Sulfur uptake and remobilization are differentially affected by N deficiency in winter oilseed rape cultivars

ABSTRACT

Genotypic variation in nitrogen (N) efficiency of rapeseed is caused by differences in reproductive growth. This might be related to genotypic variation in sulfur (S) utilization. In this study it was tested if S deficiency in growing plant parts is induced under N-limiting conditions due to high sulfate accumulation in mature leaves which is poorly remobilized. Leaf S remobilization was compared under high and low N supply in four rapeseed cultivars that were grown in hydroponics with leaf-senescence induction by shading. Low N conditions did not increase sulfate accumulation in mature leaves. Total S remobilization from the leaves was higher under N-limiting than N-sufficient conditions. The proposed S deficiency in young plant parts therefore may not be more probable under low than under high N conditions. However, genotypic variation in S uptake and remobilization was found under N-limiting conditions only and might therefore contribute to genotypic variation in reproductive growth.

KEYWORDS:

• Nitrogen efficiency
• genotypic variation
• sulfur assimilation
• sulfate accumulation
• Brassica napus L

Acknowledgments

The authors thank Norddeutsche Pflanzenzucht Lembke (NPZ), Hohenlieth, for support of the project and Mrs Stephanie thor Straten and Bärbel Biegler for technical assistance.