BIOL 1070 Lecture Notes - Radiant Energy, Permafrost, Photosynthesis

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26 Nov 2011
of 2
Mon, NOVEMBER 14th!
What abiotic factors challenge Arctic plants???
Abiotic Factors & Impact/ challenge:
Terrain (tough, cold wind), Availability of Light (short days not much light, or long days
of light) Permafrost (difficult for plants to survive, limits access to resources
(nutrients/moisture), Exposure to harsh winds (physical pressure on leaves, hard to deal
with, high wind desiccation, wind damage) , Air Temp (tissue Damadge due to temp
extremes), Snow Cover (Shelter from the wind and insulates temp extremes),
precipitations/moisture (lack of moisture below freezing temps; air is very dry at low
temps) Soil nutrients ( restricted nutrient availability; slow microbial decompostition and
mineralization rates of organic matter constrained by low temps), Geo-physical (scouring
by ice, snow pack, spring/summer erosion)
What are the adaptations of arctic plants:
Hairy leaves and stem; small size ; small leaves
Increased anoxia tolerance; small size; shorter life cycle
Deep pigmentation (absorb more radiant energy); increased respiration; long life cycles;
increased importance of vegetative reproduction
Thick waxy cuticle on leaves
Freeze tolerance (-30 – -196Celsius); propylene glycol (ANTIFREEZE) in cells; call wall
Vegetative reproduction, can recover quickly even If many plants damaged.
Morphological adaptations for growing in specialized habitats like rock; use of sheltered
microhabitats and south-facing slopes
Different strategies for nutrient uptake, and utilization of different sources of nitrogen;
recycling mechanisms; mycorrhical partners
ICLICKER: ANS:D) plant growth and net photosynthesis increases with an experimental
Why do lichens thrive in the arctic?
Grow on bare rock
No roots, rhizines for attaching to substrate
Can extract moisture and nutrients from the air
Tolerant to freezing
Desiccation tolerant
Fungal partner can utilize low amount of nitrogen
Algal partner can photosynthesize at low light leves
Can be dormant for long periods of time
Asexual reproduction
What is a lichen? Iclicker 2
How do herbicides reduce lichen biomass ??
- kill lichens