不同品种辣椒镉亚细胞分布和化学形态特征差异

前期试验对91个辣椒品种资源进行筛选,以高积Cd型品种(X55)、中积Cd型品种(27)和低积Cd型品种(17)各一份,采用盆栽试验研究不同镉水平(0、5和10 mg·kg-1Cd)下3个品种辣椒Cd转移和富集能力差异以及镉在果实中亚细胞分布和形态特征.结果表明,Cd胁迫下,辣椒地上部干重在种间表现为品种X55 17 27.果实Cd转移系数在同一Cd水平下均表现为品种17 27或X55.辣椒果实各亚细胞组分中Cd含量在种间表现为品种27 17 X55.辣椒根、茎、叶和果各亚细胞组分中Cd含量均表现为细胞壁(F1)细胞器(F2)细胞可溶性组分(F3),Cd被限制在细胞壁中,在辣椒Cd解毒机制和抗性中起重要作用. 3个品种辣椒果实各Cd化学形态含量随Cd处理水平的增加而增加,且大小均表现为CdNaClCdHAC CdR CdHCl CdW CdE.辣椒果实中的CdNaCl和CdHAC占比例较大可能是辣椒降低Cd生物毒性的一种防御机制.

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 Cd_NaCl > Cd_HAC > Cd_R > Cd_HCl > Cd_W > Cd_E. Cd_NaCl and Cd_HAC account for a large proportion of Cd in pepper fruits, which may be an important defense mechanism for reducing the biological toxicity of Cd.