Submitted to: BARC Poster Day
Publication Type: Abstract Only
Publication Acceptance Date: March 13, 2010
Publication Date: April 14, 2010
Citation: Zia, M.H., Codling, E.E. 2010. Differences among cabbage (Brassica oleracea L. var capitata) genotypes for Cd uptake and accumulation in fruiting portion and possible inhibition through use of silicon. BARC Poster Day.
Soils may become progressively enriched with cadmium as a consequence of industrial activities, fertilization, and waste disposal. The current widespread interest in Cd uptake and translocation arises not only from its toxicity to plants, but also from the harmful health effects of its dietary intake. In this study, 12 cultivars of cabbage widely grown on Cd polluted soils in Pakistan were grown in hydroponics across 0.25, 0.50, and 0.75 µM Cd levels. Visible Cd toxicity symptoms (chlorosis and white spots) were observed at all Cd levels on all cultivars, except for cultivar Laurent, which depicted stunted growth only. Significant differences among cabbage genotypes for Cd accumulation within roots, leaves and head portions were observed. On an overall basis, it appeared that DC 14, Green Rise and Green Burger cultivars of cabbage are hypo-accumulator of Cd in edible portion of cabbage followed by Saint and Laurent when tested across three levels of Cd. On the other hand, Asha and CHX-122 cultivars seemed relatively hyper-accumulator of Cd in their edible portion followed by Golden Cabbage, across all levels of Cd. Increasing Cd supply significantly increased the Cd concentration of cabbage plants in this study and irrespective of cultivar, cadmium was accumulated in the roots in much higher amounts than in the shoot and head portions. Root analysis results revealed that silicon (Si) significantly reduced Cd uptake with each of its incremental dose (R2 0.75). At the same time, incremental addition of Si (beyond 0.4-0.6 mM Si) also caused a smooth decrease in root biomass of cabbage plants possibly through osmotic effect due to high EC and/or excess of accompanying Na ions. It is suggested that 0.4 mM Si could minimize Cd entry to cabbage roots without any negative effects on root biomass. Based on above findings, DC 14 cultivar seems to be the most promising one regarding exclusion of Cd within its edible portion as well as having higher relative tolerance, therefore, yielding lowest Cd contents within edible portion of cabbage. It can be inferred from present study that selection of cabbage genotypes may add to safer crop production on Cd contaminated sites but response of any particular genotype may vary when grown across various levels of Cd in rooting medium.