郭琳琳, 俎敬美, 王晶晶, 谌柄旭. 聚苯乙烯纳米塑料与铅胁迫对菠菜种子萌发和幼苗生长的影响[J]. 中国生态农业学报(中英文), 2023, 31(6): 967−975. DOI: 10.12357/cjea.20220721
引用本文: 郭琳琳, 俎敬美, 王晶晶, 谌柄旭. 聚苯乙烯纳米塑料与铅胁迫对菠菜种子萌发和幼苗生长的影响[J]. 中国生态农业学报(中英文), 2023, 31(6): 967−975. DOI: 10.12357/cjea.20220721
GUO L L, ZU J M, WANG J J, CHEN B X. Effects of the combination of polystyrene nanoplastics and lead on seed germination and seedling growth of spinach (Spinacia oleracea)[J]. Chinese Journal of Eco-Agriculture, 2023, 31(6): 967−975. DOI: 10.12357/cjea.20220721
Citation: GUO L L, ZU J M, WANG J J, CHEN B X. Effects of the combination of polystyrene nanoplastics and lead on seed germination and seedling growth of spinach (Spinacia oleracea)[J]. Chinese Journal of Eco-Agriculture, 2023, 31(6): 967−975. DOI: 10.12357/cjea.20220721

聚苯乙烯纳米塑料与铅胁迫对菠菜种子萌发和幼苗生长的影响

Effects of the combination of polystyrene nanoplastics and lead on seed germination and seedling growth of spinach (Spinacia oleracea)

  • 摘要: 微塑料作为一种新型环境污染物, 对生物体和自然环境的负面影响受到广泛关注, 而微塑料与重金属复合污染对于蔬菜作物影响的研究却少有报道。为探讨聚苯乙烯纳米塑料(PSNPs)、铅(Pb)及其复合污染对菠菜种子萌发和幼苗生长的影响, 研究了菠菜种子和幼苗分别暴露于200~1600 mg∙L−1 PSNPs、5~100 mg∙L−1 Pb及其复合溶液后发芽率、发芽势、发芽指数、根长、芽长, 超氧化物歧化酶(SOD)和过氧化物酶(POD)活性, 及可溶性蛋白含量的变化。结果表明, 相比于空白对照组, 单一PSNPs (≥400 mg∙L−1)胁迫会显著降低种子的发芽率、发芽势和发芽指数, 低浓度的PSNPs (200 mg∙L−1)促进菠菜种子根、芽的伸长, 高浓度(1600 mg∙L−1)的PSNPs胁迫显著抑制SOD、POD的活性, 虽然不同浓度的PSNPs均会增加可溶性蛋白的含量, 但仅在400 mg∙L−1和800 mg∙L−1浓度组显著高于对照组。单一的Pb (≥25 mg∙L−1)胁迫抑制菠菜种子的萌发, 降低SOD的活性, 而提高POD活性和可溶性蛋白的含量。PSNPs-Pb的复合污染表明, 相比于Pb单一胁迫, PSNPs与Pb复合污染对菠菜种子的萌发起拮抗作用, 降低了Pb单独胁迫对种子萌发的抑制作用; 而PSNPs-Pb复合污染对菠菜幼苗的影响主要是低浓度(200 mg∙L−1) PSNPs与Pb二者表现为协同作用, 高浓度(800 mg∙L−1) PSNPs与Pb复合污染加重了对菠菜幼苗的毒害, 主要表现为SOD和POD活性的显著降低。研究表明, PSNPs能够缓解Pb对菠菜种子萌发的抑制作用; 低浓度PSNPs (200 mg∙L−1)与Pb对菠菜幼苗的影响表现为协同作用, 而高浓度(800 mg∙L−1) PSNPs与Pb对菠菜幼苗主要表现为拮抗作用。

     

    Abstract: Microplastics (MPs) are a new environmental pollutant that has attracted widespread attention because of their negative effects on organisms and the environment. However, studies on the impact of co-contamination of MPs and heavy metals on vegetables are limited. To explore the effects of polystyrene nanoplastics (PSNPs), lead (Pb), and their co-contamination on seed germination and seedling growth of spinach, we investigated the germination rate, germination vigor and germination index of seeds; root length, shoot length, superoxide dismutase (SOD) and peroxidase (POD) activities, and soluble protein content of seedlings of spinach (Spinacia oleracea), which were exposed to the control, PSNPs (200, 400, 800, and 1600 mg·L1) and Pb (5, 25, 50, and 100 mg·L1) and their combination (Pb 5 mg·L1 + PSNPs 200 mg·L1, Pb 5 mg·L1 + PSNPs 800 mg·L1, Pb 50 mg·L1 + PSNPs 200 mg·L1, and Pb 50 mg·L1 + PSNPs 800 mg·L1). Single effects of PSNPs (≥400 mg·L1) significantly decreased the germination rate, vigor, and index; however, there was no significant difference between 200 mg·L1 PSNPs and the control for those indicators. PSNPs at low concentrations (200 mg·L1) promoted the length of roots and shoots, but other PSNPs concentrations (≥400 mg·L1) had no significant impacts on roots and shoots. SOD activity was inhibited at a high concentration (≥800 mg·L1) of PSNPs, and the POD activity was induced when PSNPs ≤800 mg·L1, whereas POD was inhibited at the high PSNPs concentration (1600 mg·L1). The soluble protein content in spinach seedlings under different concentrations of PSNPs increased, but the content was significantly higher than the control at 800 mg·L1 PSNPs. Under Pb exposure alone, germination rate, vigor, and index decreased. Further, treatments with low Pb concentration (5 mg·L1) increased root and shoot length, whereas high concentrations (≥25 mg·L1) reduced them. Moreover, SOD inhibition and POD induction were observed following Pb treatment. With increased Pb concentration, the soluble protein content of spinach seedlings decreased firstly at low concentration (5 mg·L1) and then increased. Compared with single Pb treatment, combined effects of PSNPs and Pb were generally antagonistic to seed germination. For example, PSNPs weakened the promotion effects of low Pb concentration (5 mg∙L1), inhibited the growth of root and shoot of spinach seedlings, and alleviated the inhibitory effects of high Pb concentrations (50 mg∙L1) on seedling root and shoot growth. Low concentration (200 mg·L1) of PSNPs and Pb showed synergistic effects in spinach seedlings, such as enhanced induction effects of Pb on POD activity. The co-contamination of PSNPs at high concentrations (800 mg·L1) and Pb caused greater damage to seedlings, and the activities of SOD and POD decreased significantly. These results showed that PSNPs alleviated the inhibitory effects of Pb on spinach seed germination. Low concentrations of PSNPs (200 mg∙L1) and Pb mainly showed synergistic effects, whereas high concentrations of PSNPs (800 mg∙L1) and Pb mainly showed antagonistic effects. This study demonstrates that co-contamination of PSNPs and Pb has significant toxicity on seed germination and seedling growth, affecting the antioxidant system and soluble proteins of spinach. In conclusion, coexisting PSNPs can alter the bioavailability of Pb and plant performance. Our findings can help evaluate the individual and comprehensive toxicity of microplastics and heavy metals in vegetable crops.

     

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