Influence of Sulphur and Nitrogen Supply on the Pigment Content of Oilseed Rape, Marigold, and Beetroot

BLOEM E., SCHROETTER S., EL-KHAYAT A. S. M. \& SCHNUG E. 2011. Influence of sulphur and nitrogen supply on the pigment content of oilseed rape, marigold, and beetroot. - Phyton (Horn, Austria) 50 (2): 301-317, with 2 figures. In the past, it was shown that severe symptoms of sulphur (S) deficiency and nitrogen (N) deficiency are related to the pigment content in leaves and flowers of oilseed rape. N and S deficiency both cause chlorosis of leaves by interfering with chlorophyll biosynthesis. S-deficient flowers of oilseed rape change in colour from bright yellow to pale yellow or nearly white flowers, a phenomenon closely linked to the formation of pigments. In the present study, the impact of S and N nutrition on the synthesis of different plant pigment classes was investigated in different plants and plant organs in order to assess a possible influence of fertilisation practices on this food quality parameter. In a pot experiment with oilseed rape (Brassica napus), marigold (Calendula officinalis) and red beetroot (Beta vulgaris subsp. vulgaris) the influence of a graded N and S supply on the content of photosynthetic pigments in leaves (chlorophyll, carotenoids) and colour intensity of flowers (flavonoids and carotenoids) of oilseed rape and marigold and in tubers (betacyanin and betaxanthin) of beetroot was determined. The chlorophyll content in leaves of oilseed rape and beetroot increased with increasing N nutrition, while the N and S supply did not affect the chlorophyll content of marigold leaves. Changes in the S supply had no effect on the pigment content of beetroot. The N supply had the strongest influence on the betalain content in beetroot tubers and the colour intensity of flowers of oilseed rape and marigold. In case of oilseed rape, interactions between the S and N supply were found. The colour intensity of oilseed rape flowers increased with increasing S level, while a higher N supply reduced the pigment content.