caa a22 4500 477111009 CHVBK 20180405111609.0 cr unu---uuuuu 170330e19961001xx s 000 0 eng 10.1007/BF02415518 doi (NATIONALLICENCE)springer-10.1007/BF02415518 Photosynthesis in leaves and siliques of winter oilseed rape ( Brassica napus L.) [Elektronische Daten] [L. Gammelvind, J. Schjoerring, V. Mogensen, C. Jensen, J. Bock] 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. Kluwer Academic Publishers, 1996 Brassica napus nationallicence canola nationallicence oilseed rape nationallicence nitrogen nutrition nationallicence irrigation nationallicence photosynthesis nationallicence photosynthetic nitrogen use efficiency nationallicence CAI : crop area index nationallicence LAI : leaf area index nationallicence PAR : photosynthetically active radiation nationallicence PPFD : photosynthetic photon flux density nationallicence SLA : specific leaf area nationallicence Gammelvind L. Plant Nutrition Laboratory Department of Agricultural Sciences, The Royal Veterinary and Agricultural University, Thorvaldsensvej 40, DK-1871, Frederiksberg C, Copenhagen, Denmark aut Schjoerring J. Plant Nutrition Laboratory Department of Agricultural Sciences, The Royal Veterinary and Agricultural University, Thorvaldsensvej 40, DK-1871, Frederiksberg C, Copenhagen, Denmark aut Mogensen V. Agrometeorology and Bioclimatology, Department of Agricultural Sciences, The Royal Veterinary and Agricultural University, Thorvaldsensvej 40, DK-1871, Frederiksberg C, Copenhagen, Denmark aut Jensen C. Agrometeorology and Bioclimatology, Department of Agricultural Sciences, The Royal Veterinary and Agricultural University, Thorvaldsensvej 40, DK-1871, Frederiksberg C, Copenhagen, Denmark aut Bock J. Plant Nutrition Laboratory Department of Agricultural Sciences, The Royal Veterinary and Agricultural University, Thorvaldsensvej 40, DK-1871, Frederiksberg C, Copenhagen, Denmark aut Plant and Soil Kluwer Academic Publishers 186/2(1996-10-01), 227-236 0032-079X 186:2<227 1996 186 11104 https://doi.org/10.1007/BF02415518 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF02415518 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Gammelvind L. Plant Nutrition Laboratory Department of Agricultural Sciences, The Royal Veterinary and Agricultural University, Thorvaldsensvej 40, DK-1871, Frederiksberg C, Copenhagen, Denmark aut NATIONALLICENCE 700 1- Schjoerring J. Plant Nutrition Laboratory Department of Agricultural Sciences, The Royal Veterinary and Agricultural University, Thorvaldsensvej 40, DK-1871, Frederiksberg C, Copenhagen, Denmark aut NATIONALLICENCE 700 1- Mogensen V. Agrometeorology and Bioclimatology, Department of Agricultural Sciences, The Royal Veterinary and Agricultural University, Thorvaldsensvej 40, DK-1871, Frederiksberg C, Copenhagen, Denmark aut NATIONALLICENCE 700 1- Jensen C. Agrometeorology and Bioclimatology, Department of Agricultural Sciences, The Royal Veterinary and Agricultural University, Thorvaldsensvej 40, DK-1871, Frederiksberg C, Copenhagen, Denmark aut NATIONALLICENCE 700 1- Bock J. Plant Nutrition Laboratory Department of Agricultural Sciences, The Royal Veterinary and Agricultural University, Thorvaldsensvej 40, DK-1871, Frederiksberg C, Copenhagen, Denmark aut NATIONALLICENCE 773 0- Plant and Soil Kluwer Academic Publishers 186/2(1996-10-01), 227-236 0032-079X 186:2<227 1996 186 11104 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer