The Plant Kingdom

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The Plant Kingdom

• The Plant Kingdom An Introduction - Learning
  Activity

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Plant ClassificationBryophytes

• Mosses have no true roots, only structures
  similar to root hairs called rhizoids.

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More on bryophytes

• Mosses have simple leaves and stems.

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Liverworts are bryophytes

• Liverworts consist of a flattened thallus.

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Bryophytes

• Maximum height is 0.5 ,meters
• Reproductive structures Spores are produced in a
  capsule. The capsule develops at the end of a
  stalk

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Life Cycle of a Moss animation
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Filicinophytes

• Ferns have no true roots, leaves, and short
  woody stems. The leaves are usually curled up in
  buds and are often pinnate, ( divided up into
  pairs of leaflets).

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Pinnate leaves

• There is a main nerve, called midrib, from which
  the other nerves derive Cell Cycle Cancer
  Animation
• Life cycle Flifecycle2

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Filicinophytes / Ferns

• Maximum height is 15 meters
• Spores are produced in sporangia, usually on the
  underside of leaves
• All have vascular roots, leaves non-woody
  stems.

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Coniferophytesconifers

• Conifers are shrubs or trees with roots, leaves
  and woody stems. The leaves are often narrow
  with a thick waxy cuticle

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Produce cones for reproduction
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conifers

• Maximum height is 100 meters
• Seeds are produced. The seeds develop from ovules
  on the surface of the scales of female cones.
  Male cones produce pollen

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Angiospermophytesflowering plants

• Flowering plants are very variable but usually
  have roots, leaves and stems. The stems of
  flowering plants that develop into shrubs and
  trees are woody.

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angiosperms

• Maximum height is 100 meters. Seed are produced.
  The seeds develop from ovules inside ovaries.
  The ovaries are part of flowers. Fruits develop
  from the ovaries, to disperse the seed.

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Flowers. Pistil is female part and stamen is male

• Animations
• Animations

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Plants adapt to where they grow

• Xerophytes - plants that are adapted to grow in
  very dry habitats.
• Spines instead of leaves, to reduce transpiration
• Thick stems containing water storage tissue
• Very thick waxy cuticle covering stem, reducing
  water loss

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• Vertical stems to absorb sunlight early and late
  in the day but not at midday when the light is
  most intense
• Very wide spreading network of shallow roots to
  absorb water after rains
• CAM physiology, which involves opening stomata
  during the cool nights instead of during intense
  day heat

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Thick leaves and cuticle
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Hydrophyteswater plants

• Air space in the leaf to provide buoyancy
• Stomata in the upper epidermis of leaf is in
  contact with the air
• Waxy cuticle on the upper surface but not on
  bottom surface
• Small amounts of xylem in stems and leaves

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Leaves

• Tissues of leaves and their function

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• Palisade mesophyll consists of densely packed
  cylindrical cells with many chloroplast. This is
  the main photosynthetic tissue and is positioned
  near the upper surface where the light intensity
  is highest

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• Upper epidermis a continuous layer of cells
  covered by a thick waxy cuticle. Prevents water
  loss from the upper surface even when heated by
  sunlight. Lower epidermis is in a cooler
  position and has a less thick waxy covering

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• Upper epidermis a continuous layer of cells
  covered by a thick waxy cuticle. Prevents water
  loss from the upper surface even when heated by
  sunlight. Lower epidermis is in a cooler
  position and has a less thick waxy covering

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• Note stomata on epidermis. The stomata is a pore
  that allow carbon dioxide for photosynthesis to
  diffuse in and oxygen out

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• Xylem brings water to replace losses due to
  transpiration

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• Phloem transports products of photosynthesis
  out of leaf.
• Both xylem and phloem are called the vascular
  system of plants. The vein is centrally located
  to be close to all cells.

