Department of Botany, Faculty of Science, University of Ruhuna, Matara, Sri Lanka.
School of Biological and Marine Sciences, University of Plymouth, Drake Circus, Plymouth, United Kingdom.
Ecotoxicol Environ Saf. 2020 Jan 30;188:109911. doi: 10.1016/j.ecoenv.2019.109911. Epub 2019 Nov 11.
Screening of plant species with an ability to grow on contaminated soil is the most critical step in the planning of a phytoremediation program. While flourishing growth of Impatiens balsamina L. and Crotalaria retusa L. has been observed in areas adjacent to automobile service stations in Sri Lanka, no systematic study of their tolerance to used lubricating oil (ULO) contaminated soil has been carried out. Therefore, the aim of the present study was to investigate the comparative responses of I. balsamina L. and C. retusa L. to soil contaminated with ULO. Both species exhibited 100% seed germination in soils treated with 1%-5% w/w ULO. After 120 h exposure, root lengths and biomass of germinated seedlings of both species were significantly (p < 0.05) reduced in all treatments above 3% w/w ULO. The measured growth parameters of plants following 90 d exposure to 0.5-3% w/w ULO, indicated significant (p < 0.05) negative effects on I. balsamina and C. retusa at >1% w/w and >2% w/w ULO, respectively. There were no significant effects on chlorophyll content or root anatomy of either species under any treatments. Therefore, we concluded that I. balsamina can tolerate up to 1% of ULO and C. retusa up to 2% w/w ULO without displaying any negative effects. Comparatively higher biodegradation of ULO in the rhizosphere, root nodule formation, increases in root length and root hair density are all possible strategies for the exhibited higher tolerance of C. retusa. Therefore, the overall results indicate that C. retusa has the greater potential to be used in phytoremediation of ULO contaminated soils. The findings of the present study will be beneficial in planning phytoremediation program for ULO contaminated soil.
筛选具有在污染土壤上生长能力的植物物种是植物修复计划规划中最关键的步骤。虽然在斯里兰卡紧邻汽车服务站的区域观察到凤仙花和猪屎豆的旺盛生长，但尚未对它们对使用过的润滑油（ULO）污染土壤的耐受性进行系统研究。因此，本研究的目的是调查凤仙花和猪屎豆对受 ULO 污染土壤的比较反应。两种物种在 1%-5%w/w ULO 处理的土壤中均表现出 100%的种子发芽率。暴露 120 小时后，两种物种的发芽幼苗的根长和生物量在所有处理中均显著（p<0.05）低于 3%w/w ULO 以上。暴露 90 天后，用 0.5-3%w/w ULO 处理植物的测量生长参数表明，对凤仙花和猪屎豆分别在>1%w/w 和>2%w/w ULO 下有显著（p<0.05）的负面影响。在任何处理下，两种物种的叶绿素含量或根解剖结构均无显著影响。因此，我们得出结论，凤仙花可耐受高达 1%的 ULO，猪屎豆可耐受高达 2%w/w ULO，而不会产生任何负面影响。在根际中对 ULO 进行比较高的生物降解、根瘤形成、根长增加和根毛密度增加，这些都是猪屎豆表现出更高耐受性的可能策略。因此，总体结果表明，猪屎豆在修复受 ULO 污染土壤方面具有更大的潜力。本研究的结果将有助于规划受 ULO 污染土壤的植物修复计划。
