Sarehi Ebrahimi, Seyed Mehdi Razavi, Mansour Afshar Mohammmadian,
Volume 10, Issue 1 (6-2023)
Abstract
The increase of the entry of industrial effluents containing various types of heavy metals into water and soil leads to the ever-increasing spread of environmental problems. Therefore, it is necessary to find less expensive solutions to reduce the pollution. In this regard, in order to compare the effect of the removal of heavy elements on some of the morphological and physiological characteristics of C. alternifolius, Ch. zizanioides and Aloe vera plants, an experiment was conducted in the form of a randomized complete block design with three replications for 14 months at the University of Guilan. The results showed that under the treatment of industrial wastewater, the metal accumulation indices (MAI) of zinc, chromium, lead, copper, manganese, nickel, magnesium were higher in Ch. zizanioides and Aloe vera than those in C. alternifolius. In all three studied plants, the indices of root length, shoot length, total biomass and tolerance index (TI) had a significant decrease compared with those in the control plants, and Ch. zizanioides and A. vera plants had the lowest percentage of decrease. In addition, other investigated components including absorption index (UI), total soluble sugar, total phenol content, total flavonoid, total anthocyanin, total tannin, and DPPH free radical inhibition percentage increased in all three plants under industrial wastewater treatment. The highest percentage of increase in all investigated components, except DPPH free radical inhibition percentage, was observed in Ch. zizanioides. In general, it can be said that in terms of MAI and morphological and physiological characteristics, Ch. zizanioides and A. vera were more successful than the C. alternifolius. Therefore, it is recommended to plant the studied plants in the order of priority (Ch. zizanioides ˃ A. vera ˃ C. alternifolius) in soils contaminated with industrial effluents, in order to remediate the soil.
Fereshteh Mohamadhasani Javar, Mehdi Rahimi,
Volume 10, Issue 2 (9-2023)
Abstract
Heavy metal contamination (HMs) of water and soil is the most serious problem caused by industrial and mining processes and other human activities. Mycoremediation is a biotechnological method that employs fungi to remove toxic contaminants from the environment in an efficient and cost-effective manner. Pleurotus species are considered to be the most popular and widely cultivated species worldwide, and this may be due to their low production cost and high yield. It has been indicated that Pleurotus species may improve plant growth in metal-contaminated soils through enhancing nutrition uptake or by alleviating toxicity of the metals. In this experiment, the fungus was grown in vitro in liquid and solid media for 3 weeks on five different concentrations (0, 15, 30, 45, 60 ppm) of five heavy metals (Cd, Zn, Ni, Pb, Mn) as sulphate and the effect of these metal on radial growth, biomass production and metal content of fungal biomass were determined. Based on the results, this fungus showed a great variety of tolerance against the metals, as that growth parameters were increased in the case of two metals contamination (Zn and Mn) and inhibition of growth was observed even at the low concentrations of nickel, cadmium and lead (15 mg/liter). The amount of metal accumulation in the fungal mycelium also increased with the increase of the metal concentration in the culture medium. In this research, for the first time, the growth parameters and the amount of accumulation of heavy metals in axenic conditions have been investigated and described.