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phloem
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Transport in phloem

• Phloem is located inside leaves. Used to
  transport sugars, amino acids, and other organic
  compounds from photosynthesis.
• Structures called sieve tubes do the
  transporting.
• This is an active process requiring ATP
• High concentration in sieve tubes of solute cause
  water to move in by osmosis

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• This creates a high enough pressure for movement
  where ever the plant needs these products.
• The transport of any biochemical (includes
  sprayed on chemicals) in phloem is called
  translocation.
• Sucrose Transport animation
• Sugar Transport in Plants
• Tutorial 36.1 The Pressure Flow Model

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Transpiration

• Flow of water from the roots, through the stems
  to the leaves of plants (transpiration)
• Starts with evaporation of water from the cell
  walls of spongy mesophyll.
• Water is replaced with water from the xylem

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Xylem and transport of water

• Google Image Result for http//www.phschool.com/sc
  ience/biology_place/labbench/lab9/images/xylem.gif
  
• KScience Transpiration
• Animations

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Structure of xylem
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Factors which affect transpiration

• Light closed guard cells in stomata in darkness
• Temperature high temp increase rate of diffusion
  through air spaces in spongy mesophyll
• Humidity movement by osmosis requires water
  potential gradient. Low humidity increases
  transpiration
• Wind blows saturated air away from leaf thus
  increasing transpiration

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Food storage in plants

• The excess products of photosynthesis may be
  stored in storage area called tubers.

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Monocot and Dicot
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True dicots vs monocots ( animation)
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• Plants Plant Organs - Stems

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Function of stem

• Connects roots, leaves, and flowers
• Transport materials between them using xylem and
  phloem
• Support the aerial parts (especially xylem in
  woody plants)
• Pith and cortex provide cell turgor

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• Plants Plant Organs - Stems

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Monocot / dicot stems

• Stem organization

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Monocot stems

• In most monocots, the vascular bundles arc
  scattered throughout thc ground tissue.

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Dicot stem

• The stems of most dicots have vascular bundles
  arranged as a ring that divides the ground tissue
  into the outer cortex and inner pith.

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Roots dicots

• In most dicots (and in most seed plants) the root
  develops from the lower end of the embryo, from a
  region known as the radicle. The radicle gives
  rise to an apical meristem which continues to
  produce root tissue for much of the plant's life.

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Monocot root

• By contrast, the radicle aborts in monocots, and
  new roots arise adventitiously from nodes in the
  stem. These roots may be called prop roots when
  they are clustered near the bottom of the stem.

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Roots
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• Roots absorb mineral ions and water from the soil
• Anchor the plant and are sometimes used for food
  storage
• Plants Transport and Nutrition - Water Movement

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Mineral uptake by roots

• Plants absorb potassium, nitrate and other
  mineral ions
• Concentration is lower than inside roots
• active transport
• Root hairs provide surface area for ion uptake

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Water uptake by roots

• High solute concentration in roots therefore
  water moves in to root from soil.
• Two paths
• Symplastic movement from cell to cell through the
  cytoplasm
• Movement by capillary action through cortex cell
  walls called apoplastic

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Nutrients Plants Transport and Nutrition
Nutrients (animation)
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Nutrients Plants Transport and Nutrition
Nutrients (animation)
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Flowers

• Monocots have their flower parts in threes or
  multiples of three

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• Dicots have their flower parts in fours (or
  multiples) or fives (or multiples).

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Reproduction in flowering plants

• Egg and pollen formation and fertilization
  animation
• Life cycle of cherry (Prunus)

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• The transfer of pollen from the anther to the
  female stigma is termed pollination. This is
  accomplished by a variety of methods. Flower
  color is thought to indicate the nature of
  pollinator red petals are thought to attract
  birds, yellow for bees, and white for moths. Wind
  pollinated flowers have reduced petals, such as
  oaks and grasses.

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Double Fertilization

• The process of pollination being accomplished,
  the pollen tube grows through the stigma and
  style toward the ovules in the ovary
• Life cycle of a lily ( animation )
• Tutorial 39.1 Double Fertilization

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Pollen tube
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• Monocot seeds will not separate into two Halves.
  Instead, the food is stored around the embryo.
• have one seed leaf which is generally long and
  thin
• Rice wheat corn

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Dicots

• has two halves.
• called cotyledons.
• food stored in the fleshy seed leaves to nourish
  the new plant until its roots and true leaves are
  ready. first two seed leaves look quite different
  from the adult leaves, which will develop later.

