Video

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Video 3 Plants-Tissues, Nutrition Transport

• What area of the plant does Dr. Ann Hirsch study?
• How are ground, vascular, and dermal tissues
  different from each other? (pg. 717)
• Where in the plant does primary growth occur in
  plants and how is it different from secondary
  growth? (pg. 720)
• How is springwood different from summerwood in
  dicots (727)
• Briefly, in your own words, describe and explain
  the cohesion-tension theory? How does water
  plant and how is it pulled into the roots through
  the xylem?( leave the p.748)
• Name three essential nutrients that plant must
  have. How do plants obtain these nutrients? (pg.
  758)
• What is meant by the pressure flow theory?
  Where in the plant do we see this phenomenon?
  (pg. 753)
• Important Text Pages Ch. 35 - 37
• Write the title for each segment and FIVE
  statements for each segment. Include key terms
  mentioned for each statement.

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Plant Tissues (Ch. 35)
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Introductory Questions 6

• Using Pgs. 718-719 name the three types of tissue
  systems found in plants. Rank the tissues
  according to their flexibilities?
• How can we tell the difference between
  Parenchyma, Collenchyma, and Sclerenchyma?
• Tracheids and vessel elements are part of the
  vascular tissue called .
• How is the stele in monocots different from the
  stele in the dicots?
• Lateral roots that form arise from the _________.
  
• How is primary growth different from secondary
  growth? The specific areas that plant grow in
  their body are known as .
• An increase in girth is due to cell division
  occurring in the .

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Information about Plant Morphology

• See Pages 712-716
• These pages provide information that can be
  helpful for your Plant adaptation research
  project
• Leaf morphology growth habits are discussed
• Also see Ch. 50 to review the climatic zones
  (biomes)

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Overview of the Plant Body

• Shoots consist of stems, leaves, and flowers with
  internal pipelines for conduction

• Stems are frameworks for
  upright growth and
  display of flowers
• Leaves have photosynthetic cells
• Flowers are displayed to pollinators

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Overview of the Plant Body

• Roots usually grow below ground
• Absorb water and minerals from soil
• Conduct nutrients upward
• Store food
• Anchor and support plant

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Angiosperm structure

• Three basic organs
• Roots
• Stems
• Leaves

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Overview of the Plant Body(Pg. 713)
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Three Regions of a Plant
Leaves
Stems
Roots
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Cross Sections of Plant
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3 Types of Tissue (Pg. 717)

• Ground Tissue System
• Most extensive, makes up bulk of plant
• Vascular Tissue System
• Conducting tissues that distribute water and
  solutes throughout plant
• Dermal tissue system
• Covers and protects plant surfaces

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3 Types of Cells
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Simple Tissues

• Parenchyma cells
• Most common ground tissue
• Cells are active at maturity
• Retain capacity to divide
  heal
• Participate in
  photosynthesis, storage,
  secretion

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Simple Tissues

• Collenchyma cells
• Thicken and strengthen plant
• Pectin in the walls gives flexibility

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Simple Tissues

• Sclerenchyma cells
• Support and protect mature plant parts
• Lignin in cells anchors,
  waterproofs, and protects
• Long tapered fibers flex
  and twist
• Thickened sclereids
  form nuts pits

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Roots
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Types of Roots Structures

• Taproots -observed in many dicots
  gymnosperms
• Fibrous roots -has several adventitious
  branching
• Roots cap -orientates the direction of
  growth
• Roots hairs - increases the surface area and
  absorption of water and nutrients

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Primary Tissues of Roots

• Stele- the vascular bundle where both xylem and
  phloem develop
• Pith central core of stele in monocot
  parenchyma cells
• Cortex region of the root between the stele and
  epidermis (innermost layer endodermis)
• Lateral roots arise from pericycle (outermost
  layer of stele) just inside endodermis, cells
  that may become meristematic
• Pericycle cells that give rise to lateral roots
  and lateral meristems

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Internal Structure of Roots

• Root Cap dome-shaped cell mass at root tip
• Protects apical meristem, pushes through soil
• Epidermis absorptive interface
• Root hairs increase surface area

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Structure of Roots
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Internal Structure of Roots

• Vascular cylinder surrounded by cortex w/ air
  spaces for O2 respiration
• Pericycle meristematic, makes
  lateral
  roots

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Cross Section of a Root
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Two Pathways for water Movement

• Apoplast along the cell walls between cells
  within pores
• Symplast Through the cells cytoplasm

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Movement of water in Roots
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Casparian Strip

• Band-like region of the endodermis
• Acts like mortar between bricks
• Contains suberin (fatty waterproof)

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Internal Structure of Roots

• Vascular cylinder surrounded by cortex w/ air
  spaces for O2 respiration
• Pericycle meristematic, makes
  lateral
  roots

