Environmental and Food Laboratories (LIAA), Department of Medical Science, Surgical and Advanced Technologies "G.F. Ingrassia", University of Catania, Italy.
Environmental and Food Laboratories (LIAA), Department of Medical Science, Surgical and Advanced Technologies "G.F. Ingrassia", University of Catania, Italy.
Environ Res. 2020 Jun;185:109427. doi: 10.1016/j.envres.2020.109427. Epub 2020 Mar 22.
Soil pollution from heavy metals poses a serious risk for environment and public health. Phytoremediation is an eco-friendly and cheaper alternative compared to chemical-physical techniques. We carried out in vitro tests where three microorganisms Trichoderma harzianum, Saccharomyces cerevisiae and Wickerhamomyces anomalus were exposed to eight different heavy metals (one metal at a time) in order to evaluate resistance, growth and bioaccumulation capability for each metal (Ni, Cd, Cu, V, Zn, As, Pb, Hg). Taking into account the natural characteristics of T. harzianum, (resistance to environmental stress, resistance to pathogenic fungi, ability to establish symbiotic relationships with superior green plants) and the good bioaccumulation capacity for V, As, Cd, Hg, Pb shown after in vitro tests, it was chosen as a microorganism to be used in greenhouse tests. Controlled exposure tests were performed in greenhouse, where Arundo donax and mycorrhized Arundo donax with T. harzianum were exposed for 7 months at two different doses (L1 and L2) of a heavy metal mix, so as to assess whether the symbiotic association could improve the bioaccumulation capability of the superior green plant A. donax. Heavy metals were determined with ICP-MS. The average bioaccumulation percentage values of A. donax for L1 and L2 were, respectively: Ni (31%, 26%); Cd (35%, 50%); Cu (30%, 35%); As (19%, 27%); Pb (18%, 14%); Hg (42%, 45%); V (39%, 26%); Zn (23%, 9%). The average bioaccumulation percentage values of mycorrhized A. donax with T. harzianum for L1 and L2 were, respectively: Ni (27%, 38%); Cd (44%, 42%); Cu (36%, 29%); As (17%, 23%); Pb (37%, 54%); Hg (44%, 60%); V (16%, 20%); Zn (14%, 7%). A. donax showed the highest BAF (bioaccumulation factor) for Cd (0.50), Cu (0.35), As (0.27) and Hg (0.45) after exposure to L2; mycorrhized A. donax with T. harzianum showed the highest BAF for Ni (0.38), Cd (0.42), Pb (0.54) and Hg (0.60) after exposure to L2. A. donax showed the highest TF (translocation factor) values for Cd (0.28) and Hg (0.26) after exposition at L1 and L2 respectively; A. donax mycorrhized with T. harzianum showed the highest TF values for Cd (0.70), As (0.56), V (0.24), Pb (0.18) after exposition at L2, and Zn (0.30) after exposition at L1. Our study showed a good growth capability in contaminated soils and a good bioaccumulation capability of heavy metals, both for A. donax and mycorrhized A. donax with T. harzianum. Furthermore, for three metals (Ni, Pb and Hg) the bioaccumulation capability was improved by the symbiosis of T. harzianum with A. donax. So, these results proved the suitability both for A. donax and mycorrhized A. donax with T. harzianum for phytoremediation processes.
重金属土壤污染对环境和公共健康构成严重威胁。与化学-物理技术相比，植物修复是一种更环保、更经济的替代方法。我们进行了体外试验，将三种微生物哈茨木霉、酿酒酵母和异常威克汉姆酵母暴露于八种不同的重金属（一次一种金属）中，以评估每种金属（镍、镉、铜、钒、锌、砷、铅、汞）的抗性、生长和生物累积能力。考虑到哈茨木霉的自然特性（对环境胁迫的抗性、对致病真菌的抗性、与优质绿色植物建立共生关系的能力）以及体外试验后显示出的对 V、As、Cd、Hg、Pb 的良好生物累积能力，选择其作为一种微生物在温室试验中使用。在温室中进行了对照暴露试验，在两个不同剂量（L1 和 L2）的重金属混合物中，将芦竹和丛枝菌根芦竹暴露 7 个月，以评估共生关系是否能提高优质绿色植物芦竹的生物累积能力。用 ICP-MS 测定重金属。L1 和 L2 下芦竹的平均生物累积百分比值分别为：镍（31%，26%）；镉（35%，50%）；铜（30%，35%）；砷（19%，27%）；铅（18%，14%）；汞（42%，45%）；钒（39%，26%）；锌（23%，9%）。T. harzianum 丛枝菌根芦竹的平均生物累积百分比值分别为：镍（27%，38%）；镉（44%，42%）；铜（36%，29%）；砷（17%，23%）；铅（37%，54%）；汞（44%，60%）；钒（16%，20%）；锌（14%，7%）。芦竹在 L2 暴露后对 Cd（0.50）、Cu（0.35）、As（0.27）和 Hg（0.45）的 BAF（生物累积因子）最高；T. harzianum 丛枝菌根芦竹在 L2 暴露后对 Ni（0.38）、Cd（0.42）、Pb（0.54）和 Hg（0.60）的 BAF 最高。芦竹在 L1 和 L2 暴露后对 Cd（0.28）和 Hg（0.26）的 TF（转移因子）值最高；T. harzianum 丛枝菌根芦竹在 L2 暴露后对 Cd（0.70）、As（0.56）、V（0.24）、Pb（0.18）和 Zn（0.30）的 TF 值最高。我们的研究表明，芦竹和丛枝菌根芦竹在污染土壤中有良好的生长能力和重金属的良好生物累积能力。此外，对于三种金属（镍、铅和汞），哈茨木霉与芦竹的共生提高了它们的生物累积能力。因此，这些结果证明了芦竹和丛枝菌根芦竹用于植物修复过程的适宜性。
