Influence of Vetiver Grass (Vetiveria zizanioides) on Rhizosphere Chemistry in Long-term Contaminated Soils

중금속으로 오염된 토양에서 근권부의 화학적 특성에 미치는 vetiver grass (Vetiveria zizianioides)의 영향

  • Kim, Kwon-Rae (Centre for Environmental Risk Assessment and Remediation, University of South Australia) ;
  • Owens, Gary (Centre for Environmental Risk Assessment and Remediation, University of South Australia) ;
  • Naidu, Ravi (Centre for Environmental Risk Assessment and Remediation, University of South Australia) ;
  • Kim, Kye-Hoon (Department of Environmental Horticulture, University of Seoul)
  • Received : 2008.01.04
  • Accepted : 2008.02.10
  • Published : 2008.02.28

Abstract

A detailed understanding and appreciation of the important mechanisms operating at the soil:root interface, commonly identified as the rhizosphere, is critical for evaluating the potential for particular plant species to be successfully used as part of a phytoremediation technique. For specific plants, mechanisms may exist to overcome the inherit limitation of the phytoremediation technique when poorly mobile soil metals are of interest. In the present study, the influence of root exudates on the rhizosphere chemistry of soil and consequential metal uptake were investigated following culture of vetiver grass (Vetiveria zizanioides), recognized as a promising plant for land stabilization, in three different long-term contaminated soils and one non-contaminated control soil. The soil solution pH increased (0.3-1.1 units) following vetiver grass culture and dissolved organic carbon (DOC) also significantly increased in all soils with the highest increase in PP02 (23 to $173mg\;L^{-1}$). Chemical changes are contributed to root exudation by vetiver grass when exposed to high concentration of heavy metals. Chemical changes, consequently, influenced metal (Cd, Cu, Pb, and Zn) solubility and speciation in the rhizosphere. The highest solubility was observed for soil Ko01 (eg. 2091 and $318{\mu}g\;L^{-1}$ for Cd and Pb, respectively). Initial heavy metal solubility in soils varied with soil and either increased or decreased following vetiver grass culture depending on the soil type. An increase in pH following plant culture generally resulted in a decrease in metal solubility, while elevated DOC due to root exudation resulted in an increase in metal solubility via the formation of metal-DOC complexes. Donnan speciation demonstrated a significant decrease in free Cd and Zn in the rhizosphere and the concentration of Cd, Pb, and Zn in vetiver grass shoot was highly correlated with soluble concentration rather than total soil metal concentration.

일반적으로 근권부로 알려진, 토양과 뿌리 사이의 계면(soil-root interface)에서 일어나는 주요 기작에 대한 세부적 이해는 성공적인 phytoremediation 기술을 위해 특정 식물의 적용 가능성을 평가하는데 있어 매우 중요하다. 가령 어떤 식물은 토양중 낮은 중금속 유효도라는 제한인자를 극복하기 위해 근권부에서 특정 기작을 일으키기도 한다. 본 연구는 토양 고정 (land stabilization)에 탁월한 효과를 보이고 있는 vetiver grass(Vetiveria zizanioides)를 중금속으로 오염된 3가지의 다른 토양에 재배함으로써, 식물 뿌리가 근권부 토양의 화학적 특성에 미치는 영향과 이에 따른 식물의 중금속 흡수 특성을 조사하였다. Vetiver grass 재배 후 근권부 토양의 토양수 pH는 시험에 이용된 모든 토양에서 0.3-1.1 만큼 증가하였고, 토양수 중 유기탄소의 함량도 $23mg\;L^{-1}$ 에서 $173mg\;L^{-1}$로 가장 많이 증가한 PP02 토양을 비롯해서 모든 토양에서 증가하였다. 이와 같은 근권부 토양수의 화학적 변화는 중금속 오염토양에 노출된 vetiver grass의 뿌리에서 나온 분비물(exudates)에서 비롯된 것이다. 결과적으로 근권부 토양수의 화학적 특성 변화는 중금속(카드뮴, 납, 구리, 아연) 유효도 및 화학종 변화에 영향을 미쳤다. 중금속의 최초 유효도는 시험에 이용된 토양의 종류에 따라 달랐으며 vetiver grass 재배 후 이 유효도의 변화 또한 토양 종류의 영향을 받아 증가 또는 감소하였다. 가장 높은 중금속 유효도를 보인 토양은 Ko01 토양으로 토양수 중 카드뮴과 납의 농도가 각각 $2,091{\mu}g\;L^{-1}$, $318{\mu}g\;L^{-1}$ 이었다. 일반적으로 vetiver grass에 의해 증가한 pH는 중금속 유효도를 감소시켰고, 반면에 증가한 유기탄소는 토양중 중금속과 복합물질을 형성하면서 토양수 중 중금속의 농도를 높였다. Donnan speciation 기술을 이용한 화학종 분리 결과 토양수 중 순이온으로 존재하는 카드뮴과 아연의 농도가 현저히 감소하였고, vetiver grass에 의하여 체내에 축적된 중금속의 함량은 토양중 중금속 총함량이 아닌 토양수 중 중금속 유효도와 깊은 관계를 보였다.

