Table 1.
Manganese content in the soils, leaves and stems of the plant species from the Mn site at the Liangcheng mining area in southeastern China.
Fig 1.
Eucalyptus grandis × E. urophylla growing at Liancheng manganese tailings in Southern China.
Fig 2.
Observed Mn toxicity in Eucalyptus grandis × E. urophylla.
Seedlings were treated in hydroponic solution with different levels of Mn for one week. A, the control Hoagland solution plus (5 μM); B, 500 μM; C, 5×103 μM; D, 10×103 μM; E, 20×103 μM Mn. The white arrow in D indicated young leaves which turned purple, curled and crinkling symptoms under 10×103 μM Mn treatment.
Fig 3.
Accumulation of Mn in the roots, stems and leaves of Eucalyptus grandis × E. urophylla.
Seedlings were treated with different Mn treatments (5, 500, 104 and 2×104 μM) in hydroponic solution for one week. Mn content in different tissues was measured with ICP-OES. Data represents mean ± SE. (n = 3).
Fig 4.
Anatomical structure of the Eucalyptus grandis × E. urophylla:
a leaf from the mining area (A) including the upper epidermis (1), palisade (2), sponge tissue (3), lower epidermis (4), xylem of vein (5), phloem of vein (6) and collenchyma (7); stem from mining area (B) including the periderm (8), phloem (9), cambium (10), xylem near the cambium (11), xylem near the vessel (12), vessel (13). (C) Distribution of Mn in the leaf cross-section. (D) Distribution of Mn in the stem cross-section. The empty bar represented samples from the control area (CA) and the filled gray bar represented samples from the mine tailing area (Mine). Data represents mean ± SE. (n = 3). (The asterisks on the bars indicate significant differences after t-test statistical analyses, *p < 0.05).
Fig 5.
Subcellular distribution of Mn.
CA represents samples from the control area, and Mine represents samples from the mine tailing area. Data represents mean ± SE. (n = 3).
Fig 6.
SEC/UV/ICPMS chromatograms of the water-soluble fractions from leaves and stems of Eucalyptus grandis × E. urophylla.
The leaves (A) and stems (C) from the control area; the leaves (B) and stems (D) from the mining area; Peak 1, Mn associated with high molecular weight proteins; peak 2, Mn associated with low molecular weight compounds.
Fig 7.
Elution profiles of leaf subcellular soluble proteins with Size-exclusion columns coupled to ICP-MS.
(Leaf samples all from the mining area.) Covalently-bound cell wall protein (A) and ionically-bound cell wall protein (B); Chloroplast PSI(C); Chloroplast PSII (D) and Vacuole protein (E). 1, high molecular weight chelate; 2, middle molecular weight chelate; 3, low molecular weight.
Fig 8.
Concentrations of organic acids in leaves (A) and stems (B).
The empty bar represents samples from the control area (CA) and the filled gray bar represents samples from the Mn site of the mine tailing area. Data represents mean ± SE. (n = 3). The asterisks on the bars indicate significant differences after t-test statistical analyses, *p < 0.05.
Fig 9.
Typical chromatogram of ten organic acid standards by RP-HPLC
(A). a, oxalic acid; b, tartaric acid; c, formic acid; d, malic acid; e, lactic acid; f, acetic acid; g, maleic acid; h, citric acid; i, fumaric acid; j, succinic acid. (B) RP-HPLC of the small molecular-Mn complexes in the leaf sample peak 2 (Fig 6B).