Screening of Leafy Vegetable Varieties with Low Lead and Cadmium Accumulation Based on Foliar Uptake

Abstract

Leafy vegetables cultivated in kitchen gardens and suburban areas often accumulate excessive amounts of heavy metals and pose a threat to human health. For this reason, plenty of studies have focused on low accumulation variety screening. However, identifying specific leafy vegetable varieties according to the foliar uptake of air pollution remains to be explored (despite foliar uptake being an important pathway for heavy-metal accumulation). Therefore, in this study, the lead (Pb) and cadmium (Cd) contents, leaf morphology, and particle matter contents were analyzed in a micro-area experiment using 20 common vegetables. The results show that the Pb content in leaves ranged from 0.70 to 3.86 mg kg−1, and the Cd content ranged from 0.21 to 0.99 mg kg−1. Atmospheric particles were clearly scattered on the leaf surface, and the particles were smaller than the stomata. Considering the Pb and Cd contents in the leaves and roots, stomata width-to-length ratio, leaf area size, enrichment factor, and translocation factor, Yidianhongxiancai, Qingxiancai, Baiyuanyexiancai, Nanjingjiangengbai and Sijixiaobaicai were recommended for planting in kitchen gardens and suburban areas as they have low accumulation characteristics. Identifying the influencing factors in the accumulation of heavy metals in vegetables through foliar uptake is important to help plant physiologists/environmentalists/policy makers to select suitable varieties for planting in air-polluted areas and thus reduce their threat to human health.

Assessment of Cadmium Concentrations in Foodstuffs and Dietary Exposure Risk Across China: A Metadata Analysis

“…After entering the root cortex cells, Cd forms stable macromolecular complexes or insoluble organic macromolecules by combing with proteins, polysaccharides, ribose, and nucleic acids in the roots (Li et al 2008). In addition, the concentrations of Cd in leafy vegetables increased due to deposition and adhesion of atmospheric particulate pollutants on the leaf surface (Xu et al 2022). Song et al studied Cd concentrations in vegetables from 31 provinces in China, and the results showed that the order of Cd concentration was leafy vegetables > root and stalk vegetables > fruit vegetables (Song et al 2017).…”

Comparative assessment of the heavy metal phytoextraction potential of vegetables from agricultural soils: A field experiment

“…It is hypothesized that vegetable species differ greatly in their ability to uptake and accumulate heavy metals from the soils, even among cultivars and varieties within the same species [ [22] , [23] , [24] ]. Therefore, this study aims to investigate the uptake of ten heavy metals in different plant parts of several vegetable species with high biomass production for its potential phytoremediation application.…”

Content of Cadmium and Nickel in Soils and Assimilatory Organs of Park Woody Species Exposed to Polluted Air

“…For example, the distribution of Cd in different growth stages of Tlaspi caerulescens varied according to the plant organ [13]. Xu et al [14] found that leafy vegetables cultivated in gardens and suburban areas of southern China contain excessive amounts of Cd (0.21 to 0.99 mg kg −1 ) and could therefore threaten human health.…”