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2013-11-14 01:29:14

plants scerophyll
Show Answers:

  1. What is a xeromorph?
    • Plants that are able to survive in dry and water stressed environments are known as xeromorphs
    • These plants thrive in dry , fire frequent areas.
  2. What is a succulent?
    • Succulents are plants like cacti that have reduced leaves and fleshy structures filled with sap.
    • They have photosynthetic stems
    • Chenopodia : that have salt bladders and grey in colour to reflect the sun are an example.
  3. What is a sclerophyll
    • more common than succulents 
    • they have woody structural tissue 
    • small leaves with short inter nodes
    • reduced S.A to volume ration
    • have primary and secondary cells 
    • leaf hairs and sunken stomata
    • spinifex is an example
  4. Why did scelorophyll evolve and why is phosphorus important?
    • Sclerophylly evolved due to low phosphorus levels. One can test this by measuring varying phosphorus levels in rain forest where water is constant. plants will still vary 
    • Phosphorus is important for cell growth and metabolism,ATP etc
  5. What are the two types of adaptation of xeromorphs to fire?
    • Tolerates fire : has protective features that allow it to survive fire
    • Killed by fire : killed by fire but seed lives.
  6. Explain Re sprouting
    • In this technique tree survives fire due to thick bark 
    • Dormant buds : change in hormones prompts new shoot growth (ariel epicormic)
    • Underground Buds : swelling at the base of the tree rich in lignotubers
    • Rhizomes : underground stems shoot out
    • Suckering :if the above ground is killed it puts up shoots from the root.
  7. Regeneration/ when you are killed by fire what happens?
    • Seeds are protected due to woody structure i.e Hakea , Eucalyptus
    • Seeds with impervious coat: Normally water is required for germination , when fire occurs seed cracks , water penetrates - germination
    • Seeds with funicle :ants eat eliasome and bury seed until fire when they germinate
    • Smoke compounds act as a hormone to stimulate burning