Abstract
The rate of photosynthesis and its relation to tissue nitrogen content was studied in leaves and siliques of winter oilseed rape (Brassica napus L.) growing under field conditions including three rates of nitrogen application (0, 100 or 200 kg N ha-1) and two levels of irrigation (rainfed or irrigated at a deficit of 20 mm).
The predominant effect of increasing N application under conditions without water deficiency was enhanced expansion of photosynthetically active leaf and silique surfaces, while the rate of photosynthesis per unit leaf or silique surface area was similar in the different N treatments. Thus, oilseed rape did not increase N investment in leaf area expansion before a decline in photosynthetic rate per unit leaf area due to N deficiency could be avoided. Much less photosynthetically active radiation penetrated into high-N canopies than into low-N canopies. The specific leaf area increased markedly in low light conditions, causing leaves in shade to be less dense than leaves exposed to ample light.
In both leaves and siliques the photosynthetic rate per unit surface area responded linearly to increasing N content up to about 2 g m-2, thus showing a constant rate of net CO2 assimilation per unit increment in N (constant photosynthetic N use efficiency). At higher tissue N contents, photosynthetic rate responded less to changes in N status. Expressed per unit N, light saturated photosynthetic rate was three times higher in leaves than in silique valves, indicating a more efficient photosynthetic N utilization in leaves than in siliques. Nevertheless, from about two weeks after completion of flowering and onwards total net CO2 fixation in silique valves exceeded that in leaves because siliques received much higher radiation intensities than leaves and because the leaf area declined rapidly during the reproductive phase of growth.
Water deficiency in late vegetative and early reproductive growth stages reduced the photosynthetic rate in leaves and, in particular, siliques of medium- and high-N plants, but not of low-N plants.
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Abbreviations
- CAI:
-
crop area index
- LAI:
-
leaf area index
- PAR:
-
photosynthetically active radiation
- PPFD:
-
photosynthetic photon flux density
- SLA:
-
specific leaf area
References
Allen E J and Morgan D G 1972 A quantitative analysis of the effect of N on growth, development and yield of oilseed rape. J. Agric. Sci. Camb. 78, 315–324.
Barraclough P B 1989 Root growth, macro-nutrient uptake dynamics and soil fertility requirements of a high-yielding oilseed rape crop. Plant and Soil 119, 59–70.
Chapin F SIII, Bloom A J, Field C B and Waring R H 1987 Plant response to multiple environmental factors. BioScience 37, 49–57.
Evans J R 1983 Nitrogen and photosynthesis in the flag leaf of wheat (Triticum aestivum L.). Plant Physiol 72, 297–302.
Evans J R 1989 Photosynthesis and nitrogen relationship in leaves of C3 plants. Oecologia 78, 9–19.
Field C and Mooney H A 1986 The photosynthesis-nitrogen relationship in wild plants.In On the Economy of Form and Function. Ed. T JGivinsh. pp 25–55. Cambridge University Press, Cambridge, UK.
Freyman S, Chanetski W A and Crookston R K 1973 Role of leaves in the formation of seeds in rape. Can. J. Plant Sci. 53, 693–694.
Hay R K M and Walker A J 1989 An Introduction to the Physiology of Crop Yield, Part one. Longman, Harlow, UK.
Holmes M R J 1980 Nutrition of Oilseed Rape Crop. Applied Science Publishers Ltd., London, UK. 158 p.
Inanaga S, Kumura A and Murata Y 1979 Photosynthesis and yield of rapeseed. Proc. Crop Sci. Soc. Jpn. 13, 169–173.
Krogman K and Hobbs E H 1975 Yield and morphological response of rape (Brassica campestris cv. Span) to soil fertility and irrigation. Can. J. Plant Sci. 55, 903–909.
Lambers H 1987 Does variation in photosynthetic rate explain variation in growth rate and yield? Neth. J. Agric. Sci. 35, 505–519.
Major D J 1975 Stomatal frequency and distribution in rape. Can. J. Plant Sci. 55, 1077–1078
Porter P M 1993 Canola response to boron and nitrogen grown on the south-eastern coastal plain. J. Plant Nutr. 16, 2371–2381.
Sage R F and Pearcy R W 1987 The nitrogen use efficiency of C3 and C4 plants. Ill. Leaf nitrogen effects on the activity of carboxylating enzymes inChenopodium album L. andAmaranthus retroflexus L. Plant Physiol. 85, 355–359.
Sage R F, Sharkey T D and Pearcy R W 1990 The effect of leaf nitrogen and temperature on the CO2 response of photosynthesis in the C3 dicotChenopodium album L. Aust. J. Plant Physiol 17, 135–148.
SAS Institute 1990 SAS Users guide: Statistics, 6th ed. SAS Institute, Inc, Cary, NC, USA.
Schjoerring J K, Bock J G H, Gammelvind L, Jensen C R and Mogensen V O 1995 Nitrogen incorporation and remobilization in different shoot components of field- grown winter oilseed rape (Brassica napus L.) as affected by rate of nitrogen application and irrigation. Plant and Soil 177, 255–264.
Sinclair T R and Horie T 1989 Leaf nitrogen, photosynthesis and crop radiation use efficiency: a review. Crop Sci. 29, 90–98.
Stitt M and Schulze D 1994 Does Rubisco control the rate of photosynthesis and plant growth? An exercise in molecular ecophysiology. Plant Cell Environ. 17, 465–487.
VanKeulen H, Goudriaan J and Seligman N G 1989 Modelling the Effects of nitrogen on canopy development and crop growth.In Plant canopies: Their Growth, Form and Function. Eds. GRussell, BMarshall and P GJarvis. pp 83–104. Cambridge University Press, Cambridge, UK.
Wong S, Cowan I R and Farquhar G D 1985 Leaf conductance in relation to rate of CO2 assimilation. I. Influence of nitrogen nutrition, phosphorus nutrition, photon flux density, and ambient partial pressure of CO2 during ontogeny. Plant Physiol. 69, 591–596.
Wright G C, Smith C J and Woodroofe M R 1988 The effect of irrigation and nitrogen fertilizer on rapeseed (Brassica napus) production in South-eastern Australia. I. Growth and seed yield. Irrig. Sci. 9, 1–13.
Yusuf R I and Bullock D G 1993 Effect of several production factors on two varieties of rapeseed in the central United States. J. Agron. Crop Sci. 171, 46–48.
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Gammelvind, L.H., Schjoerring, J.K., Mogensen, V.O. et al. Photosynthesis in leaves and siliques of winter oilseed rape (Brassica napus L.). Plant Soil 186, 227–236 (1996). https://doi.org/10.1007/BF02415518
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DOI: https://doi.org/10.1007/BF02415518