Control of Tundra Plant 

 Allocation Patterns 

 and Growth 



F. S. Chapin III, L. L. Tieszen, M. C. Lewis, 

 P. C. Miller, and B. H. McCown 



INTRODUCTION 



There is no significant difference in photosynthetic potential among 

 populations in the three major graminoid species in the coastal tundra at 

 Barrow (Chapter 4), and all populations receive the same low solar irra- 

 diance. Nevertheless, there is as much as a ten-fold difference in standing 

 crop among these same populations. Clearly, growth and primary pro- 

 duction are limited by more than plant photosynthetic potential or 

 energy available for photosynthesis. This chapter seeks to explain how 

 tundra plants control allocation patterns and growth to successfully ex- 

 ploit the cold-dominated, nutrient-limited environment of Barrow. 



Carbon and minerals may be allocated to: 1) leaf and stem growth, 

 which exerts a direct positive feedback on canopy photosynthesis by aug- 

 menting the quantity of photosynthetic tissues; 2) root production, 

 which increases the capacity of the plant to absorb water and nutrients; 

 3) rhizome production, which leads to vegetative reproduction and addi- 

 tional photosynthetic tissue and provides for carbon and nutrient stor- 

 age; and 4) inflorescences, which can lead to the dispersal and establish- 

 ment of genetically distinct individuals. The balance and timing of these 

 alternative allocation pathways determine the pattern of plant growth 

 and reproduction and the relative supply of carbon, water and nutrients 

 that the plant acquires. We place special emphasis on Dupontia fisheri, 

 which typifies the non-caespitose or single graminoid growth habit that 

 constitutes the major part of the coastal tundra vegetation at Barrow 

 (Chapter 3, Tieszen 1972b). 



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