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Seasonal and inter-annual photosynthetic response of representative C4 species to soil water content and leaf nitrogen concentration across a tropical seasonal floodplain

  • K. B. Mantlana (a1) (a2) (a3), A. Arneth (a4) (a5), E. M. Veenendaal (a2) (a6), P. Wohland (a4) (a7), P. Wolski (a6), O. Kolle (a1) and J. Lloyd (a7)...

We examined the seasonal and inter-annual variation of leaf-level photosynthetic characteristics of three C4 perennial species, Cyperus articulatus, Panicum repens and Imperata cylindrica, and their response to environmental variables, to determine comparative physiological responses of plants representing particular microhabitats within a seasonal tropical floodplain in the Okavango River Delta, Botswana. Five measurement campaigns were carried out over a period of 2 y which covered two early rainy seasons, two late rainy seasons and one dry season. For all three species, light-saturated net photosynthetic rates (Asat) and stomatal conductance (gsat) decreased with decreasing soil water content with a seasonal range for Asat of approximately 5–45 μmol m−2 s−1, and for gsat of 0.03–0.35 mol m−2 s−1. The species representing the wettest microhabitat (Cyperus) had the highest gsat at low leaf-to-air vapour pressure deficits (Dl), the highest ratio of intercellular to ambient CO2 concentration (Ci/Ca), as well as the highest degree of variation in Ci/Ca from season to season. We interpret this as being indicative of its adaptation to a moist growth environment allowing for non-conservative water use strategies as soil moisture is usually abundant. For all three species there was significant variation in photosynthetic fluxes from one year to another that was related to variation in leaf nitrogen and phosphorus. This study shows that when assessing the role of savanna stands in large-scale carbon balance models, the remarkable inter-annual variation in leaf photosynthesis reported in this study should be taken into account.

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1Corresponding author, at Global Change Research Group address; Email:
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G. ALMENDROS , D. KGATHI , M. SEKHWELA , M. ZANCADA , P. TINOCO & M. PARDO 2003. Biogeochemical assessment of resilient humus formations from virgin and cultivated northern Botswana soils. Journal of Agricultural and Food Chemistry 51:43214330.

N. P. R. ANTEN , M. J. A. WERGER & E. MEDINA 1998. Nitrogen distribution and leaf area indices in relation to photosynthetic nitrogen use efficiency in savanna grasses. Plant Ecology 138:6375.

S. ARCHER , C. D. COUGHENOUR , G. W. FERNANDEZ , J. HAY , W. HOFFMAN , C. KLINK , J. F. SILVA & O. T. SOLBRIG 1996. Savanna biodiversity and ecosystem properties. Pp. 207224 in O. T. Solbrig , E. Medina & J. F. Silva (eds.). Biodiversity and savanna ecosystem processes: a global perspective. Springer Verlag, Berlin.

Z. BARUCH 1996. Ecophysiological aspects of the invasion by African grasses and their impact on biodiversity and function of neotropical savannas. Pp. 7993 in O. T. Solbrig , E. Medina & J. F. Silva (eds.). Biodiversity and savanna ecosystem processes: a global perspective. Springer Verlag, Berlin.

Z. BARUCH & B. BILBAO 1999. Effects of fire and defoliation on the life history of native and invader C4 grasses in a Neotropical savanna. Oecologia 119:510520.

Z. BARUCH , M. M. LUDLOW & R. DAVIS 1985. Photosynthetic responses of native and introduced C4 grasses from Venezuelan savannas. Oecologia 67:338393.

C. V. BEALE , J. I. L. MORISON & S. P. LONG 1999. Water use efficiency of C4 perennial grasses in a temperate climate. Agricultural and Forest Meteorology 96:103115.

M. C. BONYONGO , G. J. BREDENKAMP & E. VEENENDAAL 2000. Floodplain vegetation in the Nxaraga Lagoon area, Okavango Delta, Botswana. South African Journal of Botany 66:1521.

C. T. BRYSON & R. CARTER 2004. Biology of pathways for invasive weeds. Weed Technology 18:12161220.

J. A. BUNCE 1998. Effects of environment during growth on the sensitivity of leaf conductance to changes in humidity. Global Change Biology 4:269274.

J. COMSTOCK & J. EHLERINGER 1993. Stomatal response to humidity in common bean (Phaseolus vulgaris): implications for maximum transpiration rate, water-use efficiency and productivity. Australian Journal of Plant Physiology 20:669691.

E. H. DE LUCIA , D. WHITEHEAD & M. J. CLEARWATER 2003. The relative limitation of photosynthesis by mesophyll conductance in co-occurring species in a temperate rainforest dominated by the conifer Dacrydium cupressinum. Functional Plant Biology 30:11971204.

J. R. EHLERINGER , T. E. CERLING & B. R. HELLIKER 1997. C4 photosynthesis, atmospheric CO2 and climate. Oecologia 112:285299.

W. N. ELLERY & T. S. MCCARTHY 1994. Principles for the sustainable utilization of the Okavango Delta ecosystem, Botswana. Biological Conservation 70:159168.

M. HEINL , P. FROST , C. VANDERPOST & J. SLIVA 2007. Fire activity on drylands and floodplains in the southern Okavango Delta, Botswana. Journal of Arid Environments 68:7787.

