The enhancement by arbuscular mycorrhizal fungi of the Cd remediation ability and bioenergy quality-related factors of five switchgrass cultivars in Cd-contaminated soil

Abstract

A greenhouse experiment was carried out to investigate the effects of arbuscular mycorrhizal fungi (AMF) on the growth, P and Cd concentrations and bioenergy quality-related factors of five cultivars of switchgrass, including three lowland cultivars (Alamo (Ala), Kanlow (Kan), Performer (Per)) and two highland cultivars (Blackwell (Bw), Summer (Sum)), with 0, 1 and 10 mg/kg Cd addition levels. The results showed that AMF inoculation notably increased the biomass and P concentrations of all the cultivars. The Cd concentrations in the roots were higher than those in the shoots of all cultivars irrespective of inoculation, but the AMF had different effects on Cd accumulation in highland and lowland cultivars. AMF inoculation decreased the shoot and root concentrations in Ala and Kan, increased the shoot and root concentrations of Cd in Bw and Sum, and increased shoot Cd concentrations and decreased root Cd concentrations in Per. The highest Cd concentrations were detected in the roots of Bw and in the shoots of Sum with AMF symbiosis. Bw contained the highest total extracted Cd which was primarily in the roots. Ala had the second highest extracted Cd in the shoots, reaching 32% with 1 mg/kg of added Cd, whereas Sum had the lowest extracted Cd. AMF symbiosis had varied effects on bioenergy quality-related factors: for example, AMF decreased the ash lignin content in Ala and the C/N in Sum, increased the nitrogen, gross calorie values, and maintained the hemicellulose and cellulose contents in all cultivars with all tested concentrations of Cd. A principal component analysis (PCA) showed that AMF inoculation could enhance, weaken or transform (positive-negative, PC1-PC2) the correlations of these factors with the principle components under Cd stress. Therefore, AMF symbiosis enhanced the growth of different cultivars of switchgrass, increased/decreased Cd accumulation, promoted Cd extraction, and regulated the bioenergy quality-related factors in Cd-polluted areas. Bw is a suitable cultivar for phytostabilization due to high root Cd stabilization, whereas Ala is an appropriate cultivar for phytoremediation of less polluted areas because of its high Cd extraction and excellent bioenergy quality.

Potential phytoremediation of soil cadmium and zinc by diverse ornamental and energy grasses

“…There were eight switchgrass cultivars investigated in the present study (Table 1). Three cultivars, 'Alamo', 'Kanlow' and 'Blackwell', used herein, were also investigated by Sun et al (2018). Their ranking of Cd concentrations in shoot or root among the three cultivars differed from the present findings, but that of Cd accumulation in shoot and root were similar (Figs.…”

Comparative transcriptome analysis provides key insights into seedling development in switchgrass (Panicum virgatum L.)

“…Switchgrass can be used for livestock, water and soil conservation, and in the bioenergy sector, given the high water and fertilizer use efficiency of adult plants and its strong ability to adapt to adverse environmental conditions [47, 108]. Since slow and inconsistent seedling development affects large-scale plantations and reduces switchgrass utilization as a bioenergetic crop, the seedling development process was characterized in this study, and the transcriptomes of rapidly and slowly growing seedlings were compared to identify key genes involved in seedling development.…”

Phytomanagement of Metal(loid)-Contaminated Soils: Options, Efficiency and Value

“…Remarkable increases in P accumulation (82% in roots and 300% in shoots) were also observed in AMF- inoculated vetiver plants grown in a substrate containing coal mine wastes (Meyer et al, 2017). Plant growth promotion resulting from AMF inoculation has often been observed in energy crops growing in TE-contaminated soils (Merlos et al, 2016;Sun et al, 2018;He et al, 2020b, Table 6). Nonetheless, the effect of AMF inoculation on TE accumulation in plant tissues is highly variable (Wong et al, 2007;Guo et al, 2013;Meyer et al, 2017;Sun et al, 2018).…”

“…Plant growth promotion resulting from AMF inoculation has often been observed in energy crops growing in TE-contaminated soils (Merlos et al, 2016;Sun et al, 2018;He et al, 2020b, Table 6). Nonetheless, the effect of AMF inoculation on TE accumulation in plant tissues is highly variable (Wong et al, 2007;Guo et al, 2013;Meyer et al, 2017;Sun et al, 2018). For instance, the accumulation of TE in roots and shoots of vetiver plants varied according to the AMF species used for bioaugmentation (actually, some species increased TE accumulation while others decreased it) (Meyer et al, 2017).…”