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Seeds
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Seeds in a Pod,
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germination

• Requirements proper
• temperature.
• water
• Water is always needed to allow vigorous
  metabolism to begin. It is also sometimes needed
  to leach away a germination inhibitor within the
  seed. This is especially common among desert
  annuals. The inhibitor is often abscisic acid
  (ABA).
• oxygen
• a preceding period of dormancy (often).

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Germination in Dicots

• The primary root emerges through the seed coats
  while the seed is still buried in the soil.
• The hypocotyl emerges from the seed coats and
  pushes its way up through the soil. It is bent in
  a hairpin shape the hypocotyl arch as it
  grows up. The two cotyledons protect the epicotyl
  structures the plumule from mechanical
  damage.

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• Once the hypocotyl arch emerges from the soil, it
  straightens out. This response is triggered by
  light.
• The cotyledons spread apart exposing the
• epicotyl, consisting of
• two primary leaves and the
• apical meristem
• Plant development ( animation)

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Germination in Monocots

• the primary root pierces the seed (and fruit)
  coverings and grows down
• the primary leaf of the plant grows up. It is
  protected as it pushes up through the soil by the
  coleoptile a hollow, cylindrical structure.
• Once the seedling has grown above the surface,
  the coleoptile stops growing and
• the primary leaf pierces it.

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Germination in Monocots

• the primary root pierces the seed (and fruit)
  coverings and grows down
• the primary leaf of the plant grows up. It is
  protected as it pushes up through the soil by the
  coleoptile a hollow, cylindrical structure.
• Once the seedling has grown above the surface,
  the coleoptile stops growing and
• the primary leaf pierces it.

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Metabolic events of seed germination

• Water first causes re hydration which allows for
  seed to become metabolically active.
• Growth hormone called gibberellins is produced in
  the cotyledons
• This stimulates the production of amylase which
  converts the stored starch into maltose

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• Maltose is converted into glucose needed for
  cellular respiration
• Leaves appear above ground and photosynthesis
  begins.

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Review of seed/fruits/germination

• Life  eLearning

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Hormones

• General Human Biology

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• 1. Auxins stimulate cell elongation in shoot
  tips, embryos, young leaves, flowers, fruits, and
  pollen. Auxins are more concentrated at the main
  shoot tip, which blocks growth of lateral
  buds(apical dominance).

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• 2. Gibberellins stimulate cell division and
  elongation but act more slowly than auxins.
• 3. Cytokinins stimulate mitosis in actively
  developing plant parts.
• 4. Ethylene speeds ripening
• 5. Abscisic acid inhibits the growth-inducing
  effects of other hormones.

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Plant stimuli

• General Human Biology

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Plant response to stimuli

• 1.A tropism is a growth response toward or away
  from an environmental stimulus, usually caused
  when different parts of an organ or structure
  grow at different rates.
• 2. In phototropism, light sends auxin to the
  shaded portion of the plant, stimulating growth
  towards the light.

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• 3. Shoot growth is a negative gravitropism, and
  root growth is a positive gravitropism. The
  positions of amyoplasts in cells apparently help
  plants detect gravity.
• 4.. Thigmotropism is a response to touch.

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• 5. Nastic movements are not oriented toward a
  stimulus. Thigmonatsy is response to contact.
  Nastic response to light and dark is photonasty,
  caused by osmotic changes that differently alter
  cell volume.

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Growth

• Tutorial 35.1 Secondary Growth The Vascular
  Cambium

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Regulation of plant growth

• Tutorial 38.1 Tropisms
• Tutorial 38.2 Went's Experiment
• Tutorial 38.3 Auxin Affects Cell Walls
• Plant response to environmentTutorial 40.1
  Signaling between Plants and Pathogens

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Review of topic

• General Human Biology