Abstract
Slight differences in the chemical behavior of germanium (Ge) and silicon (Si) during soil weathering enable Ge/Si ratios to be used as a tracer of Si pathways. Mineral weathering and biogenic silicon cycling are the primary modifiers of Ge/Si ratios, but knowledge of the biogenic cycling component is based on relatively few studies. We conducted two sets of greenhouse experiments in order to better quantify the range and variability in Ge discrimination by plants. Graminoid species commonly found in North American grassland systems, Agropyron smithii, Schizachyrium scoparium, and Andropogon gerardii were grown under controlled hydroponic environmental conditions. Silicon leaf contents were positively correlated with solution Si and ambient temperature but not with nutrient solution pH, electrical conductivity, or species. The Ge/Si ratio incorporated into phytoliths shows a distribution coefficient [(Ge/Si)phytolith/(Ge/Si)solution] of about 0.2 and is remarkably invariant between species, photosynthetic pathway, and solution temperature. Ge seems to be discriminated against during the uptake and translocation of Si to the opal deposition sites by about a factor of five. In the second experiment, a wider range of graminoid species (Agropyron smithii, Bouteloua gracilis, Buchloe dactyloides, Oryzopsis hymenoides, Schizachyrium scoparium and Andropogon gerardii) were grown in two different soil mediums. Plant phytoliths showed a distribution factor of about 0.4 for field grown grasses, and 0.6 for potting soil grown grasses with no clear trends among the species. Evidence of the direction and degree of biological Ge discrimination during plant uptake provides a geochemical finger print for plants and improves the utility of Ge/Si ratios in studies of terrestrial weathering and links between Si cycles in terrestrial and marine systems.
Similar content being viewed by others
References
Alexandre A, Meunier JD, Colin F, Koud JM (1997) Plant impact on the biogeochemical cycle of silicon and related weathering processes. Geochim Cosmochim Acta 61:677–682
Azam F, Volcani BE (1981) Germanium–silicon interactions in biological systems. In: Simpson TL, Volcani BE (eds) Silicon and siliceous structures in biological systems. Springer, New York, pp 43–67
Bareille G, Labracherie M, Mortlock RA, Maier-Reimer E, Froelich PN (1998) A test of (Ge/Si)opal as a paleorecorder of (Ge/Si)seawater. Geology 26:179–182
Blecker SW (2005) Silica biogeochemistry across the Great Plains. Dissertation, Colorado State University
Cakmak I, Kurz H, Marschner H (1995) Short-term effects of boron, germanium and high light-intensity on membrane-permeability in boron deficient leaves of sunflower. Physiologia Plantarum 95:11–18
Derry LA, Kurtz AC, Ziegler K, Chadwick OA (2005) Biological control of terrestrial silica cycling and export fluxes to watersheds. Nature 433:728–730
Epstein E (1994) The anomaly of silicon in plant biology. Proc Nat Acad Sci 91:11–17
Epstein E (1999) Silicon. Ann Rev Plant Physiol Plant Molec Bio 50:641–664
Epstein E (2001) Silicon in plants: Facts vs. concepts. In: Datnoff LE, Snyder GH, Korndorfer GH (eds) Silicon in agriculture. Elsevier, New York, pp 1–16
Filippelli GM, Carnahan JW, Derry LA, Kurtz A (2000) Terrestrial paleorecords of Ge/Si cycling derived from lake diatoms. Chem Geol 168:9–26
Froelich PN, Blanc V, Mortlock RA, Chillrud SN, Dunstan W, Udomkit A, Peng TH (1992) River fluxes of dissolved silica to the ocean were higher during glacials: Ge/Si in diatoms, rivers and oceans. Paleoceanography 7:739–767
Glockling F (1969) The chemistry of germanium. Academic Press, New York, pp 1–234
Halperin SJ, Barzilay A, Carson M, Roberts C, Lynch J (1995) Germanium accumulation and toxicity in barley. J Plant Nutr 18:1417–1426
Hodson MJ, White PJ, Mead A, Broadley MR (2005) Phylogenetic variation in the silicon composition of plants. Ann Bot 96:1027–1046
Ingli N (1963) Equilibrium studies of polyanions 12. Polygermanates in Na(Cl) medium. Acta Chemica Scan 17:597–616
Jarvis SC (1987) The uptake and transport of silicon by perennial ryegrass and wheat. Plant Soil 97:429–437
Jin K, Shibata Y, Morita M (1991) Determination of germanium species by hydride generation-inductively coupled plasma mass spectrometry Analyt Chem 63:986–989
Jones LHP, Handreck KA (1967) Silica in soils, plants and animals. Adv Agron 19:107–149
Kelly EF (1990) Methods for extracting opal phytoliths from soil and plant material. Colorado State University, Fort Collins, Colorado, pp 1–12
Kubicki JD, Heaney PJ (2003) Molecular orbital modeling of aqueous organosilicon complexes: implications for silica biomineralization. Geochim Cosmochim Acta 67:4113–4121
Kurtz AC, Derry LA, Chadwick OA (2002) Germanium-silicon discrimination in the weathering environment. Geochim Cosmochim Acta 66:1525–1537