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Endodermis - solute control
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Overall Flow of Water into a Root

• Root hairs/epidermis
• ?
• Cortex
• ?
• Endodermis
• ?
• Pericycle
• ?
• Root Xylem

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Composition of Soil

• Inorganic particles 45 (rock weathering)
• Organic matter 5 (waste, humus)
• increases water holding capacity
• Water 25
• Air space (pores) 25
• Soil particles - tend to negatively charged
• Hold cations well (Mg, Ca, Na, K)
• Roots take up cations through cation exchange
• Anions not held tightly washes out easily

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Structure Texture of Soil

• Determined by weight relative size
• (less than 0.002mm)
• Gravel ? Sand ? Silt ? Clay
• -stones (2mm to 0.02mm) (0.02 mm to
  0.002mm)
• -rocks
• (less than 2mm)

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The Uptake of Anions

• Roots secrete protons (Hs) in exchange for
  other cations in the soil.
• Active transport
• pH-the more acidic the soil is the less ability
  plants are able to bind to cations.
• Ions such as K, Ca2, Mg2, etc

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Cation Exchange in Roots
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Cation Exchange in Soil
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Important Nutrients in Plants
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Legumes-Nitrogen Fixation
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Guttation (pg. 746)

• Water is forced out (mistaken for dew)
• Occurs when transpiration is small
• Soil moisture is high
• Occurs at night
• Water continues to move into the roots increasing
  the pressure

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Modified Specialized Roots
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Specialized Roots

• Prop Roots hold the plant upright
• Pneumatophores O2 into submerged roots
• Contractile roots pulls plant deeper
  within the soil
• Storage Roots Large, bulbous

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Storage Roots

• Store energy for dormant season
• Major food crops

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Prop Roots

• Anchor roots
  in watery
  habitats
• Mangroves,
  cypress

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Bacteria and how it helps to from Nitrates in soil
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Aerial Roots

• Absorb oxygen in oxygen-poor water
• Mangrove cypress knees

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Epiphytes

• Use other plants as a substrate
• Not parasitic
• Gather
  water
  nutrients
  from rain
  
  and humus

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Three Regions of a Plant
Leaves
Stems
Roots
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Transport Growth
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Xylem Phloem Tissue
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Plant Growth-involves Meristems
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Primary vs. Secondary Growth

• All plants have secondary growth
• Herbaceous plants only have primary growth
• Woody stem have primary and secondary growth
• Primary growth apical meristem
• Secondary growth lateral meristems

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Meristems (Pg. 680-683)

• Apical meristem (embryonic cells)
• At the tips of roots and shoots
• Responsible for growth and elongation
• Lateral meristems
• Responsible for increase in diameter of roots
  and stems (increases girth)
• Vascular cambium and cork cambium two kinds of
  lateral meristems
• Secondary growth adds wood

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Formation of Stems Leaves

• Leaf primordia develop from apical meristem
  as
  
  primary
  shoot
  grows

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Primary growth

• Roots
• root cap protection of meristem
• zone of cell division primary (apical) meristem
• zone of elongation cells elongate pushes root
  tip
• zone of maturation differentiation of cells
  (formation of 3 tissue systems)

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Secondary Growth-Woody Plants

• Involves two Lateral Meristems
• Vascular cambium
• Cork cambium (outer bark)Periderm
• Secondary xylem Wood
• Secondary Phloem inner bark

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Vascular Tissue

• See Chapter 33
• (Pgs. 712-717)

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Introductory Questions 7

• Observe the two cross sections on pages 705
  706. What organisms did these images come from?
  Which one is a dicot and a which one is a
  monocot? How do you know?
• What is the driving force behind the movement of
  water in the xylem and sugar through the phloem
  in plants?
• Name the two types of lateral meristems seen in
  woody plants. What purpose do rays serve?
• How much water pressure can accumulate in the
  roots?
• Briefly explain what guttation is and why it is
  more significant in smaller plants.

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Flow of Critical Molecules in a Plant
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Transportation Directions
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Complex Tissues - Xylem

• Conducts water and minerals as hollow pipelines
• Water flows
  from cell to
  cell
  through
  pits in walls
• Mechanically
  supports the
  plant

Vessel Members Tracheids
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Water Transportation
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Cross Sections of Plant
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Transpiration
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Water Flow Potential
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Vascular Tissues - Phloem

• Transports sugars other solutes

Sieve Tube Cell Longitudinal sec.
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Vascular Tissues - Phloem

• Sieve tube cells lose nucleus when mature
• Cytoplasm is
  interconnected
  between
  neighboring
  cell walls
  
  through pores

X - sec.
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Water movement in Phloem
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The Source Sink (Phloem)
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Vascular Tissues - Phloem

• Companion cells next to sieve tube
• In mitosis, makes sieve tube companion

X - sec.
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Vascular Tissues
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Stems
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Non-woody Woody Plants

• Most monocots non-woody (herbaceous)
• Dicots and gymnosperms are
  woody show secondary
  growth.

