Division: Cycadophyta

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Division Cycadophyta

• Cycads are vascular, seed plants that are
  palm-like and are called Sago Palms. The leaves
  are found in a cluster at the tops of the
  trunks. Cycads were first to show true secondary
  growth along plants evolutionary history.
• Be able to recognize the example.

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Division Ginkgophyta

• The Ginkgo or Maidenhair Tree have
  characteristic fan-like leaves. There is only one
  species (from China) that has survived. Only
  males are usually planted in yards because the
  female plants have messy and foul smelling fruit.
  
• Be able to recognize the example in the jar.

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Division Gnetophyta

• The Gnetophytes are unique gymnosperms because
  they have vessel elements. Our example is
  Ephedra or Mormon Tea. It produces a drug called
  ephedrine which raises the heart rate and raises
  blood pressure.
• Be able to recognize the example.

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Division Coniferophyta

• The Conifers, which include pines, spruces,
  hemlocks, and firs, are woody trees or shrubs.
  Most conifers have leaves (megaphylls) that are
  modified into needles or scales.
• Be able to recognize the example.

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Division Coniferophyta

• The Pine Tree contains both male and female
  cones. The pollen (staminate) cones are found
  low in the tree and produce pollen. The ovulate
  cones are high in the tree and produce seeds.

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Male Cones

• The male (staminate) cone consists of protective
  scales called (microsporophylls) that contain
  microsporangia which go through meiosis to
  produce four haploid microspores. These
  microspores will develop into pollen.

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Pollen Grains

• The microspores develop into pollen grains.
  Each pollen grain consists of four cells and a
  pair of wings which are used for dispersal.

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Pollen Grains with Pollen Tube

• Microsporangia produce pollen grains with 4
  cells 2 prothallial cells, 1 generative cell
  (which becomes a sterile cell and a
  spermatogenous cell) and one tube cell. The
  spermatogenous cell produces 2 sperm. Be able to
  recognize the pollen grain, wings, pollen tube,
  and sperm.

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Female Cones

• The female (ovulate) cone consists of protective
  scales called (megasporophylls) that contain
  megasporangia (ovules). The megaspore mother
  cells produce 4 megaspores through the process of
  meiosis. The megaspores are surrounded by a
  nutritional nucellus and a protective seed coat
  called an integument. The megaspores develop
  into a female gametophyte.

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FemaleGametophyte

• At the end of the female gametophyte (n), an
  archegonium (n) which contains two eggs (n) that
  develop. They are surrounded by two layers of
  tissue, the nucellus (2n) and the integument
  (2n). The integument has a channel that allow
  sperm in (a micropyle) and the two layers are
  separted by a pollen chamber.

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Female Cone with Mature Embryo

• The pine embryo consist of an integument, an
  endosperm (food source), cotyledons (food
  source), the hypocotyl (that develops into the
  shoot system), and the radicle (which develops
  into the root system). While developing, one of
  the layers of the integument will become a seed
  coat for the seed.

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Angiosperm

• Be able to recognize the parts of a flower and
  know their functions

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Ovary Position

• When the ovary is embedded below the calyx and
  corolla, it is called epigynous. When the ovary
  is produced on top of they parts, it is called
  hypogynous. When the ovary is centrally
  positioned it is called perigynous. Be able to
  recognize these positions on the drawing.

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Placentation

• The position of the ovary where the ovules
  (seeds) attach is called placentation. There are
  three types of arrangements parietal (top),
  axial (middle), and free central (bottom).
  pigynous. Be able to recognize these positions on
  the drawing.

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Male Gametophyte

• The male gametophyte in flowering plants is a
  pollen grain. They are produced in anthers. The
  anthers have fours chambers that produce quartets
  of pollen. The quartets break into individual
  pollen grains.

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Fertilization

• The majority of plants do not self-fertilize
  themselves. They depend on cross fertilization
  the transfer of pollen from one individual plant
  to another. The most common mechanism to keep
  plants from fertilizing themselves is called are
  produced in self-incompatibility. This works
  similar to an animals immune system where a
  biochemical block prevents the pollen from
  completing its development.

