Cadmium (Cd) pollution ranks first in soils (7.0%) and microplastics usually have a significant adsorption capacity for it, which could pose potential threats to agricultural production and human health. However, the joint toxicity of Cd and microplastics on crop growth remains largely unknown. In this study, the toxic effects of Cd²⁺ and two kinds of microplastic leachates, polyvinyl chloride (PVC) and low-density polyethylene (LDPE), on wheat seed germination and seedlings’ growth were explored under single and combined conditions. The results showed that Cd²⁺ solution and two kinds of microplastic leachates stimulated the wheat seed germination process but inhibited the germination rate by 0–8.6%. The combined treatments promoted wheat seed germination but inhibited the seedlings’ growth to different degrees. Specifically, the combination of 2.0 mg L⁻¹ Cd²⁺ and 1.0 mgC L⁻¹ PVC promoted both seed germination and seedlings’ growth, but they synergistically increased the antioxidant enzyme activity of seedlings. The toxicity of the PVC leachate to wheat seedlings was stronger than LDPE leachate. The addition of Cd²⁺ could alleviate the toxicity of PVC leachate on seedlings, and reduce the toxicity of LDPE leachate on seedlings under the same concentration class combinations but aggravated stress under different concentration classes, consistent with the effect on seedlings’ growth. Overall, Cd²⁺, PVC, and LDPE leachates have toxic effects on wheat growth, whether treated under single or combined treatments. This study has important implications for the joint toxicity of Cd²⁺ solution and microplastic leachates in agriculture.

Graphical abstract

中文翻译：

---

镉（II）和微塑料渗滤液对小麦种子萌发和幼苗生长的联合毒性

镉（Cd）污染在土壤中排名第一（7.0%），微塑料通常对其具有显着的吸附能力，可能对农业生产和人类健康构成潜在威胁。然而，镉和微塑料对作物生长的联合毒性仍然很大程度上未知。本研究探讨了Cd ²⁺和两种微塑料浸出液聚氯乙烯（PVC）和低密度聚乙烯（LDPE）在单一和组合条件下对小麦种子萌发和幼苗生长的毒性作用。结果表明，Cd ²⁺溶液和两种微塑料浸出液刺激了小麦种子的发芽过程，但抑制了发芽率0%~8.6%。联合处理促进了小麦种子的萌发，但不同程度地抑制了幼苗的生长。具体而言，2.0 mg L ^-1 Cd ²⁺和1.0 mgC L ^-1 PVC组合促进种子萌发和幼苗生长，并协同提高幼苗的抗氧化酶活性。 PVC渗滤液对小麦幼苗的毒性强于LDPE渗滤液。 Cd ²⁺的添加可以减轻PVC渗滤液对幼苗的毒性，在相同浓度组组合下降低LDPE渗滤液对幼苗的毒性，但不同浓度组下胁迫加剧，与对幼苗生长的影响一致。总体而言，无论是单一处理还是联合处理，Cd ²⁺、PVC 和 LDPE 渗滤液对小麦生长都有毒性作用。这项研究对于农业中Cd ²⁺溶液和微塑料渗滤液的联合毒性具有重要意义。

图形概要