1. Would warming the Alpine relieve alpine plants from stress?
   No, it would open the space for invaders.
    
2. Which three possibilities do plants have not to become damaged by freezing temperatures.
   Escape, avoidance, and tolerance
    
3. What is the key mechanism adopted by plants that tolerate tissue freezing?
   Intercellular ice formation and controlled cell dehydration
    
4. When is the most critical period for freezing damage in the Alpine?
   Early summer (late spring) and late summer (early autumn)
    
5. (a) Why should plants avoid becoming active during warm spells in winter and (b) how do they achieve this?
   (a) because of the danger of later freezing damage
   (b) by photoperiodism
   
6. (a) How high can bare soil temperatures become in the Alpine and (b) why?
   (a) > 50 °C
   (b) because of direct solar radiation
    
7. How can plants cover patches of hot bare ground?
   By growth during wet/cool periods, and clonal propagation in closed "fronts"
    
8. When is the most critical period for stress induced by high solar radiation?
   After snowmelt
    
9. How do alpine plants cope with enhanced UV-B radiation?
   By UV absorption in the epidermis (e.g. by flavonoids)
    

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29 August 2011
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