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Germinating Pollen

• Under suitable conditions, the tube cell grows
  into a pollen tube (with a tube nucleus) inside
  the style of another flower. As the tube grows,
  the generative nucleus lags behind and eventually
  produces two sperm.

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Female Gametophyte

• In the female gametophyte, the ovule (surrounded
  by the ovary wall) develops an embryo sac which
  goes through the process of meiosis to create a
  megaspore. The megaspore than goes through
  mitosis twice to produce the four-nucleate stage.

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Female Gametophyte

• The 8-nucleate stage ovary. The emryo is
  located within the embryo sac which contains 3
  antipodals (which disappear after fertilization),
  2 polar nuclei (which join with a sperm that
  produces the endosperm (3n), 2 synergids (which
  disappear), and an egg (which is fertilized).
  Because a sperm joins an egg and another fuses
  with the polar nuceli in flowering plants, it is
  called double fertilization.

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Seeds

• Be able to recognize the parts labeled in the
  diagram to the right.

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Fruit and Seed Dispersal

• Dispersal by Wind
• Many fruits have a wing to allow for dispersal
  and may be carried up to six miles away. Fruits
  that are too large may even be rolled along the
  ground due to the wind. Seeds themselves may be
  winged or small enough to be moved by a slight
  breeze.

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Fruit and Seed Dispersal

• Dispersal by Animal
• Birds, mammals and ants all act as dispersal
  agents. These seed or fruits can be carried and
  dropped, collected and stored, eaten and passed
  through a digestive tract, or stuck in a
  mammalss fur or a birds feathers. Humans are
  the most efficient transporters of fruits and
  seeds.

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Fruit Wall

• The fruit wall is a mature ovary. The skin
  forms the exocarp while the inner boundary around
  the seed(s) forms the endocarp. The are between
  these two areas is called the mesocarp. The
  three regions collectively are called the
  pericarp. In dry fruits, the pericarp is often
  very thin.

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Roots

• Roots are used to anchor the plant in the soil,
  to absorb minerals and water, conduct minerals
  and water and store food.

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Root Tip Regions
Regions Function
Root Cap Protect the apical meristem Perception of Gravity
Apical Meristem Cell Division Production of new cells
Elongation Pushes meristem and root cap through ground
Maturation Development of protoderm, procambium, ground tissue

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Monocot Root
Tissue Origin Function
Epidermis Protoderm Produce root hairs, protection, absorption
Stele Procambium Xylem water movement Phloem food movement Pericycle lateral roots
Cortex Ground Meristem Cortex storage Endodermis regulation of movement Passage Cells lateral movement of water

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Monocot Root

• The three primary meristems give rise to the
  three primary tissues of roots. (protoderm,
  procambium, and the ground meristem). You will
  be beld responsible for the following tissues
  Epidermis, Stele, Xylem, Phloem, Pericycle,
  Cortex, Endodermis, and Passage Cells. You also
  need to know their functions.

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Dicot Root

• A dicot root differs from a monocot root because
  it usually lacks a pith. The three primary
  meristems give rise to the three primary tissues
  of roots. (protoderm, procambium, and the
  ground meristem). You will be beld responsible
  for the following tissues Epidermis, Stele,
  Xylem, Phloem, Pericycle, Cortex, Endodermis, and
  Passage Cells. You also need to know their
  functions.

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Dicot Root
Tissue Origin Function
Epidermis Protoderm Produce root hairs, protection, absorption
Stele Procambium Xylem water movement Phloem food movement Pericycle lateral roots
Cortex Ground Meristem Cortex storage Endodermis regulation of movement Passage Cells lateral movement of water

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Carrot

• A carrot is a modified taproot. Look at a
  longitudinal and cross section of a carrot
  (Daucus) root and be able to identigy the
  following structures Cortex, stele, pericycle
  and lateral roots. The cortex and stele are
  separated by a white line called pericycle.
  Small white lines can be seen going from the
  pericycle to the outside. These are the lateral
  roots.