Kurtz AC (2000) Germanium/Silicon and trace element geochemistry of silicate weathering and mineral aerosol deposition. Dissertation, Cornell University
Klaue B, Blum JD (1999) Trace analyses of arsenic in drinking water by inductively coupled plasma mass spectrometry: high resolution versus hydride generation Analyt Chem 71:1408–1414
Lajtha K, Jarrell WM, Johnson DW, Sollins P (1999) Collection of soil solution. In: Robertson GP, Coleman DC, Bledsoe C, Sollins P (eds) Standard soil methods for long-term ecological research. Oxford, New York, pp 166–182
Lewis BL, Andreae MO, Froelich PN (1989) Sources and sinks of methylgermanium in natural waters. Marine Chem 27:179–200
Lindsay WL (1979) Chemical equilibria in soils. John Wiley and Sons, New York, pp 51–56
Loomis WD, Durst RW (1992) Chemistry and biology of boron. Biofactors 3:229–239
Ma J F, Miyake Y, Takahashi E (2001) Silicon as a beneficial element for crop plants. In: Datnoff LE, Snyder GH, Korndorfer GH (eds) Silicon in agriculture. Elsevier, New York, pp 17–40
Ma J F, Nishimura K, Takahashi E (1989) Effect of silicon on the growth of rice plant at different growth stages. Soil Sci Plant Nutr 35:347–356
Ma JF, Tamai K, Yamaji N, Mitani N, Konishi S, Katsuhara M, Ishiguro M, Murata Y, Yano M (2006) A silicon transporter in rice. Nature 440:688–691
Marschner H (1995) Mineral nutrition in higher plants, 2nd ed. Academic Press, New York, pp 417–425
Mortlock RA, Froelich PN (1989) A simple method for the rapid determination of biogenic opal in pelagic marine sediments. Deep-Sea Res 36:1415–1426
Mortlock RA, Froelich PN (1996) Determination of germanium by isotope dilution-hydride generation inductively coupled plasma mass spectrometry. Analyt Chem Acta 332:277–284
Murnane RJ, Stallard RF (1990) Germanium and silicon in rivers of the Orinoco drainage basin. Nature 344:749–752
Parr JF, Lentfer CJ, Boyd WE (2001) A comparative analysis of wet and dry ashing techniques for the extraction of phytoliths from plant material. J Archaeolog Sci 28:875–886
Perry CC, Keeling-Tucker T (2000) Biosilicification: the role of the organic matrix in structure control. J Biol Inorg Chem 5:537–550
Piperno DR (1988) Phytolith analysis: an archaeological and geological perspective. Academic Press Inc., New York, pp 119–130
Pokrovski GS, Martin F, Hazemann JL, Schott J (2000) An X-ray absorption fine structure spectroscopy study of germanium-organic ligand complexes in aqueous solution. Chem Geol 163:151–165
Pokrovski GS, Schott J (1998) Experimental study of the complexation of silicon and germanium with aqueous organic species: implications for germanium and silicon transport and Ge/Si ratio in natural waters. Geochim Cosmochim Acta 62:3413–3428
Poulson SR, Drever JI, Stillings LL (1997) Aqueous Si-oxalate complexing, oxalate adsorption onto quartz, and the effect of oxalate upon quartz dissolution rates. Chem Geol 140:1–7
Prychid CJ, Rudall PJ, Gregory M (2003) Systematics and biology of silica bodies in monocotyledons. Botanical Rev 69:377–440
Rafi MM, Epstein E (1999) Silicon absorption by wheat (Triticum aestivum L.). Plant Soil 211:223–230
Rains DW, Epstein E, Zasoski RJ, Aslam M (2006) Active silicon uptake by wheat. Plant Soil 280:223–228
Raven JA (1983) The transport and function of silicon in plants. Biol Rev 58:179–207
Raven JA (2001) Silicon transport at the cell and tissue level. In: Datnoff LE, Snyder GH, Korndorfer GH (eds) Silicon in agriculture. Elsevier, New York, pp 41–55
Raven JA, Edwards D (2001) Roots: Evolutionary origins and biogeochemical significance. J Exp Bot 52:381–401
Sankhla N, Sankhla D (1967) Effect of germanium on growth of higher plants. Naturwissenschaften 54:621
Sangster AG, Hodson MJ (1992) Silica deposition in subterranean organs. In: Rapp Jr. G, Mulholland SC (eds) Phytolith systematics. Plenum Press, New York, pp 239–251
SAS Institute (2002) SAS/STAT user’s guide. Version 9.1. SAS Inst., Cary, NC
Takahashi E, Matsumoto H, Syo S, Miyake Y (1976) Variation in Ge uptake among plant species. Jpn J Soil Sci Plant Nutr 74:217–221
Van der Vorm PDJ (1980) Uptake of Si by five plant species, as influenced by variations in Si-supply. Plant Soil 56:153–156
Acknowledgements
This material is based upon work supported by the National Science Foundation under Grants No. DEB 0217631 and EAR 0208172 and funding from the Colorado Agricultural Experiment Station.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Blecker, S.W., King, S.L., Derry, L.A. et al. The ratio of germanium to silicon in plant phytoliths: quantification of biological discrimination under controlled experimental conditions. Biogeochemistry 86, 189–199 (2007). https://doi.org/10.1007/s10533-007-9154-7
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10533-007-9154-7