Field Evaluation of Arbuscular Mycorrhizal Fungal Colonization in Miscanthus × giganteus and Seed-Based Miscanthus Hybrids Grown in Heavy-Metal-Polluted Areas

Abstract

Understanding the behavior of arbuscular mycorrhizal fungi (AMF) associated with plants is essential for optimizing plant cultivation to the phytoremediation of degraded soils. The objective of the present study was to evaluate the differences in AMF root colonization between novel seed-based interspecific Miscanthus hybrids (M. sacchariflorus × M. sinensis) and the standard M. × giganteus when grown in soils contaminated with heavy metals (Pb, Cd, and Zn). During the third and fourth growing seasons, higher levels of metals in the roots and a reduced transfer of metals from the roots to the shoots were observed in all the plants studied. After the third growing season, GNT5 had the highest AMF root colonization rates in soil contaminated with heavy metals. The lowest AMF colonization rates were observed for the GNT34 hybrid. After the fourth growing season, AMF colonization decreased, which could be due to the drought that occurred during that season. GNT34 showed a lower tendency to develop mycorrhizal structures on heavy-metal (HM)-contaminated soils than GNT41 and M × g; however, this cultivar was insensitive to changes in colonization rates during the dry growing season.

Season-dependent physiological behavior of Miscanthus x giganteus growing on heavy-metal contaminated areas in relation to soil properties

“…It is frequently reported that Miscanthus x giganteus behaves as an excluder sequestering most absorbed heavy metals in the root system [ 11 , 12 , 14 , 18 , 41 ]. The present work, however, showed that heavy metals may also accumulate to some extent in the shoot part (mainly Cd, Zn, Ni and to a lower extent Cu) and may uptake As, supporting the view of Kocón and Matyka [ 43 ] and Barbosa et al [ 10 ] who showed that Miscanthus x giganteus may be used for Cd and Zn phytoextraction purposes.…”

“…According to Nsanganwimana et al [ 11 ], Cd, Pb and Zn accumulations in roots may reach up to 120, 105 and 280 mg Kg −1 DW, respectively, while the highest values recorded in leaves were 3, 15 and 80 mg Kg −1 DW for Cd, Pb and Zn, respectively. Hence, the majority of absorbed heavy metals remain in the roots [ [12] , [13] , [14] ] but a consistent part of those pollutant may be translocated to the shoot [ 15 , 16 ]. The proportion of metals reaching aerial parts may vary according to the considered element, the phenological stage of the plant and agronomical practices [ 17 ].…”

The effect of combined drought and trace metal elements stress on the physiological response of three Miscanthus hybrids

“…Published data mostly refer to a combination of heat and drought stress 14 – 16 . There is limited work on the effects of drought and trace metal elements (TME) 2 , 17 , 18 , especially for energy crop species 6 , 19 , 20 that could be grown on TME-contaminated soils without risk to humans. Rusinowski et al 21 showed that the influence of TME-contaminated soils on the photosynthetic apparatus of three C4 grasses ( Miscanthus × giganteus , Panicum virgatum and Spartina pectinata ) was low when measured in field-cultivated mature plantations.…”