Zhuang Xiaolei, Wan Huixue, Wang Hongyu, Qin Sijun, He Jiali, Lyu Deguo
College of Horticulture, Shenyang Agricultural University, Shenyang, Liaoning, China.
Key Lab of Fruit Quality Development and Regulation of Liaoning Province, Shenyang Agricultural University, Shenyang, Liaoning, China.
Front Plant Sci. 2023 Jun 2;14:1188241. doi: 10.3389/fpls.2023.1188241. eCollection 2023.
Cadmium (Cd) is a nonessential element and highly toxic to apple tree. However, Cd accumulation, translocation and tolerance in apple trees planted in different soils remain unknown. To investigate soil Cd bioavailability, plant Cd accumulation, physiological changes as well as gene expression patterns in apple trees grown in five different soils, 'Hanfu' apple seedlings were planted in orchard soils collected from Maliangou village (ML), Desheng village (DS), Xishan village (XS), Kaoshantun village (KS) and Qianertaizi village (QT), and subjected to 500 μM CdCl for 70 d. Results showed that soils of ML and XS had higher content of organic matter (OM), clay and silt, and cation exchange capacity (CEC) but lower sand content than the other soils, thereby reduced Cd bioavailability, which could be reflected by lower concentrations and proportions of acid-soluble Cd but higher concentrations and proportions of reducible and oxidizable Cd. The plants grown in soils of ML and XS had relatively lower Cd accumulation levels and bio-concentration factors than those grown in the other soils. Excess Cd reduced plant biomass, root architecture, and chlorophyll content in all plants but to relatively lesser degree in those grown in soils of ML and XS. The plants grown in soils of ML, XS and QT had comparatively lower reactive oxygen species (ROS) content, less membrane lipid peroxidation, and higher antioxidant content and enzyme activity than those grown in soils of DS and KS. Transcript levels of genes regulating Cd uptake, transport and detoxification such as , , , , , , , , , and displayed significant differences in roots of plants grown in different soils. These results indicate that soil types affect Cd accumulation and tolerance in apple plants, and plants grown in soils with higher OM content, CEC, clay and silt content and lower sand content suffer less Cd toxicity.
镉（Cd）是一种非必需元素，对苹果树具有高毒性。然而，不同土壤中种植的苹果树对镉的积累、转运和耐受性仍不清楚。为了研究五种不同土壤中生长的苹果树的土壤镉生物有效性、植物镉积累、生理变化以及基因表达模式，将‘寒富’苹果幼苗种植在从马连沟村（ML）、德胜村（DS）、西山村（XS）、靠山屯村（KS）和前二台子村（QT）采集的果园土壤中，并施加500 μM CdCl₂ 70天。结果表明，ML和XS土壤的有机质（OM）、黏土和粉砂含量以及阳离子交换容量（CEC）较高，但砂含量低于其他土壤，从而降低了镉的生物有效性，这可通过酸溶性镉的浓度和比例较低但可还原和可氧化镉的浓度和比例较高来体现。在ML和XS土壤中生长的植物比在其他土壤中生长的植物具有相对较低的镉积累水平和生物富集系数。过量的镉降低了所有植物的生物量、根系结构和叶绿素含量，但在ML和XS土壤中生长的植物中降低程度相对较小。与在DS和KS土壤中生长的植物相比，在ML、XS和QT土壤中生长的植物具有相对较低的活性氧（ROS）含量、较少的膜脂过氧化以及较高的抗氧化剂含量和酶活性。调节镉吸收、转运和解毒的基因如[此处原文缺失相关基因名称]等的转录水平在不同土壤中生长的植物根系中表现出显著差异。这些结果表明，土壤类型影响苹果植株对镉的积累和耐受性，生长在有机质含量、CEC、黏土和粉砂含量较高且砂含量较低的土壤中的植物遭受的镉毒性较小。
