Skip to main content
Log in

Irradiance and temperature effects on photosynthesis of tussock tundra Sphagnum mosses from the foothills of the Philip Smith Mountains, Alaska

  • Original Papers
  • Published:
Oecologia Aims and scope Submit manuscript

Summary

Photosynthetic characteristics of three species of Sphagnum common in the foothills of the Brooks Range on the North Slope of Alaska were investigated. Generally, light-saturated rates of net photosynthesis decreased in the order S. squarrosum, S. angustifolium, and S. warnstorfii when plants were grown under common growth chamber conditions. For field-grown S. angustifolium, average light compensation point at 10°C was 37 μmol m-2s-1 photosynthetic photon flux density (PPFD), and light saturation occurred between 250 and 500 μmol m-2 s-1. At 20°C, compensation point increased to 127 μmol m-2s-1 and the PPFD required for light saturation increased to approximately 500 μmol m-2s-1, while maximum rates of CO2 uptake increased only slightly. Light response curves of chamber-grown plants exhibited substantially lower compensation points and higher light-saturated rates of CO2 assimilation than field-grown material, due perhaps to a higher percentage of green, photosynthetically competent tissue. All three species exhibited broad responses to temperature, with optima near 20°C, and maintained at least 75% of maximum assimilation between approx. 13° and 30°C. Rates at 5°C were approx. 50% of maximum. Studies of the microclimate of Sphagnum at the field research site suggest that CO2 uptake should occur at near light-saturated rates during the day in open tussock tundra but that PPFD may often be limiting under Salix and Betula canopies in a water track drainage. Simulations using a simple model provided a seasonal estimate of 0.78 g dry weight (DW) of S. angustifolium produced from each initial g of photosynthetic tissue under willow canopies, assuming no water limitations. Although the simulation model suggests that production would be 66% higher in open tussock tundra, S. angustifolium is rarely found in this potentially more stressful habitat. To explain the relative abundance of Sphagnum in shaded water track areas as compared to open tussock tundra, we postulate that the vascular plant canopies provide protection from adverse effects of high temperatures, excess irradiance and reduced water availability. Under conditions of normal water availability, removal of the vascular plant cover did not affect the tissue water content of S. squarrosum, but resulted in a strong decrease in photosynthetic capacity, accompanied by chlorophyll bleaching. These results suggest that photoinhibition may limit production under certain conditions.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

References

  • Alexander V, Billington MM (1986) Nitrogen fixation in the Alaskan taiga. In: Van Cleve K, Chapin FS III, Flanagan PW, Viereck LA, Dyrness CT (eds), Forest ecosystems in the Alaskan taiga: a synthesis of structure and function. Springer, Berlin Heidelberg New York, pp 112–120

    Google Scholar 

  • Busby JR, Bliss LC, Hamilton CD (1978) Microclimate control of growth rates and habitats of the boreal forest mosses, Tomenthypnum nitens and Hylocomium splendens. Ecol Mono 48:95–110

    Google Scholar 

  • Chapin FS, Shaver GR (1985) Arctic. In: Chabot BF, Mooney HA (eds) Physiological ecology of North American plant communities. Chapman and Hall, New York London, pp 16–40

    Google Scholar 

  • Clymo RS, Hayward PM (1982) The ecology of Sphagnum. In: Smith AJF (ed), Bryophyte ecology, Chapman and Hall, London-New York, pp 229–289

    Google Scholar 

  • Crum HA, Anderson LE (1981) Mosses of Eastern North America. Columbia Univ Press, New York

    Google Scholar 

  • Demmig B, Winter K, Krüger A, Czygan FC (1987) Photoinhibition and zeaxanthin formation in intact leaves. Plant Physiol 84:218–224

    Google Scholar 

  • Hicklenton PR, Oechel WC (1976) Physiological aspects of the ecology of Dicranum fuscescens in the subarctic. I. Acclimation and acclimation potential of CO2 exchange in relation to habitat, light and temperature. Can J Bot 54:1104–1119