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Root Hairs

• As the root of a young seedling grows, it
  penetrates the soil. Epidermal cells produce root
  They absorb water and dissolved minerals from
  the soil. The small size and larger number of
  hairs enormously increase the absorptive surface
  of the root and bring it in contact with a large
  volume of soil. For optimum growth, the soil
  should be loosely packed in order to allow for
  gas exchange. Observe the living radish
  seedlings (Rhaphanus) under a dissecting scope.
  The white strings along the roots are the root
  hairs.

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Vascular Bundles

• Vascular tissue running the length of a stem
  composed of primary tissue is called a vascular
  bundle. Vascular bundles are made up of xylem
  (usually seen in red) which face the pith and
  phloem (usually seen in green) which faces the
  cortex. Be able to recognize the difference
  between the two tissues.

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Herbaceous Dicot Stem (Ranunculus)

• In stems of herbaceous plants, there is usually
  only primary tissue. Identify the following
  structures vascular bundles, pith, epidermis,
  fibers, phloem, and xylem. Notice that the
  vascular tissue is found in vascular bundles
  arranged in a ring. usually seen in red) Inside
  the ring is a collection of ground tissue called
  the pith. The fibers stain red and they are
  found on the outer tips of the vascular bundles.
  The fibers add support.

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Herbaceous Monocot Stem

• The tissue arrangement in monocot stems differ
  from that of dicots. The vascular bundles are
  scattered and not found in any set pattern. The
  xylem is usually found toward the center of the
  stem and the phloem is usually facing outward
  within a vascular bundle. Look at the prepared
  slide of a scross section (CS) of the herbaceous
  monocot Zea (corn). The monocot stem does not
  have a true pith.

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Woody Dicot Stem

• Most vascular plants undergo secondary growth,
  which increases girth (width). Two lateral
  meristems are responsible for secondary growth
  the vascular cambium which produces xylem and
  pholem and the cork cambium which produces a
  tough covering called bark. Secondary growth
  occurs in all gymnosperms and most dicot species
  of angiosperms but is rare in monocots. We will
  observe prepared slides of the tree basswood
  (Tilia) to demonstrate the different tissues
  moving from the inside to the outside of the stem.

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Woody Dicot Stem

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Woody Dicot Stem

Tissue Function
Pith Storage
Primary Xylem Moves water and minerals upward
Secondary Xylem Moves water and minerals upward
Vascular Cambium Produces secondary growth
Secondary Phloem Moves nutrients around the plant
Primary Phloem Moves nutrients around the plant
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Woody Dicot Stem(Continued)

Tissue Function
Cortex Storage
Phelloderm Made of parenchyma cells Unknown function
Cork Cambium Produces phelloderm and cork cells
Cork Cells Physical barrier for protection
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Age of a Woody Dicot

• The age of a dicot can be determined by counting
  the number of rings. The rings are made up of
  dead cells called xylem. The type of year
  (rainfall amounts) can be determined by the width
  of the ring.

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Tissues of a Tree Trunk

• By examining a cross section of a mature tree,
  many important regions can be seen by the unaided
  eye. Sapwood and heartwood are made up of
  secondary xylem. Sapwood is younger and function
  for water movement. Heartwood is older, darker
  wood that no longer functions for water movement
  and is used for support.

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Spiral Xylem Vessels

• Conifers have xylem that consist primarily of
  tracheids no fibers or vessel elements. The
  wood tends to be soft and is often called soft
  woods. The woods of woody dicots possess vessels
  elements and tend to be hard and are called hard
  woods. Xylem vessels in woody dicots are spiral
  in shape. These special cells are used for
  carrying water and minerals upward in the stem.
  Be able to recognize a spiral xylem vessel from
  the melon plant Cucurbita.

