Transport in Plants

• Define Dicotyledonous plant (Dicots):

  A type of plant that produces two seed leaves
• Give examples of dicotyledonous plants:

  • oaks
  • beans
  • spinach
  • roses
• Describe the features of dicotyledonous plants (Dicots);

  • two cotyledons
  • network of veins = starts at the midrib and spreads outwards, for transport and support
  • Vascular bundles = arranged in rings
  • Tap Roots
  • Flowers in multiples of four or five
• Describe the features of monocotyledon plants (Monocots):

  • One cotyledon
  • Parallel veins
  • Vascular bundles = complexly arranged
  • Fibrous root system
  • Flowers in multiples of three
• Give examples of monocotyledon plants (Monocots):

  • grass
  • lilies
  • orchids
  • palms
• Outline reasons why do plants need transport systems?

  • To reduce the diffusion distance
  • Large plants have a small surface area to volume ratio
  • To ensure all cells receive the nutrients they need and remove waste
  • To move water and minerals from the roots up to the leaves
  • To move sugars from the leaves to the rest of the plant
• Name three types of tissue found in plants:

  • Ground
  • Vascular
  • Dermal
• Name the three organs in plants:

  • Roots
  • Stems
  • Leaves
• Name the two vascular tissues in plants:

  • Xylem
  • Phloem
• Name the two dermal tissues found in plants:

  • Epidermis
  • Periderm
• Name the three ground tissues found in plants:

  • Parenchyma
  • Collenchyma
  • Schlerenchyma
• What are found in vascular bundles?

  • Phloem
  • Xylem
• Describe the location of vascular bundles, xylem, and phloem in young roots:

  • Vascular bundles = centre
  • Xylem = centre
  • Phloem = between the arms of the x-shaped xylem
• Describe the location of vascular bundles, xylem, and phloem in stems:

  • Vascular bundles = near the outer edge
  • Xylem = towards the inside
  • Phloem = towards the outside
• Describe the location of vascular bundles, xylem, and phloem in leaves:

  • Vascular bundles = forms midribs and veins
  • Xylem = above the phloem
  • Phloem = below the xylem
• Describe the features of the vascular bundles in young roots:

  Found at the centre

  • x-shaped xylem at the centre = provides strength to withstand forces
  • Phloem = between the arms of the x-shaped xylem
  • outer layer of endodermis = to supply the xylem vessels with water
  • The pericycle : an inner layer of meristem cells
• Define The Pericycle:

  An inner layer of meristem cells in the vascular bundles of roots
• Describe the features of vascular bundles in stems:

  Found near the outer edge

  • Xylem vessels are towards the inside = provides support and flexibility
  • Phloem vessels are towards the outside
  • Cambium : a layer of meristem cells in between the xylem and phloem = produces new xylem and phloem tissues
• Define Cambium:

  A layer of meristem cells in between the xylem and phloem in the vascular bundles of stems
• Describe the features of vascular bundles in the leaves:

  Form the midribs and veins = transport and support

  • xylem = above the phloem
  • phloem = below the xylem
• By which process through the root hair cell does minerals enter the plant?

  Active transport
• Name the three pathways water is taken up by through plants:

  • Apoplast pathway
  • Symplast pathway
  • Vacuolar pathway
• Give two reasons why water is able to move across the root?

  • the cellulose cell wall is permeable
  • there is a difference in water potential between the soil and the root hair cells
• The water potential is higher in the soil than inside the root hair cells, due to the dissolved substances in the cell sap
• Define The Symplast Pathway:

  A method of osmosis where water diffuses across the root hair cells to enter the cytoplasm through the plasma membrane and passes from one cell to the next via plasmodesmata
• Define Plasmodesmata:

  The gaps in the cell wall which connect the cytoplasm of one cell to the next
• Define The Apoplast Pathway:

  Where water moves by mass flow across the root hair cell through intercellular spaces between cellulose molecules in the cell wall
• Define Casparian Strip:

  A waterproof strip surrounding the endodermis of the root.

  It blocks the apoplast pathway forcing water through the symplast pathway
• Explain how water enters the xylem from the endodermis in roots of plants:

  • the xylem vessels have a higher water potential than the cytoplasm of the endodermis
  • ∴ via active transport, dissolved substances, such as mineral ions and salts, move into the xylem to lower the water potential
  • Now the cytoplasm of the endodermis has a higher water potential than the xylem vessels
  • ∴ via osmosis, water moves into the xylem
• Root hair cells have a large surface area to increase the rate of absorption
• Water is absorbed into the plants through the root hair cell by osmosis
• Why is water able to move via osmosis through the cytoplasm of successive cells by the symplast pathway in plants?

  Each successive cell has a cytoplasm with lower water potential than the previous
• Due to what forces of hydrogen bonding in water allows it to move through the cellulose cell wall in the apoplast pathway?

  Cohesive
• Name the pathway that is generally the fastest for the uptake of water in plants?

  The apoplast pathway
• Why is the apoplast pathway generally the fastest way for the uptake of water in plants?

  • there is little resistance to water in the cellulose cell wall
  • the cellulose cell wall is permeable
• Name the type of pathway?

  Blue = symplast pathway

  Purple = apoplast pathway

  
• Meristem cells in plants are used to generate new plant tissues.
• sieve tube elements become elongated and lose most of their cytoplasm.
• Name the different features of a transverse section of a plant stem:

  E= Epidermis

  F= Phloem

  G= Cambium

  H= Xylem

  
• Formula for Stomatal density:

  The number of stomata / 2.5