Relationship between biomass, seed components and seed Cd concentration in various peanut (Arachis hypogaea L.) cultivars grown on Cd-contaminated soils

Peanuts (Arachis hypogaea L.) exhibit high genotypic variations in seed Cd accumulation, but the mechanism remains unclear. This study aimed to reveal the main factors that determine Cd concentration in peanut seeds. The biomasses and Cd accumulation in plant tissues as well as the Cd distribution in the seeds of 15 peanut cultivars were analyzed in a pot experiment at 4 mg kg(-1) Cd (treatment) and 0 mg kg(-1) Cd (control). Peanuts exhibited large variations among cultivars in terms of Cd accumulation and distribution at the whole-plant and seed levels. The peanut cultivars were divided into three groups based on [Cd](embryos) as follows: (i) high Cd accumulators (Zhenghong 3 and Haihua 1), (ii) low Cd accumulators (Qishan 208, Luhua 8, and Yuhua 15), and (iii) intermediate Cd accumulators (10 remaining cultivars). [Cd](embryos) was significantly correlated with [Cd](testae) and [Cd](oils) at control conditions, whereas in the 4 mg kg(-1) Cd treatment, [Cd](embryos) was negatively, correlated with plant biomass, total Cd and its proportion in vegetative organs, and seed oil contents. [Cd](embryos), was positively correlated with protein contents, [Cd](oils), and proportion of Cd in protein extracts at 4 mg kg(-1) Cd treatments. The attenuation of Cd by high biomass of vegetative tissues and Cd-binding proteins in seeds mainly determined the Cd concentration in peanut seeds. (C) 2014 Elsevier Inc. All rights reserved.