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Function of a Stem

• Support leaves reproductive struct.
• Internal trasnport
• Produces new living tissue
• ALL Stems have
• -buds
• -nodes internodes
• -leaf scars
• -lenticels (O2 can diffuse in)

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Primary Tissues of Stems

• Vascular bundles (xylem and phloem)
• Surrounded by ground tissue (xylem faces pith and
  phloem faces cortex)
• Mostly parenchyma some collenchyma and
  sclerenchyma for support

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Wood Cross Section
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Layers of Wood
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Tissue Layers of Wood
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Tree Rings

• Vascular cambium is inactive part of the year in
  cold or dry regions

• Spring wood lots of water, large xylem cells
• Summer wood drier, smaller xylem

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Vascular Cabmium-
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• Rings appear as alternating light bands of spring
  wood and dark bands of summer wood

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Secondary Growth

• Two lateral meristems
• vascular cambium produces secondary xylem
  (wood) and secondary phloem (diameter increase
  annual growth rings)
• cork cambium produces thick covering that
  replaces the epidermis produces cork cells cork
  plus cork cambium make up the periderm lenticels
  (split regions of periderm) allow for gas
  exchange bark all tissues external to vascular
  cambium (phloem plus periderm)

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Growth of Secondary Xylem Phloem
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Summary of primary secondary growth in a woody
a stem
PRIMARY PRIMARY LATERAL
SECONDARY MERISTEMS TISSUES
MERISTEM TISSUES
Protoderm Epidermis Secondary
phloem Primary phloem Vascular
Procambium cambium Secondary Primary
xylem xylem Ground meristem Ground Pith
tissue Cortex Cork cambium Cork
Apical meristem of stem
Periderm
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Summary of primary secondary growth in a woody
a stem
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Cork Cambium

• Produces cork on its outer face

• Together
  with epidermis,
  makes BARK

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Rays

• Carry nutrients water in lateral directions

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Banyon Trees

• Branches grow downward to buttress trunk in poor
  soil
• Grow roots to gather added minerals

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Baobab Tree

• Trunk swells in rainy season
• Stores water during dry season

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Rubber Trees

• Sap is collected seasonally via shallow, winding
  cuts in bark
• Pure latex
• Rubber trees conserve tropical forest

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Introductory Questions 7

• Observe the two cross sections on pages 705
  706. What organisms did these images come from?
  Which one is a dicot and a which one is a
  monocot? How do you know?
• What is the driving force behind the movement of
  water in the xylem and sugar through the phloem
  in plants?
• Name the two types of lateral meristems seen in
  woody plants. What purpose do rays serve?
• How much water pressure can accumulate in the
  roots?
• Briefly explain what guttation is and why it is
  more significant in smaller plants.

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Primary Tissues of Stems

• Vascular bundles (xylem and phloem)
• Surrounded by ground tissue (xylem faces pith and
  phloem faces cortex)
• Mostly parenchyma some collenchyma and
  sclerenchyma for support

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Key Points to remember regarding Stems

• Primary vs. secondary growth
• Meristems apical lateral
• Vascular cambium Cork cambium
• Layers of tissue pith ? bark
• Rays
• Xylem phloem transportation forces
• Water potential/Source sink

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Leaves Structure Function

• Chapter 32

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Introductory Questions 8

• Where is the casparian strip located?
• Why must plants use active transport in order to
  take in ions into the root hair cells?
• Name the two types of cells that make up the
  mesophyll layers in a leaf. What kind of tissue
  (cell types) are they?
• Briefly explain how the stomata open and close.
  Name the ions involved. What color light cause
  the stomata to open?

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Leaf Morphology
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Leaf Morphology-Chapter 32

• Leaves can be used to identify different species
  of plants.
• (3) Characteristics are used
• Simple vs. Compound Leaves (Pinnate or Palmate)
• Leaf arrangement on the stem
• (alternate, whorled, or opposite)
• Venation Pattern (parallel, branched)

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Formation of Stems Leaves

• Node where leaves attach to stem
• Internode region between 2 nodes
• Bud undeveloped shoot covered by scales

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Formation of Stems Leaves

• Leaf primordia develop from apical meristem
  as
  
  primary
  shoot
  grows

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Primary Tissues of Leaves

• Epidermis/cuticle (protection desiccation)
• Stomata (tiny pores for gas exchange and
  transpiration)/guard cells
• Mesophyll ground tissue between upper and lower
  epidermis (parenchyma with chloroplasts)
• palisade parenchyma (most photosynthesis)
• spongy parenchyma (gas circulation)

