Inter- and Intraspecific Variations of Cadmium Accumulation of 13 Leafy Vegetable Species in a Greenhouse Experiment

Abstract

Leafy vegetables are among the crop species that are most vulnerable to heavy metal pollution. This study investigated inter- and intraspecific variations of cadmium accumulation in 13 species with a total of 39 cultivars of leafy vegetables under two levels of soil Cd stress (1.5 and 7.7 mg kg (-1)). Intraspecific variations of shoot biomass and Cd concentration of the tested leafy vegetables were significantly larger than interspecific variations under both Cd treatments and were also more significantly correlated between two Cd stress levels when grouped by cultivar than grouped by species. These results indicate that cultivar is a more reliable taxa level for screening pollutant-safe leafy vegetables than species. Any screening for pollutant hypoaccumulator species, or other similar species-based concepts, without considering intraspecific variation should be avoided.

Variations in cadmium and nitrate co-accumulation among water spinach genotypes and implications for screening safe genotypes for human consumption

“…Water spinach tolerates high Cd and nitrate stress relatively well. The results were consistent with previous studies (Wang et al, 2007). Since there is no visible symptom of toxicity when water spinach is grown in Cd and nitrate co-contaminated soils, the potential health risk may be high from inadvertently consuming contaminated water spinach.…”

“…The accumulation of Cd in plants varies greatly not only among plant species but also among genotypes or cultivars within the same species (Yu et al, 2006;Liu et al, 2007;Wang et al, 2007;Martin et al, 2012). The results of the present study showed that different genotypes of water spinach had different Cd retention abilities, resulting in different Cd accumulations.…”

Lead accumulation in different Chinese cabbage cultivars and screening for pollution-safe cultivars

“…Under Pb treatments 500 and 1500 mg kg À1 , Pb concentrations in 60% (18/30) and 86.7% (26/30) of the tested cabbage cultivars exceeded 2.0 mg kg À1 DW, respectively. Since cabbage shoots contain 90% water (the average value in this study), most of them exceeded 0.2 mg kg À1 fresh weight (FW), the maximum permissible concentration (MPC) for Pb in vegetables (National Food Hygiene Standard of China, NFHSC) (Yu et al, 2006;Wang et al, 2007). Therefore, in this study, shoot Pb concentration with less than 2.0 mg kg À1 DW should be considered as a critical standard for screening Pb-PSCs among different cabbage cultivars.…”

“…The maximum permissible concentration (MPC) for Pb in vegetables for safe consumption is 0.2 mg kg À1 fresh weight (FW) according to NFHSC (GB14935-94) (Yu et al, 2006;Wang et al, 2007).…”

“…cultivars accumulate specific pollutants at a level low enough for safe consumption even when grown in contaminated soil (Yu et al, 2006;Wang et al, 2007). The concept of PSCs is grounded on the basis of prior literatures, which have shown that significant difference occurs in the uptake and distribution of trace elements among plant species and among cultivars within species (Yu et al, 2006;Grant et al, 2008).…”