Summary
A multispecies canopy photosynthesis simulation model was used to examine the importance of canopy structure in influencing light interception and carbon gain in mixed and pure stands of wheat (Triticum aestivum L.) and wild oat (Avena fatua L.), a common weedy competitor of wheat. In the mixtures, the fraction of the simulated canopy photosynthesis contributed by wheat was found to decline during the growing season and this decline was closely related to reductions in the amount of leaf area in upper canopy layers. For both species in mixture and in monoculture, simulated photosynthesis was greatest in the middle or upper-middle canopy layers and sensitivity analyses revealed that canopy photosynthesis was most sensitive to changes in leaf area and leaf inclination in these layers. Changes in LAI and leaf inclination affected canopy carbon gain differently for mixtures and monocultures, but the responses were not the same for the two species. Results from simulations where the structural characteristics of the two species were substituted indicated that species differences in leaf inclination, sheath area and the fraction of leaf area alive were of minor consequence compared with the differences in total leaf area in influencing relative canopy carbon gain in mixtures. Competition for light in these species mixtures appears to be influenced most by differences in the positioning of leaf area in upper canopy layers which determines, to a great extent, the amount of light intercepted.
Similar content being viewed by others
References
Araus JL, Tapia L (1987) Photosynthetic gas exchange characteristics of wheat flag leaf blades and sheaths during grain filling. Plant Physiol 85:667–673
Barnes PW, Jordan PW, Gold WG, Flint SD, Caldwell MM (1988) Competition, morphology and canopy structure in wheat (Triticum aestivum) and wild oat (Avena fatua) exposed to enhanced ultraviolet-B radiation. Functional Ecol 2:319–330
Benjamin LR (1984) Role of foliage habit in the competition between differently sized plants in carrot crops. Ann Bot (London) 53:549–557
Beyschlag W, Barnes PW, Flint SD, Caldwell MM (1988) Enhanced UV-B irradiation has no effect on photosynthetic characteristics of wheat (Triticum aestivum L.) and wild oat (Avena fatua L.) under greenhouse and field conditions. photosynthetica 22:516–525
Beyschlag W, Barnes PW, Ryel R, Caldwell MM, Flint SD (1990) Plant competition for light analyzed with a multispecies canopy model. II. Influence of photosynthetic characteristics on mixtures of wheat and wild oat. Oecologia 82:374–380
Black JN (1958) Competition between plants of different initial seed sizes in swards of subterranean clover (Trifolium subterraneum L.) with particular reference to leaf area and light microclimate. Aust J Agric Res 9:299–318
Black JN (1960) The significance of petiole length, leaf area, and light interception in competition between strains of subterranean clover (Trifolium subterraneum L.) grown in swards. Aust J Agric Res 11:277–291
Caldwell MM (1987) Plant architecture and resource competition. In: Schulze E-D, Zwölfer H (eds) Ecological studies, vol 61. Springer, Berlin Heidelberg New York, pp 164–179
Caldwell MM, Dean TJ, Nowak RS, Dzurec RS, Richards JH (1983a) Bunchgrass architecture, light interception, and wateruse efficiency: assessment by fiber optic point quadrats and gas exchange. Oecologia 59:178–184
Caldwell MM, Harris GW, Dzurec RS (1983b) A fiber optic point quadrat system for improved accuracy in vegetation sampling. Oecologia 59:417–418
Caldwell MM, Meister H-P, Tenhunen JD, Lange OL (1986) Canopy structure, light microclimate and leaf gas exchange of Quercus coccifera L. in a Portuguese macchia: measurements in different canopy layers and simulations with a canopy model. Trees 1:25–41