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The Leaf

• Leaves are the photosynthetic organs of the
  plant. Leaves act as solar panels that capture
  sunlight and convert solar energy into chemical
  energy in the form of sugars using carbons
  dioxide and water. The structure of a leaf can
  actually be divided into three major regions
  the epidermis, the mesophyll, and the veins
  (vascular bundles). Observe the cross section
  (CS) of a leaf. You will be held responsible for
  the following regions, structures and functions.

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The Leaf

Region Structure Function
Epidermis Cuticle Prevents water loss
Epidermis Epidermal Cells Protective layer
Epidermis Guard Cells and Stomates Gas Exchange
Mesophyll Pallisade Layer Photosynthesis
Mesophyll Spongy Layer Photosynthesis and gas exchange
Veins Vascular Bundles Transport
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The Lower Epidermis

• Look at the prepared slide of the lower
  epidermis (Sedum CS) Be able to recognize the
  following structures Guard cells, stomates,
  lower epidermal cells. The epidermal cells will
  look like puzzle pieces. The guard cells are
  regulated by turgor pressure. When they are full,
  the stomates are open. When they are empty, the
  stomates are closed.

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Pine Needles

• Pine trees have adaptations for living in arid
  conditions. In arid regions, one of the largest
  problems faced by plants is water loss through
  the stomates. Pine needles have their stomates
  recessed (sunken) within the surface of the leaf.
  Observe a cross section (CS) of a pine needle
  and be able tecognize the following structures
  guard cells and stomata.

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Minerals and Plant Nutrition

• Plants need certain nutrients to do well. Know
  the following symptoms and their causes.
• Chlorosis lack of N or K
• Deep Green or Purple Pigmentation lack of P or
  N
• Stunted Growth lack of P or N
• Necrosis Lack of K

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Pitcher Plants

• Pitcher plants are found in damp, boggy soils in
  northeast Florida, which are deficient in
  nitrates and phosphates. They capture their prey
  by having their funnel shaped leaves covered with
  nectar glands and down curved teeth. Once the
  insect lands, they move down to a slick area with
  no foothold. The insect falls into the fluid at
  the bottom where it is absorbed.

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Venus Flytrap

• Venus Flytraps are found in damp, boggy soils in
  the Carolinas, which are deficient in nitrate.
  They capture their prey by using their modified
  leaves that contain two lobes. Each lobe has an
  outer area that contains teeth. Each lobe has
  trigger hairs that signal the leaves to close on
  their prey (flies or larger insects smaller
  insects can escape).

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Sundew

• Sundews are found in acid, boggy soils, along
  roadside ditches, which are deficient in
  nitrates. They capture their prey by having
  modified leaves that contain stalked glands or
  tentacles which contain highly viscid mucus.
  They catch only small or very weak prey. Flies
  and ants can escape.

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Gibberellins

• Gibberellic Acid effects germination. Observe
  the seeds that were treated with the hormone and
  compare them to the control seeds. Gibberellic
  acids promote seed germination and plants treated
  with it will grow quicker. This hormone could be
  used to speed up growth in agricultural plants.

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Gibberellins

• Gibberellic Acid effects growth rate. Observe
  the plants that were treated with the hormone and
  compare them to the control plants. Gibberellic
  acids promote stem elongation and plants treated
  with it will grow longer. This hormone is used
  to produce flower shoots but can cause problems
  if the stems grow too quickly.

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Phototropism

• Some researchers believe it is the tip of the
  plant. Observe the plant that was placed next to
  a light. Auxin is the hormone that is thought to
  be responsible for the plant bending toward the
  light. It is the stem that is actually
  bending. The plant actually doesnt bend. The
  cells away from the light are affected more by
  auxin and elongate faster which bends the plant
  toward the light.

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Gravitropism

• Shoots display a negative gravitropism. Observe
  the plant that was placed on its side. Plants
  may tell up from down by the settling of
  Statoliths (plastids with heavy starch grains).
  Auxin is the hormone that is though to be
  responsible for the plant bending upward. The
  stem actually doesnt bend. The cells on the
  bottom of the plant are more affected than the
  upper cells and elongate faster which bends the
  plant upward.