Changes in Glucosinolate Concentrations in Brassica Crops B oleracea and B napus Throughout Growing Seasons

Abstract

Abstract:In the Iberian Peninsula, Brassica crops are grown throughout the year and may be consumed at immature stages or leaves may be harvested by 'picking-over' during plant growth. Consumption of Brassicas in Portugal is high but there is no information on the levels of glucosinolates in such material. Changes in the total and individual glucosinolate concentrations of four Brassica oleracea types (two cultivars of Portuguese cabbage, one Portuguese kale type and one hybrid white cabbage) and one Portuguese Brassica napus type were monitored throughout two growing seasons, spring/summer (SS) and summer/ winter (SW). Glucosinolates were determined between sowing and maturity corresponding to nine sampling dates in the leaves and five harvests in the heads. The main glucosinolates in B oleracea types were 3-methylsulphinylpropyl-, allyland indol-3-ylmethyl-whereas in the B napus type pent-4-enyl-, 2-hydroxybut-3-enyl-and but-3-enylglucosinolate predominated. In the leaves of B oleracea types, the highest concentration of total glucosinolates and of most of the individual glucosinolates was observed at 14 days after sowing whilst, in the heads the highest levels were noted at the start of head formation. In the B napus, the highest total and individual glucosinolate concentration was generally observed at the end of the growing season. Both for the total and for the main individual glucosinolates there were significant differences (P c 0.001) between the nine harvest dates and between growing seasons. Between the two seasons, the glucosinolate levels in SS were generally higher than in SW. A comparison of cultivars showed the hybrid cabbage to have generally higher glucosinolate levels than the Portuguese types, except for B napus.

Variation in glucosinolates in pak choi cultivars and various organs at different stages of vegetative growth during the harvest period

“…This genotypic variation in GS content in the pak choi cultivars is consistent with previous studies (He et al, 2000;Castro et al, 2004;Kim et al, 2010). The variation in GS content among the pak choi cultivars may be due to differences in their genetic backgrounds or developmental and environmental regulation (Rosa et al, 1996;Petersen et al, 2002;Brown et al, 2003;Bellostas et al, 2004;Velasco et al, 2007). GSs play an important role in plant defense systems and human nutrition.…”

“…Previous studies have shown that, whether in Brassica crops such as B. rapa, B. napus, and B. nigra, or Arabidopsis thaliana, the composition and content of GSs vary considerably among and within species and are regulated both developmentally and environmentally in various organs and tissues (Rosa et al, 1996;Petersen et al, 2002;Brown et al, 2003;Bellostas et al, 2004;Velasco et al, 2007). Investigations of GS composition and content in B. napus, A. thaliana, and Raphanus raphanistrum during development showed that plants that produce GSs commonly accumulate them in all vegetative and reproductive parts throughout development (ClossaisBesnard and Larher, 1991;Brown et al, 2003;Malik et al, 2010).…”

Glucosinolate profiling of seeds and sprouts of B. oleracea varieties used for food

“…When glucosinolates and myrosinases come into contact in the presence of water, e.g. during processing, cutting or chewing of the tissue, glucosinolates are transformed into biologically active products (Brown and Morra, 1997;Rosa et al, 1996). These glucosinolate breakdown products have different structures and physico-chemical properties depending upon the parent glucosinolate and the conditions under which the transformation takes place (Bjergegaard et al, 1994).…”

Effects of Glucosinolates and Flavonoids on Colonization of the Roots of Brassica napus by Azorhizobium caulinodans ORS571

“…However, it is important to note that variation in glucosinolate concentrations in tissues of plants of the same variety is frequently observed and is influenced by growth conditions (19,29). The stage of plant maturation also influences tissue concentrations of glucosinolates (27), 10-fold differences sometimes being observed during the first few weeks of growth (17). Frequently, considerable variation is also encountered between tissues in the same plant (9).…”