Abstract:

Polycyclic Aromatic Hydrocarbon (PAHs) have a negative impact on the growth and development of vegetables, leading to decreased yield and quality, which in turn can pose a risk to human health via the food chain. This paper presents the results of greenhouse pot experiments that aimed to assess the impact of different pyrene concentrations (0, 50, 100, 200, 400 mg∙kg⁻¹) on pakchoi (Brassica chinensis L.), carrot (Daucus carota L.) and tomato (Solanum lycopersicum L). Parameters such as growth indexes (root length, shoot length, fresh weight), chlorophyll content, quality indexes (soluble protein, soluble sugar, vitamin C), and pyrene concentration in different parts of the vegetables were determined. The tolerance and accumulation characteristics of the three types of vegetables were compared under pyrene treatments. The aims of this study were to identify vegetable varieties with high tolerance and low accumulation capacity to pyrene. The results showed that 1) different concentrations of pyrene significantly reduced the growth parameters of all three vegetables and inhibited their photosynthesis. The tolerance of the three vegetables to pyrene followed the order: tomato>pakchoi>carrot. 2) With respect to vegetable quality, the soluble protein content of pakchoi and carrot decreased with the increase of pyrene concentration. In contrast, the soluble protein content of tomato initially increased and then decreased. The soluble sugar content of all the three vegetables decreased, and the soluble sugar content of pakchoi, carrot and tomato decreased by 21.6%, 36.2% and 19.1%, respectively, under 400 mg∙kg⁻¹ pyrene treatment. Pyrene treatments also stimulated the production of vitamin C in the vegetables, with the highest increase observed in tomato. Among the three vegetables, tomato demonstrated the least sensitivity to pyrene-induced changes in quality indexes. 3) Regarding pyrene accumulation, significant differences were observed in its concentrations among different tissues within each vegetable type. However, root accumulation was consistently the most prominent. Furthermore, pyrene accumulation increased significantly with the increase of pyrene concentration. The bioconcentration factors of the edible parts of the three vegetables followed the order: carrot (0.162)>pakchoi (0.0463)>tomato (1.32×10⁻³). Furthermore, tomato demonstrated the smallest translocation factor for pyrene among the three vegetables. Based on these comprehensive results, it is evident that tomato possesses high resistance to pyrene pollution in soil. It not only boasts superior quality but also exhibits low ability to accumulate pyrene in its edible parts. Additionally, tomato exhibits the weakest ability to transport pyrene from its roots to its aboveground organs. Therefore, tomato is more suitable for planting on pyrene-contaminated farmland soil compared to pakchoi and carrot. The findings of this study can serve as valuable references for vegetable cultivation in contaminated soil.

Key words: pyrene, vegetables, growth, quality, accumulation and translocation, variety difference

摘要：

多环芳烃会影响蔬菜的生长发育，导致其产量和品质降低，最终通过食物链危害人体健康。通过温室盆栽土培试验，测定不同质量分数（0、50、100、200、400 mg∙kg⁻¹）芘作用下小白菜（Brassica chinensis L.）、胡萝卜（Daucus carota L.）、番茄（Solanum lycopersicum L.）的生长指标（根长、株高、鲜质量）、叶绿素质量分数、品质指标（可溶性蛋白、可溶性糖、维生素C）和蔬菜各部位芘质量分数等，对芘处理下不同种类蔬菜的耐性和累积特性进行了比较研究，筛选出高耐芘性和低富集能力的蔬菜品种。结果表明，1）芘处理降低了3种蔬菜的生长参数，抑制了蔬菜的光合作用，3种蔬菜耐芘能力大小顺序为：番茄>小白菜>胡萝卜。2）蔬菜品质方面，小白菜和胡萝卜可溶性蛋白随土壤芘质量分数的升高而降低，番茄可溶性蛋白表现为先增加后减少；小白菜、胡萝卜和番茄可溶性糖质量分数均降低且400 mg∙kg⁻¹芘处理下分别降低了21.6%、36.2%和19.1%；芘处理刺激了蔬菜维生素C的生成，其中番茄维生素C质量分数增幅最大，3种蔬菜中番茄品质受芘影响最小。3）不同种类蔬菜各部位芘质量分数存在显著差异，但均以根系积累为主，积累量随芘质量分数的升高而增加；3种蔬菜可食部位芘富集系数表现为胡萝卜 (0.162)>小白菜 (0.0463)>番茄 (1.32×10⁻³)，并且3种蔬菜中番茄芘转运系数最小。综合研究表明，3种蔬菜中番茄耐土壤芘污染的能力高，品质最好，可食部位富集芘能力低，芘从根部向地上各器官转运的能力最弱，与小白菜和胡萝卜相比更适合在芘污染的农田土壤上种植。研究结果可为污染土壤蔬菜种植提供参考。

关键词: 芘, 蔬菜, 生长, 品质, 积累与转运, 品种差异