Vegetative organs of flower plants

• Vegetative organs of a flowering plant

  • Roots
  • Stems
  • Leaves
• Roots


  • Anchor the plant in the ground
  • Absorb water and dissolved nutrients from the soil
  • Store extra sugars made during photosynthesis
• Anatomy of a root

  1. Meristematic region

  2. Elongation region

  3. Maturation region
• The stem contains the main portion of the plant's vascular system, which is a continuous pathway from the roots, through the stem, to the leaves
• Vascular system


  Transports water and dissolved minerals from the roots to the leaves (through the xylem) and food (mainly glucose) from the leaves to the roots (through the phloem)
• Photosynthesis


  1. Light (light-dependent) reactions

  2. Dark (light-independent) reactions (also called the Calvin cycle)
• The light and dark reactions of photosynthesis are related as shown in the diagram
• Light (light-dependent) reactions


  Occur in the thylakoid membrane of the chloroplast, require light energy and produce ATP, NADPH, and O₂ (as waste)
• Dark (light-independent) reactions


  Occur in the stroma of the chloroplast, do not require light but require chemical energy in the form of ATP and NADPH (produced during the light reactions) as well as CO₂
• The Ruben and Kamen experiment used radioactive isotopes of oxygen to prove that the oxygen produced during photosynthesis comes from water, not CO₂
• Photosynthesis is the process in which green plants capture the sun's energy and convert it into chemical energy stored within the bonds of carbohydrates (most commonly glucose)
• Chloroplast


  The oval double-membrane organelle found in cells of plants and green algae where photosynthesis takes place
• Parts of leaf structure

  • Cuticle
  • Upper epidermis
  • Palisade mesophyll
  • Spongy mesophyll
  • Lower epidermis
  • Guard cells
  • Stomata
• Electromagnetic (EM) spectrum


  The entire range of EM radiation that exists, from gamma rays to radio waves
• Visible light


  The portion of the EM spectrum that can be seen by the human eye, ranging from 380-760 nm
• Visible light


  • Behaves as vibrating bundles of energy called photons
  • Acts as both a wave and a particle
• When visible (white) light encounters a green leaf

  The leaf absorbs all parts of the light spectrum except green, and reflects the green part
• Pigment


  A molecule that differentially absorbs and reflects various wavelengths (colours) of light
• Chlorophyll


  The dominant pigment in leaves, a family of pigments with a similar chemical structure including chlorophyll a and chlorophyll b
• Chlorophyll


  • Has a complex porphyrin ring with a central Mg atom, and a long hydrocarbon chain
  • The R group extending from the porphyrin ring differs between chlorophyll a and chlorophyll b