Summary
Introduced African grasses are invading the grasslands of the Venezuelan savannas and displacing the native grasses. This work, which is part of a program to understand the reasons for the success of the African grasses, specifically investigates whether introduced and native grasses differ in some photosynthetic characteristics.
The responses to photon flux density, leaf temperature, leaf-air vapour pressure difference and leaf water potential of leaf photosynthetic rate of two introduced African C4 grasses (Hyparrhenia rufa and Melinis minutiflora) and of a lowland and a highland population of a native Venezuelan grass (Trachypogon plumosus) grown under controlled conditions were compared. These responses in all three species were typical of tropical C4 pasture grasses. The introduced grasses had higher maximum leaf conductance, net photosynthetic rates, and optimum temperature (H. rufa only) for photosynthesis than T. plumosus. However, T. plumosus was able to continue photosynthesis to lower leaf water potentials than the two introduced grasses, and the efficiency which it utilized water, light and mineral nutrients to fix carbon were similar to those of the introduced grasses.
The higher rates of leaf photosynthesis of the introduced grasses contributed to, but only partially explained, the higher growth rates compared to T. plumosus. The higher growth rates and nutrient concentration of the introduced grasses are consistent with their ability to establish rapidly, compete successfully for resources, and displace T. plumosus from moist, fertile sites. Conversely, the slower growth rate, lower nutrient concentrations, and superior water relations characteristics are consistent with the capacity of T. plumosus to resist invasion by introduced grasses in poorer sites.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Antonovics J, Lovett J, Bradshaw AD (1967) The evolution of adaptation to nutritional factors in populations of higher plants. In: Isotopes in plant nutrition and physiology. Proc Symp Vienna, pp 549–566
Baker NG (1978) Invasion and replacement in Californian and neotropical grasslands. In: Wilson JR (ed) Plant relations in pastures, CSIRO, Melbourne, pp 368–384
Baruch Z (1984a) Comparative ecophysiology of native and introduced grasses in a neotropical savanna. Proc 2nd Int Rangeland Congress, Adelaide, May 1984 (in press)
Baruch Z (1984b) Comparative responses of Trachypogon plumosus (Humb. and Bampl.) Nees. and Melinis minutiflora Beauv. to water stress. Oecologia (Berlin)
Baruch Z, Ludlow MM, Wilson JR Adaptation of tropical grasses to water stress. Oecologia (Berlin) (submittd)
Berry JA, Björkman O (1980) Photosynthetic response and adaptation to temperature in higher plants. Ann Rev P1 Physiol 31:491–543
Brown RH, Wilson JR (1983) Nitrogen response of Panicum species differing in CO2 fixation pathways. II. CO2 exchange characteristics. Crop Sci 23:1154–1159
Cabrera M, Baruch Z (1983) Growth responses to watering regimes in native and introduced pasture grasses from the derived savannas of the Coastal Cordillera (Venezuela). Report of Project S1-1135. CONICIT, Caracas
Christie EK (1975) Physiological response of semi-arid grasses. IV. Photosynthetic rates of Thyridolepis mitcheliana and Cenchrus ciliaris leaves. Aust J Agric Res 26:459–466
Christie EK, Moorby J (1975) Physiological response of semi-arid grasses. I. The influence of phosphorus supply on growth and phosphorus absorption. Aust J Agric Res 26:423–436
Davis R (1981) DATATRAN Mk III Datalogger. CSIRO Aust Div Trop Crops and Past, Trop Agron Tech Mem No 27
Davis R (1983) RD99B single board computer for instrumentation and control systems. CSIRO Aust Div Trop Crops and Past, Trop Agron Tech Mem No 34
