Department of Plant Biology and Ecology, University of the Basque Country/EHU, P.O. Box 644, E-48080 Bilbao, Spain.
Sci Total Environ. 2011 Sep 1;409(19):4087-93. doi: 10.1016/j.scitotenv.2011.06.025. Epub 2011 Jul 7.
Soil contamination due to petroleum-derived products is an important environmental problem. We assessed the impacts of diesel oil on plants (Trifolium repens and Lolium perenne) and soil microbial community characteristics within the context of the rhizoremediation of contaminated soils. For this purpose, a diesel fuel spill on a grassland soil was simulated under pot conditions at a dose of 12,000 mg diesel kg(-1) DW soil. Thirty days after diesel addition, T. repens (white clover) and L. perenne (perennial ryegrass) were sown in the pots and grown under greenhouse conditions (temperature 25/18 °C day/night, relative humidity 60/80% day/night and a photosynthetic photon flux density of 400 μmol photon m(-2) s(-1)) for 5 months. A parallel set of unplanted pots was also included. Concentrations of n-alkanes in soil were determined as an indicator of diesel degradation. Seedling germination, plant growth, maximal photochemical efficiency of photosystem II (F(v)/F(m)), pigment composition and lipophylic antioxidant content were determined to assess the impacts of diesel on the studied plants. Soil microbial community characteristics, such as enzyme and community-level physiological profiles, were also determined and used to calculate the soil quality index (SQI). The presence of plants had a stimulatory effect on soil microbial activity. L. perenne was far more tolerant to diesel contamination than T. repens. Diesel contamination affected soil microbial characteristics, although its impact was less pronounced in the rhizosphere of L. perenne. Rhizoremediation with T. repens and L. perenne resulted in a similar reduction of total n-alkanes concentration. However, values of the soil microbial parameters and the SQI showed that the more tolerant species (L. perenne) was able to better maintain its rhizosphere characteristics when growing in diesel-contaminated soil, suggesting a better soil health. We concluded that plant tolerance is of crucial importance for the recovery of soil health during rhizoremediation of contaminated soils.
由于石油衍生产品造成的土壤污染是一个重要的环境问题。我们评估了柴油对植物（三叶草和黑麦草）和受污染土壤中土壤微生物群落特征的影响，以此作为受污染土壤的根际修复的一部分。为此，在盆栽条件下，以 12000mg 柴油 kg(-1)DW 土壤的剂量模拟了草原土壤上的柴油燃料溢油。柴油添加 30 天后，在温室条件下（温度 25/18°C 昼夜，相对湿度 60/80%昼夜和 400 μmol 光子 m(-2) s(-1)的光合光通量密度）在盆中播种并种植 T. repens（白三叶草）和 L. perenne（多年生黑麦草），持续 5 个月。还包括一组平行的未种植的盆。土壤中直链烷烃的浓度被确定为柴油降解的指标。种子发芽率、植物生长、最大光化学效率（F(v)/F(m)）、色素组成和脂溶性抗氧化剂含量被用来评估柴油对研究植物的影响。还测定了土壤微生物群落特征，如酶和群落水平生理特征，并用来计算土壤质量指数（SQI）。植物的存在对土壤微生物活性有刺激作用。与 T. repens 相比，L. perenne 对柴油污染的耐受性要强得多。柴油污染影响了土壤微生物特性，尽管其对 L. perenne 根际的影响不太明显。T. repens 和 L. perenne 的根际修复导致总直链烷烃浓度的相似降低。然而，土壤微生物参数和 SQI 值表明，在生长在受柴油污染的土壤中时，更耐受的物种（L. perenne）能够更好地保持其根际特征，表明土壤健康状况更好。我们得出结论，植物的耐受性对于受污染土壤的根际修复过程中土壤健康的恢复至关重要。