    Google Scholar 

  • Lange OL, Kilian E, Meyer A, Tenhunen JD (1984) Measurements of lichen photosynthesis in the field with a portable steady-state CO2 porometer. Lichenologist 16:1–9

    Google Scholar 

  • Miller PC, Oechel WC, Stoner WA, Sveinbjörnsson B (1978) Simulation of CO2 uptake and water relations of four arctic bryophytes at Point Barrow, Alaska. Photosynthetica 12:7–20

    Google Scholar 

  • Murray KJ, Harley PC, Beyers J, Walz H, Tenhunen JD (1989a) Water content effects on photosynthetic response of Sphagnum mosses from the foothills of the Philip Smith Mountains, Alaska. Oecologia (in press)

  • Murray KJ, Tenhunen JD, Kummerow J (1989b) Limitations on Sphagnum growth and net primary production in the foothills of the Philip Smith Mountains, Alaska. Oecologia 79:244–250

    Google Scholar 

  • Ng E, Miller PC (1977) Validation of a model of the effect of tundra vegetation on soil temperatures. Arct Alp Res 9:89–104

    Google Scholar 

  • Oechel WC (1976) Seasonal patterns of temperature response of CO2 flux and acclimation in arctic mosses growing in situ. Photosynthetica 10:447–456

    Google Scholar 

  • Oechel WC, Collins NJ (1976) Comparative CO2 exchange patterns in mosses from two tundra habitats at Barrow, Alaska. Can J Bot 54:1355–1369

    Google Scholar 

  • Oechel WC, Sveinbjörnsson B (1978) Primary production processes in arctic bryophytes at Barrow, Alaska. In: Tieszen LL (ed) Vegetation and production ecology of an Alaskan arctic tundra. Springer, Berlin Heidelberg New York, pp 269–298

    Google Scholar 

  • Oechel WC, Van Cleve K (1986) The role of bryophytes in nutrient cycling in the taiga. In: Van Cleve K, Chapin FS III, Flanagan PW, Viereck LA, Dyrness CT (eds) Forest ecosystems in the Alaskan taiga: a synthesis of structure and function. Springer, Berlin Heidelberg New York, pp 121–137

    Google Scholar 

  • Powles SB (1984) Photoinhibition of photosynthesis induced by visible light. Ann Rev Plant Physiol 35:15–44

    Google Scholar 

  • Rastorfer JR (1970) Effect of light intensity and temperature on photosynthesis and respiration of two East Antarctic mosses, Bryum argenteum and Bryum antarcticum. Bryologist 73:544–556

    Google Scholar 

  • Skre O, Oechel WC (1981) Moss functioning in different taiga ecosystems in interior Alaska. I. Seasonal, phenotypic, and drought effects on photosynthesis and response patterns. Oecologia 48:50–59

    Google Scholar 

  • Smith E (1937) The influence of light and carbon dioxide on photosynthesis. Gen Physiol 20:807–830

    Article  Google Scholar 

  • Stålfelt MG (1937) Der Gasaustausch der Moose. Planta 27:30–60

    Google Scholar 

  • Thomson J (1982) Lichen vegetation and ecological patterns in the high arctic. J Hattori Bot Lab 53:361–364

    Google Scholar 

  • Titus JE, Wagner DJ (1984) Carbon balance for two Sphagnum mosses: water balance resolves a physiological paradox. Ecology 65:1765–1774

    Google Scholar 

  • Walker DA, Binnian E, Evans BM, Lederer ND, Nordstrand E, Webber PJ (1989) Terrain, vegetation, and landscape evolution of the R4D research site, Brooks Range Foothills, Alaska. Holarctic Ecology (in press)

Download references

Author information

Authors and Affiliations

Authors

Rights and permissions

Reprints and permissions

About this article

Cite this article

Harley, P.C., Tenhunen, J.D., Murray, K.J. et al. Irradiance and temperature effects on photosynthesis of tussock tundra Sphagnum mosses from the foothills of the Philip Smith Mountains, Alaska. Oecologia 79, 251–259 (1989). https://doi.org/10.1007/BF00388485

Download citation

  • Received:

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF00388485

Key words

Navigation