K. HIKOSAKA 2004. Interspecific difference in the photosynthesis-nitrogen relationship: patterns, physiological causes, and ecological importance. Journal of Plant Research 117:481494.

Y. JIA & V. M. GRAY 2004. Influence of phosphorus and nitrogen on photosynthetic parameters and growth in Vicia faba L. Photosynthetica 42:535542.

M. B. JONES 1988. Photosynthetic responses of C3 and C4 wetland species in a tropical swamp. Journal of Ecology 76:253262.

B. S. KGOPE 2004. Differential photosynthetic responses of broad- and fine-leaved savanna trees to elevated temperatures. South African Journal of Botany 70:760766.

A. K. KNAPP 1993. Gas exchange dynamics in C3 and C4 grasses: consequences of differences in stomatal conductance. Ecology 74:113123.

J. LLOYD & G. D. FARQUHAR 1994. C-13 discrimination during CO2 assimilation by the terrestrial biosphere. Oecologia 99:201215.

G. E. MACDONALD 2004. Cogongrass (Imperata cylindrica) – biology, ecology, and management. Critical Reviews in Plant Science 23:367380.

H. MAHERALI , H. B. JOHNSON & R. B. JACKSON 2003. Stomatal sensitivity to vapour pressure difference over a subambient to elevated CO2 gradient in a C3/C4 grassland. Plant Cell and Environment 26:12971306.

T. S. MCCARTHY & W. N. ELLERY 1994. The effect of vegetation on soil and ground water chemistry and hydrology of islands in the seasonal swamps of the Okavango Fan, Botswana. Journal of Hydrology 154:169193.

G. F. MIDGLEY , S. J. E. WAND & N. W. PAMMENTER 1999. Nutrient and genotypic effects on CO2-responsiveness: photosynthetic regulation in Leucadendron species of a nutrient-poor environment. Journal of Experimental Botany 50:533542.

A. C. MIRANDA , H. S. MIRANDA , J. LLOYD , J. GRACE , R. J. FRANCEY , J. A. MCINTYRE , P. MEIR , P. RIGGAN , R. LOCKWOOD & J. BRASS 1997. Fluxes of carbon, water and energy over Brazilian cerrado: an analysis using eddy covariance and stable isotopes. Plant Cell and Environment 20:315328.

J. I. L. MORISON & R. M. GIFFORD 1983. Stomatal sensitivity to carbon dioxide and humidity. Plant Physiology 71:789796.

E. OLIVARES , D. VIZCAINO & A. GAMBOA 2002. Mineral nutrition of three aquatic emergent macrophytes in a managed wetland in Venezuela. Journal of Plant Nutrition 25:475496.

R. OREN , J. S. SPERRY , G. G. KATUL , D. E. PATAKI , B. E. EWERS , N. PHILLIPS & K. V. R. SCHAEFER 1999. Survey and synthesis of intra- and interspecific variation in stomatal sensitivity to vapour pressure deficit. Plant, Cell and Environment 22:15151526.

M. T. F. PIEDADE , W. J. JUNK & S. P. LONG 1991. The productivity of the C4 grass Echinochloa polystachya on the Amazon floodplain. Ecology 72:14561463.

P. B. REICH , D. S. ELLSWORTH & M. B. WALTERS 1998. Leaf structure (specific leaf area) modulates photosynthesis-nitrogen relations: evidence from within and across species and functional groups. Functional Ecology 12:948958.

P. B. REICH , C. BUSCHENA , M. G. TJOELKER , K. WRAGE , J. KNOPS , D. TILMAN & J. L. MACHADO 2003. Variation in growth rate and ecophysiology among 34 grassland and savanna species under contrasting N supply: a test of functional group differences. New Phytologist 157:617631.

R. F. SAGE & R. W. PEARCY 1987. The nitrogen use efficiency of C3 and C4 plants. II. Leaf nitrogen effects on the gas exchange characteristics of Chenopodium album L. and Amaranthus retroflexus L. Plant Physiology 84:959963.

R. F. SAGE , R. W. PEARCY & J. R. SEEMANN 1987. The nitrogen use efficiency of C3 and C4 Plants. III. Leaf nitrogen effects on the activity of carboxylating enzymes in Chenopodium album (L) and Amaranthus retroflexus (L). Plant Physiology 85:355359.

G. SIMIONI , X. LE ROUX , J. GIGNOUX & A. S. WALCROFT 2004. Leaf gas exchange characteristics and water- and nitrogen-use efficiencies of dominant grass and tree species in a West African savanna. Plant Ecology 173:233246.

D. R. TAUB & M. T. LERDAU 2000. Relationship between leaf nitrogen and photosynthetic rate for three NAD-ME and three NADP-ME C4 grasses. American Journal of Botany 87:412417.

K. THOMPSON 1985. Emergent plants of permanent and seasonally-flooded wetlands. Pp. 43107 in P. W. Denny (ed.). The ecology and management of African wetland vegetation. Junk Publishers, Dordrecht. 344 pp.

S. TOOTH & T. S. MCCARTHY 2007. Wetlands in drylands: geomorphological and sedimentological characteristics, with emphasis on examples from southern Africa. Progress in Physical Geography 31:341.

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Journal of Tropical Ecology
  • ISSN: 0266-4674
  • EISSN: 1469-7831
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