ANIM2501 Lecture Notes - Lecture 4: Drug Tolerance, Germination, Astrebla
Plant growth adaptations
1. Adaptation to Drought:
- Dormancy and germination mechanisms in arid areas- ensures long term survival of seed in
soil for future regeneration. (Remain dormant till got right conditions)
- Morphological adaptation to moisture stress. (E.g. Deep roots to get moisture from a larger
area of soil)
- Physiological tolerance of moisture stress (e.g. Ability to grow at low leaf tissue water
potentials)
- Some species long lived.
2. Adaptation to low fertility:
- Most native species tolerant of low fertility.
3. Adaptation to regular grazing:
- Tolerance to grazing
Effects of grazing:
- Historically in Australia, light grazing with regular burning. Attracts animals because got new
growth which is highly nutritious.
- Since Europeans (brought in domestic animals), less grazing pressures, less frequent
burnings, changes in composition in native pasture communities.
- Rangelands vary in their response to grazing.
Grazing effects on ecology of native pastures:
- Native 3Ps decrease under grazing
- Less palatable perennial and annual grasses increase under grazing.
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Document Summary
Dormancy and germination mechanisms in arid areas- ensures long term survival of seed in soil for future regeneration. (remain dormant till got right conditions) Deep roots to get moisture from a larger area of soil) Physiological tolerance of moisture stress (e. g. ability to grow at low leaf tissue water potentials) Most native species tolerant of low fertility. Historically in australia, light grazing with regular burning. Attracts animals because got new growth which is highly nutritious. Since europeans (brought in domestic animals), less grazing pressures, less frequent burnings, changes in composition in native pasture communities. Rangelands vary in their response to grazing. Less palatable perennial and annual grasses increase under grazing. If graze column 1, column 2 will decrease and column will increase. Patch grazing: if they keep grazing, some of the grasses will disappear. Water and shade is available ((mitchell grass no shade?) Cattle less selective than sheep and eat taller species.
