Chemical- and microbial-enhanced phytoremediation of cadmium-contaminated calcareous soil by maize

Abstract

Phytoremediation is an appropriate technology used to remove pollutants from environment components. A greenhouse trial was conducted to test the hypothesis that application of surfactant levels and inoculation with Pseudomonas fluorescens bacterium and/or Piriformospora indica fungus enhances the phytoremediation of cadmium (Cd). Maize seeds were sown in Cd-polluted soil, and after 2 months Cd status in plant tissues and Cd phytoremediation criteria was determined. Results showed that application of surfactant increased root and shoot dry weight. Mean Cd uptake in roots and shoots increased following the application of 2 and 4 mmol kg À1 Tween 80, respectively. Application of 2 mmol kg À1 Tween 80 increased mean Cd uptake efficiency, while application of 4 mmol kg À1 Tween 80 increased phytoextraction and translocation efficiencies. Inoculation with P. indica and P. fluorescens was mostly effective in increasing Cd uptake and Cd phytoextraction efficiency, respectively. Co-inoculation with P. indica and P. fluorescens had no superiority to application of each inoculant alone. Since most of the Cd remained in roots, phytostabilization is probably the main mechanism controlling Cd phytoremediation by maize. According to the results, application of Tween 80 and inoculation with P. indica and P. fluorescens effectively enhanced phytoremediation of Cd-contaminated soil by maize.

Impacts of the Inoculation of Piriformospora indica on Photosynthesis, Osmoregulatory Substances, and Antioxidant Enzymes of Alfalfa Seedlings under Cadmium Stress

“…In functional and growth-promotion aspects, P. indica can promote plant growth [30], and the absorption and utilization of nutrients, while improving the plants' nutritional value [28]. This effect has been seen in corn [27] and wheat [31]. Inoculation of P. indica increased chlorophyll content and tolerance of alfalfa in the Phenanthrene and Cadmium co-contaminated soil [16].…”

“…It can also enhance the expression of antioxidant system components and stress-related genes [20][21][22] and induce plant stress resistance [23][24][25]. P. indica has been reported to enhance the activity of antioxidant enzyme systems in barley [26], corn [27], and banyan [28]. In addition, under both mycorrhizal association and stresses, the content of proline involved in the resistance to oxidative stress of cells also increased [29].…”

Transcriptomic and physiological analyses of Trichoderma citrinoviride HT-1 assisted phytoremediation of Cd contaminated water by Phragmites australis

“…Wang et al resulted that PGPM inoculants enhanced oilseed Cd concentration and Cd phytoextraction efficiency, and the soil Cd removal rate of PGPM inoculated plants was 2.44 times higher than that of non-inoculated plants [ 54 ]. Asilian et al inoculated Piriformospora indica increased plant root Cd concentration and the uptake of maize [ 55 ]. Chen et al reported that inoculating Sphingomonas SaMR12 significantly increased Zn uptake by S. alfredii was close to 23 fold [ 56 ].…”

Root fungal endophytes: identity, phylogeny and roles in plant tolerance to metal stress

“…Furthermore, the same fungal species showed antagonistic effects on different plants, decreasing or increasing metal accumulation. This is the case for Piriformospora indica, which increases wheat but decreases maize metal uptake (Asilian et al, 2019;Shahabivand et al, 2012), or Trichoderma asperellum, which has no effect on Lactuca serriola metal uptake and translocation but shows a negative effect on onion and Suaeda salsa metal uptake and translocation (Li et al, 2019;Téllez-Vargas et al, 2017;Ważny 2018). It has been shown for AMF that fungal tolerance may vary individually, with local adaptation to metal contamination at the intraspecific level (Colpaert et al, 2004;Jourand et al, 2010;Vallino et al, 2011).…”