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Structure of Leaves

• Mesophyll Photosynthetic cells
• Air spaces in spongy parenchyma for gaseous
  exchange
• Palisade parenchyma - most sugar

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Internal Structure of a Leaf
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Formation of Leaves

• Monocot leaves
  parallel veined
• Dicot leaves
  net-veined, compound
• Deciduous trees drop
  their leaves in winter
• Conifers, Tropical plants
  remain evergreen

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Structure of Leaves

• Leaf Epidermis
• Waxy cutical protects from drying out resists
  microbial attack.
• Stomata are holes on lower side
• Guard cells
  change shape to
  create stomata
  for water gas
  exchange

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Leaf Hairs

• Increases surface area for water absorption
• Reflect bright sun
• Increases warmth
• Deters predators

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Leaf Shapes

• Broad where water is plentiful
• Narrow where water is scarce

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Cactus Spines

• Modified leaves
• Non-photosynthetic
• For protection

• Where does photosynthesis take place???

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Drip Tips

• Shed heavy rains off easily
• Channels water onto ground below plant

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Introductory Questions 8

• Where is the casparian strip located?
• Why must plants use active transport in order to
  take in ions into the root hair cells?
• Name the two types of cells that make up the
  mesophyll layers in a leaf. What kind of tissue
  (cell types) are they?
• Briefly explain how the stomata open and close.
  Name the ions involved. What color light cause
  the stomata to open?

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Stomata Activity

• Typically open during the day and closed at night
  
• (except in CAM plants) for CO2
• Two Guard Cells that surround the opening change
  their shape when H2O enters and leaves.
  (osmotically)
• Yellow pigments are thought be abundant in the
  guard cells which absorb Blue light (?
  300-400nm).
• Uptake of potassium chloride ions OPENS the
  stomata
• (driven by actively transporting H ions out
  of guard cells)
• Decrease in sucrose concentration CLOSES the
  stomata
• Low CO2 stomata open High CO2 Stomata close

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Stomata Opening and Closing
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Process of Stomata Opening

• ATP Synthase gets activated in guard cells
• H ions are pumped out (malic acid is ionized)
• (H and malate anions are produced)
• H concentration increases outside guard cells
• Charge difference (electrochemical gradient)
  forms across the membrane
• K flow into the guard cells (facilitative
  diffusion) via voltage gated channel once a
  certain voltage is attained
• Chloride ion flow in to electrically neutralize
  the K
• K, Cl-, and malate ions increase the solute
  concentration inside the guard cells (vacuole)
• Water flows in by osmosis, guard cells become
  turgid, cells change their shape, stomata open.

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Stomata Opening Closing
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Closing the Stomata

• Doesnt reverse in the same way
• K decreases throughout the day
• Sucrose increases keeping the solute
  concentration high
• Later in the day, sucrose is converted into
  starch
• Water flows out of the guard cells by osmosis
• Turgidity is lost, Stomata close

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Factors to Consider about Stomata activity

• Amount of CO2 low amounts cause stomata to
  remain open (even at night)
• Amount of Water dehydration drought conditions
  keep the stomata closed
• Abscissic acid levels hormonal control sets the
  ciradian rhythm.

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Transpiration in Plants

• Loss of water by evaporation
• Cuticle helps to reduce this loss (1-3)
• Occurs mostly through open stomata
• Light, higher temperatures, wind, and dry air all
  increase transpiration
• Decreased by high humidity
• Can prevent plants from overheating
• Responsible for water movement in plants (to
  leaves)
• Distributes minerals throughout the plant
• Important part of the hydrologic cycle

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Transpiration in Plants

• Loss of water by evaporation
• Cuticle helps to reduce this loss (1-3)
• Occurs mostly through open stomata
• Light, higher temperatures, wind, and dry air all
  increase transpiration
• Decreased by high humidity
• Can prevent plants from overheating
• Responsible for water movement in plants (to
  leaves)
• Distributes minerals throughout the plant
• Important part of the hydrologic cycle

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Abscission of Leaves

• Why do trees lose their leaves?
• How do the leaves change colors in the fall?

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Abscission of Leaves

• Metabolism photosynthesis slows down
• Water absorption becomes inhibited in the roots
• Transpiration needs to be minimized
• Ethlene levels change
• Essential macromolecules are moved to other parts
  of the plant
• Chloropyll breaks down revealing other pigments
• Carotenoids, Xanthophylls, and Anthocyanins
• (orange) (yellow) (red)
• Abscission zone located near the petiole

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Abscission of Leaves
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Effects of Water