Reproduction and vegetative

• Asexual reproduction


  The production of new individuals from a single organism without the fusion of gametes
• Asexual reproduction


  • All the individuals formed in this way form a clone of genetically identical organisms
  • There may be some limited variation amongst the organisms in a clone that is caused by random mutation
• Binary fusion


  A single organism becomes two independent organisms
• Budding


  1. A new plant develops from an outgrowth known as the bud

  2. Cell division at one particular site
• Asexual spore formation


  1. Spores are asexual reproduction bodies that are surrounded by a hard protide cover to withstand unfavourable conditions

  2. Under favourable conditions, the spores germinate and grow into new plants
• Fragmentation


  1. A new plant is produced from a portion of the parent plant

  2. Each section or a part of the plants develop into a mature, fully grown individual
• Vegetative propagation


  • A form of asexual reproduction of a plant
  • Only one plant is involved and the offspring is a result of one parent
  • The new plant is genetically identical to the parent

  
• Principles of cutting


  1. Stem with at least one node or bud is cut

  2. Stem then is covered in a thin layer of soil

  3. New shoots grow from buds and a new underground stem (rhizome) is formed
• Principles of tissue culture

  1. Removal of meristematic cells from the plant (explant)

  2. Explant is immersed in a well-aerated solution containing a balance of auxin and cytokinin to stimulate cell growth and division and nutrients (sucrose, and inorganic ions K, Mg and nitrates) and is sterile to prevent fungi and bacteria

  3. Undifferentiated cells in the explants divide by mitosis to produce callus

  4. A callus is placed in agar jelly with nutrients to produce root and shoot

  5. When the plant is large enough it's placed in sterile soil

  
• Importance of vegetative propagation

  • New plants are easily established where these are not viable and do not grow
  • Gives a reliable supply because of the uniform appearance
  • Plants are genetically identical
  • Plants are uniform size which helps with harvesting and packaging
  • Used to generate large numbers of new, genetically identical plants

  
• Asexual or clonal reproduction is expected to reduce genotypic diversity and slow down adaptation through reduced selection efficacy, yet the evolutionary consequences of clonal reproduction remain unclear for many natural populations
• Asexual reproduction in plants

  • Ginger
  • Meristem
  • Hormone stimulation

  
• Marginal utility


  The additional utility (satisfaction) gained from the consumption of an additional product
• If you add up marginal utility for each unit you get total utility
• Mr. Manning: 'Plants are amazing because they provide us with oxygen to breathe, food to eat, and materials for clothing and shelter. They also make our environment beautiful. Let's appreciate and take care of plants because they are an essential part of our lives and our planet.'