Abstract
Maximal rates of CO2 assimilation of 8–11 μmol m-2 s-1 at ambient CO2 concentration were measured for Dendrosenecio keniodendron, D. brassica, Lobelia telekii and L. keniensis during the day in the natural habitat of these plants at 4,200 m elevation on Mt. Kenya. Even at these maximal rates, the CO2 uptake of all species was found to correspond to the linear portion of the CO2 response curve, with a calculated stomatal limitation for CO2 diffusion of 42%. Photosynthesis was strongly reduced at temperatures above 15° C. In contrast to this sensitivity to high temperatures, frozen leaves regained full photosynthetic capacity immediately after thawing. Stomata responded to dry air, but not to low leaf water potentials which occurred in cold leaves and at high transpiration rates. During the day reduced rates of CO2 uptake were associated with reduced light interception due to the erect posture of the rosette leaves and with high temperatures. Stomata closed at vapour pressure deficits which were comparable in magnitude to those characteristic of many lowland habitats (40 mPa Pa-1).
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References
Beck E, Scheibe R, Senser M, Müller W (1980) Estimation of leaf and stem growth of unbranched Senecio keniodendron trees. Flora 170:68–76
Beck E, Senser M, Scheibe R, Steiger H-M, Pongratz P (1982) Frost avoidance and freezing tolerance in afroalpine “giant rosette” plants. Plant, Cell and Environment 5:215–222
Beck E, Schlüter I, Scheibe R, Schulze E-D (1984A) Growth rates and population rejuvenation of East African giant ground (Dendrosenecio keniodendron). Flora 175:243–248
Beck E, Schulze E-D, Senser M, Scheibe R (1984B) Equilibrium freezing of leaf water and extracellular ice formation in afroalpine giant rosette plants. Planta (in press)
Farquhar GD, Sharkey TD (1982) Stomatal conductance and photosynthesis. Ann Rev Plant Phys 33:317–345
Goldstein G, Meinzer F (1983) Influence of insulating dead leaves and low temperatures on water balance in an Andean giant rosette plant. Plant, Cell and Environment 6:649–656
Hedberg O (1974) Features of afroalpine plant ecology. Acta Phytogeogr Suec 49:1–144
Körner Ch, Scheel JA, Bauer H (1979) Maximum leaf diffusion conductance in vascular plants. Photosynthetica 13:45–82
Larcher W, Bauer H (1981) Ecological significance of resistance to low temperature. In: Lange OL, Nobel PS, Osmond CB, Ziegler H (eds) Encyclopedia of Plant Physiology, vol 12A. Springer, Berlin Heidelberg New York, pp 403–438
Mooney HA, Ehleringer JR, Björkman O (1977) The energy balance of leaves of the evergreen desert shrub Atriplex hymenelytra. Oecologia 29:301–310
Pisek A, Larcher W, Moser W, Rack I (1969) Temperaturebereich der Photosynthese und Grenztemperaturen des Lebens der Blätter verschiedener Spermatophyten. III. Temperaturabhängigkeit und optimaler Temperaturbereich der Netto-Photosynthese. Flora (Jena) Abt B 158:608–630
Schulze E-D (1982) Plant life forms and their carbon, water and nutrient relations. In: Lange OL, Nobel PS, Osmond CB, Ziegler H (eds) Encyclopedia of Plant Physiology, vol 12B. Springer, Berlin Heidelberg New York, pp 616–676
Schulze E-D, Hall AE (1982) Stomatal Responses, water loss, and CO2 assimilation rates of plants in contrasting envorinments. In: Lange OL, Nobel PS, Osmond CB, Ziegler H (eds) Encyclopedia of Plant Physiology, vol 12B. Springer, Berlin Heidelberg New York, pp 181–230
Schulze E-D, Hall AE, Lange OL, Walz H (1982) A portable steady-state porometer for measuring the carbon dioxide and water vapour exchange of leaves under natural conditions. Oecologia 53:141–145
Shackel K (1984) Theoretical and experimental errors for in situ measurements of plant water potential. Plant Physiol (in press)
Smith AP, Young TP (1982) The cost of reproduction in Senceio keniodendron a giant rosette species of Mt Kenya. Oecologia 55:243–247
Tranquillini W (1957) Strandortsklima, Wasserbilanz und CO2-Gaswechsel junger Zirben (Pinus cambra L) an der alpinen Waldgrenze. Planta 49:612–661
Tranquillini W (1982) Frost-drought and its ecological significance. In: Lange OL, Nobel PS, Osmond CB, Ziegler H (eds) Encyclopedia of Plant Physiology, vol 12B. Springer, Berlin Heidelberg New York, pp 379–400
Werk KS, Ehleringer J (1984) Non-random leaf orientation in Lactuca serriola L. Plant Cell Environ 7:81–87
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Schulze, E.D., Beck, E., Scheibe, R. et al. Carbon dioxide assimilation and stomatal response of afroalpine giant rosette plants. Oecologia 65, 207–213 (1985). https://doi.org/10.1007/BF00379219
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DOI: https://doi.org/10.1007/BF00379219