Fig 1.
(A) Colony of gametophytes bearing bright yellowish mature sporophytes. (B) Spore germination at 48 hours after sowing. Scale bar = 20 μm. (C) Suspension culture in a 0.5 L bottle. (D) SEM photograph of a freeze-dried cell pellet. Bright spots in the inset represent chloroplasts. Scale bar = 250 μm. A magnified view of the cells is shown in the inset. Scale bar = 10 μm.
Table 1.
Maximum adsorption capacity for 15 elements in the moss Funaria hygrometrica.
Fig 2.
TEM-EDX analysis of F. hygrometrica protonemal cells.
(A) Control cell. (B to E) Cells treated with 0.1 mM PbCl2. The thickness of (A) and (B) is 80 nm, and that of (C) to (E) is 150 nm. (C), (D), and (E) are views focusing on the cell wall, endoplasmic reticulum (plasmodesmata), and chloroplast, respectively. Arrows indicate the X-ray analytical areas. Magnified views of the analyzed areas are shown in the inset. cw, cell wall, ch, chloroplast, er, endoplasmic reticulum, mt, mitochondrion. Scale bars: 1 μm. (F, G, H) Energy-disperse spectroscopic spectra. (F), (G), and (H) show results of the analyses of (C), (D), and (E), respectively. Peaks marked by closed arrowheads were used for Pb identification: 2.35(Mα), 10.55(Lα1) and 10.45(Lα2), and 12.61(Lβ1) and 12.62(Lβ2) keV. Peaks highlighted by open arrowheads originated from the Cu in the sample-holding grid (8.05(Kα1) and 8.91(Kβ) keV).
Fig 3.
Adsorption of Pb to prepared a cell-wall fraction of F. hygrometrica.
Aliquots of a cell-wall (CW) fraction were suspended in MQW (Mock), 1 mM PbCl2, or 1 mM Pb(NO3)2. After washing with MQW, Pb was detected with rhodizonic acid staining and X-ray analysis. (A) Precipitated CW fractions in bottles after treatment. (B) Autiofluorescence image of rhodizonic acid-stained CW fraction observed with Bio Imaging Navigator with a fluorescence filter (FSX100/U-MNUA2, OLYMPUS, Japan). (C) Observation with bright field mode. (D) Spectra of X-ray analysis with an X-ray analyzer. Background peaks in mock treatment are derived from rhodizonic acid. Scale bars, 3 mm in (A), 100 μm in (B) and (C).
Fig 4.
NMR analysis of cell-wall fraction of moss, F. hygrometrica.
(A) 1H-13C HSQC analysis. Expanded polysaccharide regions of 1H-13C HSQC spectra from individually characterized commercial reagents, cellooligosaccharides (red) and PGA(yellow), were overlaid on the spectra obtained from the cell-wall fraction of F. hygrometrica (black), Physcomitrella patens (blue), and Ceratodon purpureus (yellow-green) (B) Comparison of cell-wall fractions based on hierarchial component analysis of 1H-13C HSQC spectra. Comparison of cell-wall fraction prepared from land plants, aquatic plants (seeweeds), and F. hygrometrica based on HCA of their 1H-13C HSQC spectra. Trees: T1, Castanopsis sieboldii; T2, Crypromeria japonica; T3, Populus. Grasses: G1, Erianthus; G2, Pennisetum americanum; G3, Panicum maximum Jacq.; G4, Brachypodium; G5, Oryza sativa; G6, Triticum aestivum; G7, Arabidopsis thaliana. Brown algae: BA1, Ishige okamurae; BA2, Sargassum micracanthum; BA3, Sargassum ringgoldianum; BA4, Sargassum hemiphyllum; BA5, Sargassum patens. Green algae: GA1, Ulva pertusa; GA2, Codium subtubulosum; GA3, Codium fragile. Red algae: RA1, Gelidium elegans; RA2, Ahnfeltiopsis flabelliformis; RA3, Prionitis divaricata. Bryophytes: PP, Physcomitrella patens; CP, Ceratodon purpureus; FH, Funaria hygrometrica.
Fig 5.
Effect of Pb on moss growth in culture.
(A) Growth of F. hygrometrica on modified Knop’s-agar medium containing 0.5 mM PbCl2. At each time point, the dry weight was measured. (B) Effect of PbCl2 on the growth yield of F. hygrometrica and P. patens at 10 days after sowing. Protonemal cells of F. hygrometrica and P. patens were grown on modified Knop’s-agar medium containing various concentrations of PbCl2. Index of growth yield [%] = (B/A) × 100, where A is the average weight of the control, and B is the weight of the PbCl2-treated sample. Error bars represent the standard deviation of three biological replicates. Measurements marked with asterisks differ significantly as assessed by Welch’s t-test at p <0.05.
Fig 6.
Effects of pH on metal adsorption.
F. hygrometrica protonemal cells were incubated with the metal solutions at the indicated pH values, and the unbound metals in the filtrates were quantified. Adsorption rate (%) = (initial concentration − final concentration) / initial concentration × 100.