Cabbage Yield and Glucosinolate Concentrations as Affected by Nitrogen and Sulfur Fertility

Abstract

<jats:p>Glucosinolates are a class of nitrogen (N) and sulfur (S) containing compounds shown to have cancer-preventing properties in animal models and widely found in cruciferous plants. The overall objective of this study was to determine whether N and S fertility affects glucosinolate concentrations in cabbage (<jats:italic>Brassica oleracea</jats:italic> L. Capitata group). Field studies on a sandy soil low in available N and S were conducted over a 2-year period with both green (`Grand Slam') and red (`Vorox') cabbage cultivars. Treatments evaluated each year were the interactive effects of N (125 and 250 kg·ha<jats:sup>–1</jats:sup>) and S (0, and 110 kg·ha<jats:sup>–1</jats:sup>) fertilizer application. Yield of both cabbage cultivars increased with increasing N and S in the second year of the study, but not in the first. Tissue N concentrations in heads at harvest increased with N application and tissue S concentrations increased with S application. When S was not applied, tissue S decreased significantly as N rate increased, while N rate had no effect on tissue S concentrations when S was applied. The dominant glucosinolate detected in both cabbage cultivars was glucobrassicin, with indole forms accounting for about 80% of the total glucosinolates regardless of treatment. Tissue N was negatively correlated and tissue S and S to N ratio were positively correlated with total glucosinolate concentration, although all correlations were generally weak (<jats:italic>r</jats:italic><jats:sup>2</jats:sup> &lt; 0.5). Total glucosinolates and glucobrassicin concentrations were maximized in both cultivars at the low N and high S application rates. Except for sinigrin in one of the 2 years, all glucosinolates detected were higher in Vorox than in `Grand Slam'. Based on these results, glucosinolates in cabbage can be manipulated by cultural management practices as well as genetics.</jats:p>

Effects of Organic and Waste-Derived Fertilizers on Yield, Nitrogen and Glucosinolate Contents, and Sensory Quality of Broccoli (Brassica oleracea L. var. italica)

“…The availability of N and S and the N:S ratio has previously been shown to influence the content of GLS. 18,24,25,42 In the present study neither total N supply, estimated as potentially plant-available N, nor N:S ratio correlated with total GLS content; however, there was a positive correlation between total GLS content in broccoli and S content in fertilizer materials. The high total GLS level in broccoli fertilized with SS and MF, which had the highest S content among the fertilizer materials, and the low level of total GLS in broccoli fertilized with SM with low S content indicate that S supply might be more important for the total GLS content than N supply and N:S ratio at the current fertilizer rates.…”

Glucosinolates in Brassica foods: bioavailability in food and significance for human health

“…Kim et al (2002) found that glucosinolate content from the edible parts of B. rapa is strongly affected by nitrogen and sulphur applications. This was also stated by Rosen et al (2005) who showed that total glucosinolates and glucobrassicin content were maximized in cabbage cultivars grown at low nitrogen and high sulphur application rates.…”

Minimal nitrogen and water use in horticulture: Effects on quality and content of selected nutrients

“…The influence of N and sulphur (S) on glucosinolate content in broccoli has been widely studied, but similar studies are lacking for cabbage and cauliflower (Table 1), with the exception of Rosen, Gardener, Hecht, Carmella, and Kenney (2005). Glucosinolate synthesis in broccoli requires optimal (i.e.…”

“…Once S supply is adequate, however, minimal N applications resulted in highest glucoraphanin content in broccoli (Table 1) (Jones et al, 2007), but N application rates that optimized glucoraphanin content in broccoli resulted in a significant decline in head weight (Jones et al, 2007) In a study with higher N application rates (50-600 kg ha À1 ), Omirou et al (2009) found glucoraphanin content in broccoli florets was maximized with a mid-range N application of 250 kg ha À1 . Growth stress caused by limited N also resulted in enhanced glucosinolate synthesis in pak choi (Shattuck & Wang, 1994), watercress (Kopsell et al, 2007a(Kopsell et al, , 2007b, and cabbage (Rosen et al, 2005) (Table 1). Jones et al (2007) postulated that poor N availability in broccoli florets may indirectly result in an increased availability of methionine for glucosinolate production, as suggested by Dick-Hennes and Buning-Pfaue (1992).…”