Duncan WG (1971) Leaf angles, leaf area, and canopy photosynthesis. Crop Sci 11:482–485
Eagles CF (1983) Relationship between competitive ability and yielding ability in mixtures and monocultures of populations of Dactylis glomerata L. Grass Forage Sci 38:21–24
Harper JL, Clatworthy JN (1963) The competitive biology of closely related species. VI. Analysis of the growth of Trifolium repens and T. fragiferum in pure and mixed populations. J Exp Bot 14:172–190
Jennings PR, Aquino RC (1968) Studies on competition in rice. III. The mechanism of competition among phenotypes. Evolution 22:529–542
Kropff MJ, Joenje W, Bastiaans L, Habekotte B, van Oene H, Werner R (1987) Competition between a sugar beet crop and populations of Chenopodium album L. and Stellaria media L. Neth J Agric Sci 35:525–528
Küppers M (1984) Carbon relations and competition between woody species in a Central European hedgerow. I. Photosynthetic characteristics. Oecologia 64:332–343
Küppers M (1985) Carbon relations and competition between woody species in a Central European hedgerow. IV. Growth form and partitioning. Oecologia 66:343–352
Legere A, Schreiber MM (1989) Competition and canopy architecture as affected by soybean (Glycine max) row width and density of redroot pigweed (Amaranthus retroflexus). Weed Sci 37:84–92
Martin MPLD, Field RJ (1987) Competition between vegetative plants of wild oat (Avena fatua L.) and wheat (Triticum aestivum L.). Weed Res 27:119–124
Monsi M, Uchijima Z, Oikawa T (1973) Structure of foliage canopies and photosynthesis. Ann Rev Ecol Syst 4:301–327
Neufeld HS, Meinzer FC, Wisdom CS, Sharifi MR, Rundel PW, Neufeld MS, Goldring Y, Cunningham GL (1988) Canopy architecture of Larrea tridentada (D.C.) Cov., a desert shrub: foliage orientation and direct beam interception. Oecologia 75:54–60
Pearcy RW, Tumosa N, Williams K (1981) Relationships between growth, photosynthesis and competitive interactions for a C3 and a C4 plant. Oecologia 48:371–376
Rhodes I, Stern WR (1978) Competition for light. In: Wilson JR (ed) Plant relations in pastures, CSIRO, East Melbourne, pp 175–189
Ross J (1970) Mathematical models of photosynthesis in a plant stand. In: Prediction and measurement of photosynthetic productivity, NV Noord-Nederlandse Drukkerij, Meppel, pp 29–45
Ross J (1975) Radiative transfer in plant communities. In: Monteith JL (ed) Vegetation and the atmosphere, Vol 1. Academic Press, New York, pp 13–55
Ryel R, Barnes PW, Beyschlag W, Caldwell MM, Flint SD (1990) Plant competition for light analyzed with a multispecies canopy model. I. Model development and influence of enhanced UV-B conditions on photosynthesis in mixed wheat and wild oat canopies. Oecologia 82:304–310
Saeki T (1963) Light relations in plant communities. In: Evans LT (ed) Environmental control of plant growth. Academic Press, New York, pp 79–94
Stoner WA, Miller PC, Miller PM (1978) A test of a model of irradiance within vegetation canopies at northern latitudes. Arctic Alpine Res 10:761–767
Warren Wilson J (1960) Inclined point quadrats. New Phytol 59:1–8
Warren Wilson J (1963) Estimation of foliage denseness and foliage angle by inclined point quadrats. Aust J Bot 11:95–105
Warren Wilson J (1967) Stand structure and light penetration. III. Sunlit foliage area. J Appl Ecol 4:159–165
Williams WA (1963) Competition for light between annual species of Trifolium during the vegetative phase. Ecology 44:475–485
Wilson GL, Ludlow MM (1983) The distribution of leaf photosynthetic activity in a mixed grass-legume pasture canopy. Photosyn Res 4:137–144
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Barnes, P.W., Beyschlag, W., Ryel, R. et al. Plant competition for light analyzed with a multispecies canopy model. Oecologia 82, 560–566 (1990). https://doi.org/10.1007/BF00319801
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00319801