme action
Result of Deficiency Stunted plant growth pale
yellow leaves Poor flowering stunted
growth Weak stems and stunted roots edges of
leaves turn brown Thin stems mottled, pale
leaves Stunted growth curled leaves
Nutrient Nitrogen Phosphorus Potassium Mag
nesium Calcium
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• 3. Active Transport of Minerals
• a. Passive transport vs. active transport

b. Active transport proteins use ATP to pump
mineral ions from the soil into the plant
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• 4. The high concentration of mineral ions in the
  plant cells causes water molecules to move into
  the plant via osmosis (passive transport)
• a. osmosis movement of water from an area of
  high concentration to an area of low concentration

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• 5. Osmosis and active transport move water and
  nutrients into the Vascular Cylinder
• a. The casparian strip allows nutrient ions and
  water to move into the vascular cylinder, but not
  out they are trapped
• 6. Root pressure - Because the nutrient ions and
  water molecules are trapped, they can only go up

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• The driving force that pushes the root tip
  through the soil is due primarily to
• a. continuous cell division in the root cap at
  the tip of the root.
• b. continuous cell division just behind the root
  cap in the center of the apical meristem.
• c. elongation of cells behind the root apical
  meristem.
• d. A and B only.
• e. A, B, and C.

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Transport in Roots Transport in Roots Transport in Roots
Questions Water Absorption Nutrient Uptake

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Transport in Roots Transport in Roots Transport in Roots
Questions Water Absorption Nutrient Uptake
1. How does the process occur?
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Transport in Roots Transport in Roots Transport in Roots
Questions Water Absorption Nutrient Uptake
1. How does the process occur? 2. List in order the root tissues involved in this process.
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III. Stems

• A. Stem Structure and Function
• 1. Functions
• a. Produce leaves, branches, and flowers
• b. Hold leaves up to the sunlight
• c. Transport substances between roots and
  leaves
• d. Some photosynthesize
• e. Some also serve as storage (tuber, bulb,
  corm, rhizome

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• 2. Structure
• a. Node
• 1) the point where
• leaves attach
• b. Internode
• 1) region between nodes
• c. bud
• 1) contain undeveloped tissue that can
  produce new stems and leaves

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B. Monocot and Dicot Stems

• 1. Monocot
• a. Vascular bundles (xylem and phloem) are
  scattered throughout the stem
• 2. Dicot
• a. In dicots and most gymnosperms vascular
  bundles are arranged in a cylinder
• b. Pith
• 1) the parenchyma cells inside the ring of
  vascular tissue

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C. Primary Growth of Stems

• 1. Primary Growth
• a. New cells are produced at the tips of roots
  and shoots
• 2. occurs at the tips of
• roots and shoots
• 3. takes place in all
• seed plants

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D. Secondary Growth of Stems

• 1. Secondary Growth
• a. Stems increasing in width
• b. In conifers and dicots, secondary growth
  takes place in lateral meristematic tissues
  called vascular
• cambium and
• cork cambium

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• c. Vascular cambium
• 1) lateral meristematic tissue produces
  vascular tissue increasing stem width
• d. Cork cambium
• 1) produces outer covering of stems

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• 2. Formation of Wood
• a. Heartwood
• 1) older xylem that no longer conducts water
• b. Sapwood
• 1) surrounds the heartwood, is usually
  lighter in color, and still conducts water

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• 3. Formation of Bark
• a. Bark
• 1) all of the tissues outside the vascular
  cambium
• 2) includes phloem, cork cambium, and cork

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• Which of the following is true about secondary
  growth in plants?
• a. Flowers may have secondary growth.
• b. Secondary growth is a common feature of
  eudicot leaves.
• c. Secondary growth is produced by both the
  vascular cambium and the cork cambium.
• d. Primary growth and secondary growth
  alternate in the life cycle of a plant.
• e. Plants with secondary growth are typically
  the smallest ones in an ecosystem.

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• The vascular system of a three-year-old eudicot
  stem consists of
• a. 3 rings of xylem and 3 of phloem.
• b. 2 rings of xylem and 3 of phloem.
• c. 2 rings of xylem and 2 of phloem.
• d. 3 rings of xylem and 1 of phloem.
• e. 2 rings of xylem and 1 of phloem.

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IV. Leaves

• A. Function
• 1. carry out photosynthesis
• B. Leaf Structure
• 1. Blade
• a. Thin, flattened sections to collect
  sunlight
• b. Simple or compound (consisting of many
  leaflets)
• 2. Petiole
• a. Attaches blade to stem

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C. Leaf Functions

• 1. Photosynthesis
• a. Mesophyll
• 1) this is where photosynthesis occurs

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• b. Palisade mesophyll
• 1) closely packed columnar cells that absorb
  light

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• c. Spongy mesophyll
• 1) loose tissue with many air spaces
  connected to stomata

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• d. Stomata
• 1) porelike openings in the underside of the
  leaf that allow CO2 and O2 to diffuse in and
  out of the leaf

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• e. Guard cells
• 1) control the opening and closing of the
  stomata

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• 2. Transpiration
• a. The loss of water through leaves

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• 3. Gas Exchange
• a. Plants keep their stomata open just enough
  to allow photosynthesis to take place but not so
  much that they lose an excessive amount of water
• b. High water pressure causes the guard cells
  to open the stomata
• c. Guard cells work to maintain homeostasis

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• Which of the following is incorrectly paired with
  its structure and function?
• a. Sclerenchyma -
• b. Periderm -
• c. Pericycle -
• d. Mesophyll -
• e. ground meristem -

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• Which of the following is incorrectly paired with
  its structure and function?
• a. Sclerenchyma - supporting cells with thick
  secondary walls
• b. Periderm - protective coat of woody stems
  and roots
• c. Pericycle - waterproof ring of cells
  surrounding the central stele in roots
• d. Mesophyll - parenchyma cells functioning in
  photosynthesis in leaves
• e. ground meristem - primary meristem that
  produces the ground tissue system

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• All of the following cell types are correctly
  matched with their functions except
• a. mesophyll-photosynthesis
• b. guard cell-regulation of transpiration
• c. sieve-tube member-translocation
• d. vessel element-water transport
• e. companion cell-formation of secondary xylem
  and phloem

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V. Transport in Plants

• A. Water Transport
• 1. root pressure, capillary action, and
  transpiration provide enough force to move water
  through the xylem up any plant

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• 2. Capillary Action
• a. Cohesion
• 1) molecular attraction of like substances
• b. Adhesion
• 1) molecular attraction of unlike substances
• c. Capillary action
• 1) the upward movement of a fluid against
  the force of gravity
• 2) due to cohesion and adhesion

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• 3. transpiration
• a. As water is lost through stomata, osmotic
  pressure moves water out of the vascular tissue

Evaporation of water molecules out of leaves.
Pull of water molecules upward from the roots.
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B. Nutrient Transport

• 1. nutrients are pushed through phloem
• 2. Source to Sink
• a. Pressure-Flow hypothesis
• - When nutrients are pumped into or removed
  from the phloem system, the change in
  concentration causes a movement of fluid in that
  same direction. As a result, phloem is able to
  move nutrients in either direction to meet the
  nutritional needs of the plant.

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Xylem
Phloem
Sugarmolecules
Phloem Transport
Source cell
Movementof water
Movementof sugar
Sink cell
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• The End

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Xylem
Phloem
Sugarmolecules
Phloem Transport
Source cell
Movementof water
Movementof sugar
Sink cell
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• THE END