Control of Tundra Plant Allocation Patterns and Growth 



149 



TABLE 5-1 Biomass and Carbohydrate Composition of V2 

 tillers of Dupontia fisheri 



• Lewis and Tieszen (unpubl.). 



tEstimated as 30 to 40% of total biomass at peak season (from McCown 1978); seasonal 

 changes assumed negligible with senescence equal to production. 



t McCown (1978). 



** Estimated as equal to early season. 

 tt By subtraction. 



between 20 and 40% of the total dry weight (Shaver and Billings 1976, 

 McCown 1978, McKendrick et al. 1978) (Table 5-1, Figure 5-5). High 

 TNC levels are typical of arctic and alpine species (Russell 1940, Mooney 

 and Billings 1960, Warren Wilson 1966a, Fonda and Bliss 1966, but see 

 Payton and Brasch 1978). This raises the question of whether tundra 

 plants have a carbon/energy surplus or whether there is strong selection 

 to maintain high TNC levels in spite of high growth demands for TNC. 

 Russell (1940), Warren Wilson (1966a) and Haag (1974) concluded that 

 low temperature somehow prevented carbohydrate use in growth and 

 respiration, resulting in large sugar accumulations. We suggest that in- 

 adequate nutrient supply is a major factor limiting use of carbohydrates 

 in growth. Ahhough there is considerable interhabitat variation in pro- 

 duction along a gradient of nutrient availability at the Biome research 



