Effect of mycorrhizal inoculations on heavy metal uptake and stress alleviation of Cajanus cajan (L.) Millsp. genotypes grown in cadmium and lead contaminated soils

Abstract

The aim of the present study was to evaluate the role of arbuscular mycorrhizal (AM) fungi on metal uptake, oxidative effects and antioxidant defence mechanisms under cadmium (Cd) and lead (Pb) stresses in Cajanus cajan (L.) Millsp. (pigeonpea). Treatments consisted of two concentrations each of Cd (25 and 50 mg/kg of soil) and Pb (500 and 800 mg/kg of soil) singly as well as in combination. Both metals induced oxidative damage through increased lipid peroxidation, electrolyte leakage and hydrogen peroxide levels, but Cd was found to be more toxic than Pb. Compared with the effects of Cd or Pb alone, the combination of Cd and Pb acted synergistically; however, Pb immobilisation in soil controlled the uptake of Cd in plants. There was a direct correlation between the type of genotype, heavy metal content and oxidative damage in concentration dependent manner. Superoxide dismutase (SOD), catalase (CAT) and peroxidase (POX) increased under stress. The toxicity symptoms of the metal stress were significantly higher in Sel-141-97 genotype when compared with Sel-85 N. The high ratio of glutathione to its oxidised form, glutathione disulfide (GSH/GSSG), could be restored by means of higher glutathione reductase (GR) activity and increased GSH synthesis in mycorrhizal stressed plants. AM inoculations with Glomus mosseae significantly arrested uptake of Cd and Pb into the root system and further translocation into the above ground parts and led to decreased lipid peroxidation and electrolyte leakage. Increased activities of SOD, CAT, POX as well as GR were observed in all mycorrhizal stressed plants.

Effect of mycorrhizal inoculation on metal accumulation by poplar leaves at phytomanaged sites

“…It is interesting to note that the filter function of arbuscular mycorrhizal fungi (AMF), in the case of highly contaminated soils, dominates the literature, as for example in the works described by Meier et al (2012b) and Garg and Aggarwal (2012), most of the studies being performed in pot experiments. Conversely, some authors demonstrated that the inoculation of plants by AMF such as Glomus species significantly enhanced PTE translocation to the aboveground parts of plants (Meier et al, 2012a).…”

Essential oil content and chemical composition of Cymbopogon citratus inoculated with arbuscular mycorrhizal fungi under different levels of lead

“…Wei and Wang (1991) reported that Schizonepeta tenuifolia increased EO production, plant biomass and nutrient uptake significantly when these plants were inoculated with AMF. Garg and Aggarwal (2012) and Lermen et al (2015) observed that AMF are potentially able to minimize plant uptake of HMs such as Pb. However, this evidence is not the general rule because some plants do not respond to the AMF association.…”

Metal uptake, oxidative metabolism, and mycorrhization in pigeonpeaand pea under arsenic and cadmium stress

“…Exposure to Cd drives oxidative injuries, such as lipid peroxidation, which leads to alteration in the membrane functionality and protein carbonylation (Schützendübel et al, 2001;Romero-Puertas et al, 2002;DalCorso et al, 2008DalCorso et al, , 2010Garg and Aggarwal, 2012). A possible constitutive mechanism of detoxification in plants is upregulation of antioxidants such as superoxide dismutase (SOD), ascorbate peroxidase (APX), glutathione reductase (GR), peroxidase (POX), and catalase (CAT) (Meharg, 2005;Gomes et al, 2012;Dave et al, 2013;Sobrino-Plata et al, 2014).…”