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.
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.
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
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
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.
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.
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