Davis R, Ludlow MM (1981) A field gas exchange measuring system for pasture canopies. CSIRO Aust Div Trop Crops and Past, Trop Agron Tech Mem No 28
Ehleringer JR, Pearcy RW (1983) Variation in quantum yield of CO2 uptake among C3 and C4 plants. Plant Physiol 73:555–559
Fisher MJ (1982) Responses of Siratro (Macroptilium atropurpureum) to water stress. PhD thesis, University of Queensland, Brisbane
Gates CT (1970) A controlled environment facility for tropical pasture species. CSIRO Aust Div Trop Past, Tech Pap No 6
Gerloff GC (1963) Comparative mineral nutrition of plants. Ann Rev Pl Physiol 14:107–124
Hernandez A, Montilla G, Baruch Z (1983) Fenologia y reparticion de biomasa en gramineas nativas e introducidas en la Cordillera de la Costa. Report of Project S1-1135 CONICIT Caracas
Ludlow MM (1980a) Adaptive significance of stomatal responses to water stress. In: Turner NC, Kramer PJ (eds) Adaptation of plants to water and high temperature stress. Wiley, New York, pp 123–138
Ludlow MM (1980b) Stress physiology of tropical pasture plants. Trop Grassls 14:136–145
Ludlow MM (1981) Effect of temperature on light utilization efficiency of leaves of C3 legumes and C4 grasses. Photosynthesis Research 2:243–249
Ludlow MM (1982) Effect of external factors on photosynthesis and respiration of leaves. In: Dale JE, Milthorpe FL (eds) The growth and functioning of leaves. Cambridge Univ Press, pp 347–380
Ludlow MM, Ng TT (1976) Effect of water deficit on carbon dioxide exchange and leaf elongation rate of Panicum maximum var. trichoglume. Aust J Plant Physiol 3:401–413
Ludlow MM, Wilson GL (1971) Photosynthesis of tropical pasture plants. I. Illuminance, carbon dioxide concentration, leaf temperature and leaf-air vapor pressure difference. Aust J Biol Sci 24:449–470
Ludlow MM, Chu ACP, Clements RJ, Kerslake RG (1983) Adaptation of species of Centrosema to water stress. Aust J Plant Physiol 10:119–130
Ludlow MM, Fisher MJ, Wilson JR (1985) Stomatal adjustment to water deficits in three tropical grasses and a tropical legume grown in controlled conditions and in the field. Aust J Plant Physiol 12:131–149
McIvor JG (1984) Phosphorus requirements and responses of tropical pasture species: native and introduced grasses and introduced legumes. Aust J Exp Agric An Husb 24:370–378
Medina E, Mendoza A, Montes R (1977) Balance nutricionaly produccion de materia organica en las sabanas de Trachypogon de Calabozo, Venezuela. Bol Soc Ven Cienc Nat 134:101–120
Mooney HA, Ferrar PJ, Slayter RO (1978) Photosynthetic capacity and carbon allocation patterns in diverse growth forms of Eucalyptus. Oecologia (Berlin) 36:103–111
Nassery H (1970) Phosphate absorption by plants from habitats of different phosphate status. II. Absorption and incorporation of phosphate by intact plants. New Phytol 69:197–203
Parsons JJ (1972) Spread of African pasture grasses to the American tropics. J Range Manage 25:12–17
San Jose J, Garcia MJ (1981) Factores ecologicos operacionales en la production de materia organica de los sabanos de Trachypogon. Bol Soc Ven Cienc Nat 139:347–374
Vareschi V (1969) Las sabanas del Valle de Caracas. In: Ecologia Vegetal-Fauna. Estudio de Caracas I. Biblioteca UCV, Caracas
Williams CH, Twine JR (1967) Determination of nitrogen, sulphur, potassium, sodium, calcium and magnesium in plant material by automatic analysis. CSIRO Aust Div Plant Indust Technical Paper No. 24
Wilson JR, Brown RH (1983) Nitrogen response of Panicum species differing in CO2 fixation pathways. II. Growth analysis and carbohydrate accumulation. Crop Sci 23:1148–1153
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Baruch, Z., Ludlow, M.M. & Davis, R. Photosynthetic responses of native and introduced C4 grasses from Venezuelan savannas. Oecologia 67, 388–393 (1985). https://doi.org/10.1007/BF00384945
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00384945