Chapter 24: Kingdom Plantae

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Chapter 24 Kingdom Plantae

• Leaving Certificate Biology
• Higher Level

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Structure of Flowering Plant

• The flowering plant (also called angiosperm) is
  an example of a living organism that has
  organisational complexity
• Root
• Stem
• Leaf
• Flower
• Seed
• Vascular (transport) structures

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Structure of Flowering Plant
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Structure of Flowering Plant

• Function of root and shoot system
• Roots
• Anchorage
• Absorb water and minerals
• Transport water and minerals up plant
• Some root store food
• Shoot
• Transport water, minerals, food
• Sexual reproduction
• Photosynthesis

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Roots

• Types
• Tap roots main root that originates from the
  radicle at germination
• Lateral emerge from the primary root
• Fibrous roots equal size roots that emerge from
  the stem common in monocotyledonous plants,
  e.g. grass

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Root Zonation

• Protection root cap protects growing tip
• Meristematic tissue region of high cell
  production (mitosis) and growth
• Elongation new cells formed within the meristem
  then elongate under the influence of growth
  regulators
• Differentiation elongated cells differentiate
  into specialised cells (dermal, ground, vascular)

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Meristem

• The meristem is the region of the shoot tip or
  root tip where there is rapid mitosis occurring
  and is responsible for the growth of the plant
• The meristematic regions are present in the root
  and shoot tips and in peripheral regions such as
  in the axillary buds, leaves and fruits

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Stems

• The stem supports the plant and carries the
  leaves, flowers and fruits of the flowering plant
• Depending on the plant species the stem is either
  herbaceous (soft, green stem) or woody (hard,
  usually brown stem)
• The leaves and branches emerge from points on the
  stem called nodes whereas the section in
  between the nodes is called the internode
• Woody stems also have lenticels present on their
  surface which are responsible for gas exchange

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Functions of the Stem

• Support
• Transport of water, minerals and food
• Herbaceous stems carry out photosynthesis
• Some store food

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Leaf

• The leaf is an organ of food production the
  site of photosynthesis
• The leaf of a plant is attached to the stem or
  branch by the petiole located at the node
• The leaf is a flattened structure (blade/lamina)
  designed to capture sunlight
• The leaf has a midrib and veins which are
  continuations of the petiole and which contain
  vascular tissues

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Leaf Venation

• Leaf venation depends son the plant species and
  can be either parallel or net/reticulate
• Parallel veins run parallel to each other and
  are most common in monocotyledonous plants such
  as grasses
• Reticulate veins form a network of veins by
  branching out filling the leaf structure and are
  most common in dicotyledonous plants such as
  horse chestnut (see leaf structure on previous
  slide)

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Function of the Leaf

• Photosynthesis and food production
• Gas exchange
• Transpiration process of losing water
• Food storage

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Flower Structure
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Function of the Flower

• The flower function in sexual reproduction by
  attracting insects (presence of nectar) and
  animals (seed and fruit formation after
  fertilisation)

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Types of Plant Tissue

• Dermal
• Functions in protection by having a thick cuticle
• Also has stomata and controls gas exchange
• Also has root hairs and controls absorption of
  water and minerals
• Ground tissue
• Is responsible for photosynthesis, food storage
  and gives strength and support to the plant
• Vascular tissue
• Xylem transports water and minerals
• Phloem transports food

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Xylem

• Xylem is a vascular tissue made up of two
  different types of cell
• Xylem tracheids
• Xylem vessels
• Tracheids long, tapered, hollow and dead cells
  whose walls contain pits that allow water
  movement
• Vessels they are strong (supported by lignin),
  long, hollow, dead, tubular cells with their end
  walls broken down to form a continuous tube
  throughout the tissue

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Tracheid
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Vessels
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Phloem

• Phloem is a transport system running alongside
  xylem that allows products of photosynthesis to
  be redistributed by the plant
• Phloem consists of sieve tubes that transport the
  sugars and companion cells that help in
  transferring the sugars to the sieve tubes

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Structure of Phloem
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Xylem versus Phloem
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Transverse Section of the Root
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Structure of Leaf
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Monocots versus Dicots

• Monocotyledonous plants
• 1 cotyledon (storage leaf) in seed
• Mostly herbaceous plants soft, green stem
• Long, narrow leaf with parallel venation
• Vascular bundles arranged randomly in stem
• Petals, leaves arranged in 3s or multiples of 3
• Dicotyledonous plants
• 2 cotyledons (storage leaves) in seed
• Herbaceous or woody
• Broad leaves with network or reticulate venation
• Vascular bundles arranged in ring in stem
• Petals, leaves arranged in 4s or 5s or multiples
  of 4s or 5s