Oilseed rape leaves falling off depends on both leaf nitrogen content and transmitted radiation
Compared to other crops, oilseed rape is known to absorb nitrate in large amount when available. However, absorbed nitrogen is not optimised by oilseed rape in terms of yield and seed quality; the latter remains weak in relation to nitrogen potentially remobilised towards the seeds, especially because of abscission of leaves with variable nitrogen content. Acquisition of knowledge on the processes involved in leaf falling off would then contribute to reduce nitrate leaching and to improve yield and seed quality.The general objective of our work was to evaluate the behaviour of different oilseed rape genotypes in response to nitrogen fertilisation, and to provide a grid for selection of genotypes with respect to a better remobilisation of absorbed nitrogen and a reduction of leaf abscission. In this aim, our experimental design consisted in analysing the different kinetics of green leaf area components of three genotypes, contrsted according to their size (dwarf and semi-dwarf) and architecture, grown in different conditions of nitrogen supply during two cycles.Experimental results concerning leaves falling off in different conditions (genotype, nitrogen availability, position on main stem), indicate a great variability in nitrogen content. Moreover large differences of transmitted radiation at the bottom of the canopy were observed. The objective of this paper is, concerning rapeseed bottom leaves, ⅰ) to test if the different couples of values of both bottom leaf nitrogen content and transmitted Photosynthetic Active Radiation (PARt) observed just before leaf falling off, are consistent with the hypothesis of leaf falling off linked to a single low net photosynthesis level, ⅱ) to analyse the genotypic variation on this process.
oilseed rape genotype x nitrogen interactions transmitted photosynthetically active radiation Leaf Area Index leaf falling off leaf nitrogen content
J.-M.Allirand A.Jullien A.Savin B.Ney
UMR INRA-INAPG Environnement et Grandes Cultures, 78850 Thiverval-Grignon, France
国际会议
第十二届国际油菜大会( The 12th International Rapeseed Congress)
武汉
英文
1134-1137
2007-03-26（万方平台首次上网日期，不代表论文的发表时间）