Effects of manganese on the microstructures of Chenopodium ambrosioides L., A manganese tolerant plant

ABSTRACT

Chenopodium ambrosioides L. can tolerate high concentrations of manganese and has potential for its use in the revegetation of manganese mine tailings. Following a hydroponic investigation, transmission electron microscopy (TEM)-energy disperse spectroscopy (EDS) was used to study microstructure changes and the possible accumulation of Mn in leaf cells of C. ambrosioides in different Mn treatments (200, 1000, 10000 μmol·L⁻¹). At 200 μmol·L⁻¹, the ultrastructure of C. ambrosioides was clearly visible without any obvious damage. At 1000 μmol·L⁻¹, the root, stem and leaf cells remained intact, and the organelles were clearly visible without any obvious damage. However, when the Mn concentration exceeded 1000 μmol·L⁻¹ the number of mitochondria in root cells decreased and the chloroplasts in stem cells showed a decrease in grana lamellae and osmiophilic granules. Compared to controls, treatment with 1000 μmol·L⁻¹ or 10000 μmol·L⁻¹ Mn over 30 days, gave rise to black agglomerations in the cells. At 10000 μmol·L⁻¹, Mn was observed to form acicular structures in leaf cells and intercellular spaces, which may be a form of tolerance and accumulation of Mn in C. ambrosioides. This study has furthered the understanding of Mn tolerance mechanisms in plants, and is potential for the revegetation of Mn-polluted soils.

KEYWORDS:

• Chenopodium ambrosioides L.
• manganese
• tolerance
• ultrastructure

Acknowledgments

Financial support from National Natural Science Foundation of China (No. 40771181; No.31300815), Natural Science Foundation of Hunan Province, China (No. 2015JJ3142) is gratefully acknowledged. Chuan Wu acknowledges the Postdoctoral Science Foundation of Central South University in Changsha, P.R. China.