2. Adaptations of Plants to High Elevation Flashcards
What does “alpine” mean?
“white” or ”snow-covered” (latin)
“alp”, “alb”, “alpo” (indo-germanic, basques)
What is the definition of alpine vegetation?
Any low stature vegetation above the climatic tree-line
worldwide
What is the definition of alpine plant?
Plants that are almost exclusively found in the alpine zone
What are the altitudinal vegetation zone?
Lowland, Submontane: forest and bush organized by species composition
Montane: montane forest >5 m high
Upper Montane: montane forest 2-5 m high
TREELINE
Subalpine: shrubs and trees 0.5 - 2 m high
Alpine: herbs, shrubs, <0.5 m high, rosette plants
UPPER LIMIT OF VASCULAR PLANTS
Nival and subnival: Only cryptograms
What are vascular plants?
- Plants that distribute water and minerals throughout their body
- Have true roots, leaves and stem
- Can acquire larger size than non-vascular plants
ex. Examples of life-forms: shrubs, grasses, forbs, ferns (mostly perennial)
What is the highest known occurrence of vascular plants?
6400 m, collected during 1935 and 1952 Mount Everest expeditions
(Saussurea gnaphalodes, Lepidostemon everestianus)
Plants derive energy from what?
Photosynthesis
How does photosynthesis work?
carbon dioxide + water —light–> sugar + oxygen
- Green plants use light energy to convert carbon dioxide and water into sugar and oxygen.
- Sugars produced in photosynthesis are converted into biomolecules that make up the dry weight (biomass) of a plant.
What are chloroplasts (in cells)?
sites of photosynthesis, contain chlorophyll - a pigment that is essential to photosynthesis. Located in leaves (and stems) of plants.
What specific light wavelength does photosynthesis occur at?
400-700 nm (visible light)
Ultraviolet light, specifically UV-B (280-320nm), penetrates through the stratosphere and has what kind of effect on photosynthesis?
A damaging effect: its higher energy content can destroy biological tissue and DNA.
What is high UV-B irradiation?
- UV-B intensity decreases with latitude
- UV-B intensity increases with altitude (but clouds can counteract this)
The alpine environment does not exist but some frequent features are…
- High UV radiation
- Reduced mean temperature (low-temperature extremes)
- High-temperature fluctuations
- Windy
- Short growing season
- Precipitation often as snow
- Shallow soils
- Low water and nutrient avaliability
What plants need: Liquid water
Availability at high altitudes: ?
Limiting (not readily available)
What plants need: Light
Availability at high altitudes: ?
Limiting (à long snow cover, clouds)
What plants need: Warmth
Availability at high altitudes: ?
Limiting
What plants need: Nutrients
Availability at high altitudes: ?
Limiting
What plants need: p(CO2) partial pressure of cardon dioxide
Availability at high altitudes: ?
Decreases (but higher than historically)
à Global warming, Körner (2002)
What is a limiting factor?
An environmental factor that restraints abundance, growth and
dispersal in organisms
What is an adaptation to high UV-B irradiation
- Dense hairiness
- Thick epidermis (outer leaf layer) with beneficial compounds
- Some alpine plants build anthocyanins to avoid damage by UV-B light
- : Epidermis (outer leaf layer) absorbs a lot of UV light in alpine plants. : Effect possibly due to extractable compounds in epidermis (Extract contained flavonoids, lipids, cuticular waxes)
Example of a species with dense hairness?
Leontopodium nivale
What are anthocyanins?
water soluble pigments (red, purple, blue)
Example of a species that uses anthocyanins?
Oxyria digyna, Mountain sorrel
Adaptation to cold temperature?
- Alpine plants have a flexible photosynthesis: it operates near maximum over a wide temperature range.
- Photosynthesis is mostly limited by low light (quantum flux density) in high-altitude conditions, not temperature!
