College of Natural Resources and Environment, Northwest A&F University, Yangling, 712100, Shaanxi, PR China; Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, Ministry of Agriculture, Yangling, 712100, Shaanxi, PR China.
College of Natural Resources and Environment, Northwest A&F University, Yangling, 712100, Shaanxi, PR China; Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, Ministry of Agriculture, Yangling, 712100, Shaanxi, PR China.
Ecotoxicol Environ Saf. 2019 Nov 15;183:109567. doi: 10.1016/j.ecoenv.2019.109567. Epub 2019 Aug 20.
Polycyclic aromatic hydrocarbons (PAHs) are universal organic pollutants in the agro ecosystems in China, therefore, it is important to understand the uptake and accumulation of PAHs in crops growing on PAHs contaminated soils for human health risk assessments. Water management is a common practice to maintain high grain yields during wheat production. However, the effects of soil water content on the accumulation and translocation of PAHs in wheat are still not clear. The main objectives of the present study were to investigate the effects of soil water content on the accumulation of three selected PAHs (ΣPAHs, phenanthrene, anthracene and pyrene) in wheat during whole plant growth stage and on translocation or remobilization of ΣPAHs from vegetative tissues to wheat grains. Winter wheat (Triticum aestivum cv. Xiaoyan22) were grown on ΣPAHs spiked soils maintaining 80%, 60% or 40% water-holding capacity during the whole plant growth stage. Plant samplings were performed at jointing, anthesis or maturity stage, respectively. The present study showed that grain yield and biomass of the crop increased with soil water content increasing. Transpiration rate of wheat leaf under 80% and 60% water-holding capacity treatments was significantly (p < 0.05) higher than that under 40% water-holding capacity treatment at both anthesis and filling stage. Soil water content and plant growth stage had significant (p < 0.0001) effects on concentrations of phenanthrene, anthracene and pyrene in winter wheat. When exposed to 0, 15, 60, and 150 mg kg ΣPAHs in soils, ΣPAHs concentrations in the grains under 60% water-holding capacity treatment were 46.6%, 69.9%, 89.5% and 81.7% of those under 80% water-holding capacity treatment, respectively. The highest concentrations of ΣPAHs in the crop were recorded at anthesis stage. The distribution of PAHs in different tissues of wheat varied among different soil water treatments and plant growth stages. The present study indicated that optimizing soil water content during winter wheat production could apparently reduce concentrations of ΣPAHs in grains via influence root uptake of ΣPAHs and translocation of ΣPAHs from stem or leaf into grain, suggesting the potential of water management to cope with PAHs contamination in crops growing on PAHs contaminated soils.
多环芳烃（PAHs）是中国农业生态系统中普遍存在的有机污染物，因此，了解 PAHs 污染土壤上作物对 PAHs 的吸收和积累对于人类健康风险评估非常重要。水管理是维持小麦生产高产量的常用方法。然而，土壤含水量对小麦中 PAHs 积累和迁移的影响尚不清楚。本研究的主要目的是研究土壤含水量对整个植物生长阶段小麦中三种选定 PAHs（ΣPAHs、菲、蒽和芘）积累的影响，以及 ΣPAHs 从营养组织向小麦籽粒的迁移或再移动。在整个植物生长阶段，将冬季小麦（Triticum aestivum cv. Xiaoyan22）种植在 ΣPAHs 污染的土壤上，保持 80%、60%或 40%的持水能力。分别在分蘖、抽穗或成熟阶段进行植物采样。本研究表明，随着土壤含水量的增加，作物的籽粒产量和生物量增加。在抽穗和灌浆期，80%和 60%持水能力处理下的小麦叶片蒸腾速率明显（p<0.05）高于 40%持水能力处理下的蒸腾速率。土壤含水量和植物生长阶段对冬季小麦中菲、蒽和芘的浓度有显著（p<0.0001）影响。当暴露于土壤中 0、15、60 和 150mgkg ΣPAHs 时，60%持水能力处理下的籽粒中 ΣPAHs 浓度分别为 80%持水能力处理下的 46.6%、69.9%、89.5%和 81.7%。作物中 ΣPAHs 的最高浓度出现在抽穗期。不同土壤水分处理和植物生长阶段，PAHs 在小麦不同组织中的分布不同。本研究表明，在冬季小麦生产过程中优化土壤水分含量可以明显降低籽粒中 ΣPAHs 的浓度，方法是影响 ΣPAHs 的根部吸收和 ΣPAHs 从茎或叶向籽粒的迁移，这表明水管理在应对 PAHs 污染方面具有潜力作物生长在 PAHs 污染的土壤上。
