Flowering Plants

• Plants grow by meristems. A Meristem is a region where active cell division occurs allowing growth. They are located in shoot tips and root tips and auxiliary buds.
• Dermal tissue in plants is the outer covering. It functions in protection, gas exchange and the absorption of water and minerals.
• Ground tissue in plants functions in photosynthesis, storage or support.
• Vascular tissue is composed of xylem (water transport) and phloem (Food transport).
• Monocotyledon plants only have one cotyledon in their seed e.g. grass, wheat, barley, oats
• Dicotyledons have two cotyledons in their seeds e.g. sunflower, peas, broad beans
• Roots anchor plants and absorb water and minerals from the soil E.g. Nitrogen and phosphorus
• Stems support the aerial parts of the plants. They transport water and minerals up to the leaves and flowers.
• Lenticels are openings or apertures on the stem. The function of these openings is for gaseous exchange.
• Xylem is composed of complex tissue. It consists of xylem vessels and xylem tracheids.
• Xylem vessels are cylindrical shaped cells staked end to end. They have a thick cell wall strengthened by lignin and a narrow lumen. They also have pits to allow water to pass through.
• Xylem tracheids are not as efficient at transporting water as vessels because they have tapered ends.
• Cambium is a meristem tissue where cell division occurs by mitosis. Cambium is located inside the vascular bundles of dicot stems. Cambium leads to new xylem and phloem being laid down each year. The bark of a tree is dead xylem which has accumulated over many years.
• Unlike xylem, phloem is a living tissue. It is also complex. It is composed of sieve tubes and companion cells.
• The end walls of phloem have pores to allow food to pass from one cell to another. The sieve tube has very few organelles allowing sugars to flow easily.
• External structure of a flowering plant:

  A) terminal bud

  B) axiliary bud

  C) leaf

  D) shoot meristem

  E) shoot system

  F) node

  G) vascular tissue

  H) root hair

  I) root tip

  J) root cap

  K) root meristem

  L) root system

  
• Root systems:

  A) tap roots

  B) fibrous roots

  
• TS of a root:

  A) root hair

  B) epidermis

  C) ground tissue

  D) xylem

  E) phloem

  
• Structure of a stem:

  A) apical bud

  B) node

  C) lenticel

  D) internode

  E) bud scale

  F) vascular bundle

  G) pith

  
• Seed structure:

  A) seed coat

  B) plumule

  C) radicle

  D) epicotyl

  E) hypocotyl

  F) cotyledons