[Differences in the Cadmium-Enrichment Capacity and Subcellular Distribution and Chemical Form of Cadmium in Different Varieties of Pepper].

In a preliminary experiment, 91 pepper varieties were screened, and one variety each with high Cd accumulation (X55), medium Cd accumulation (Daguo 99), and low Cd accumulation (Luojiao 318) were selected to study the effect of different cadmium levels (0, 5, and 10 mg·kg-1 Cd) on cadmium migration and enrichment ability, and its subcellular distribution and chemical form. The results showed that under the stress of Cd, shoot dry weight of pepper plants was in the order X55>17>27. At the same level of Cd, the Cd transfer coefficient of fruit was 17>27 and X55. Cadmium concentrations in each subcellular component of the pepper fruits were 27 > 17 > X55. Cadmium concentration in subcellular component of the roots, stems, leaves, and fruits of the pepper plants was in order of cell wall (F1) > organelle (F2) > cell soluble component (F3). Cadmium was limited in cell wall and plays an important role in detoxification mechanism and resistance of Cd in pepper plants. The morphological content of various Cd forms in the pepper fruits of the three varieties increased with the increase of Cd treatment level, in the order CdNaCl > CdHAC > CdR > CdHCl > CdW > CdE. CdNaCl and CdHAC account for a large proportion of Cd in pepper fruits, which may be an important defense mechanism for reducing the biological toxicity of Cd.