Keywords

References

  1. Almas, A. R., M. B. McBride, B. R. Singh. 2000. Solubility and lability of cadmium and zinc in two soils treated with organic matter. Soil Science 165:250-259 https://doi.org/10.1097/00010694-200003000-00007
  2. Asao, T., K. Hasegawa, Y. Sueda, K. Tomita, K. Taniguchi, T. Hosoki, M.H.R. Pramanik, and Y. Matsui. 2003. Autotoxicity of root exudates from taro. Scientia Horticulturae 97(3-4):389-396 https://doi.org/10.1016/S0304-4238(02)00197-8
  3. Ashley, P. M., and B. G. Lottermoser. 1999. Arsenic contamination at the Mole River mine, northern New South Wales. Austr. J. Earth Sci. 46:861-874 https://doi.org/10.1046/j.1440-0952.1999.00748.x
  4. Awad, F., V. Romheld, and H. Marschner. 1994. Effect of root exudates on mobilization in the rhizosphere and uptake of iron by wheat plants. Plant and Soil 165:213-218 https://doi.org/10.1007/BF00008064
  5. Brooks, R.,R., J. Lee, R.D. Reeves, and T. Jaffre. 1997. Detection of nickeliferous rocks by analysis of herbarium species of indicator plants. J. Geochem. Explor. 7:49-57 https://doi.org/10.1016/0375-6742(77)90074-7
  6. Cartwright, R., R. H. Merry, and K. G. Tiller. 1976. Heavy metal contamination of soils around a lead smelter at Port Pirie, South Australia. Austr. J. Soil Res. 15:69-81 https://doi.org/10.1071/SR9770069
  7. Chantachon, S., M. Kruatrachue, P. Pokethitiyook, S. Upatham, S. Tantanasarit, and V. Soonthornsarathool. 2004. Phytoextraction and accumulation of lead from contaminated soil by vetiver grass: Laboratory and simulated field study. Water, Air, and Soil Pollu. 154(1-4):37-55 https://doi.org/10.1023/B:WATE.0000022926.05464.74
  8. Chen, H. M., C. R. Zheng, C. Tu, and Z. G. Shen. 2000. Chemical methods and phytoremediation of soil contaminated with heavy metals. Chemosphere 41(1-2):229-234 https://doi.org/10.1016/S0045-6535(99)00415-4
  9. Chen, Z, K-R. Kim, G. Owens, and R. Naidu 2007. Determination of carboxylic acids from plant root exudates by ion exclusion chromatography-electrospray ionization mass spectrometry. Submitted to Anal. Chim. Acta
  10. Clark, M. W., S. R. Walsh, and J. V. Smith. 2001. The distribution of heavy metals in an abandoned mining area; a case study of Strauss Pit, the Drake mining area, Australia: Implications for the environmental management of mine sites. Environ. Geol. 40(6):655-663 https://doi.org/10.1007/s002549900073
  11. Cobbett, C. S., and P. B. Goldsbrough. 2000. Mechanisms of metal resistance: Phytochelatins and Metallothioneins. p. 247-270 In I. Raskin, B.D. Ensley (ed.) Phytoremediation of toxic metals. New York, A wiley-interscience publication
  12. Epstein, A. L., C. D. Gussman, M. J. Blaylock, U. Yermiyahu, J. W. Huang, Y. Kapulnik, and C. S. Orser. 1999. EDTA and Pb-EDTA accumulation in Brassica Juncea grown in Pb-amended soil. Plant and soil 208:87-94 https://doi.org/10.1023/A:1004539027990
  13. Feng, M-H., X-Q. Shan, S. Zhang, and B. Wen. 2005. A comparison of the rhizosphere-based method with DTPA, EDTA, $CaCl_{2}$, and $NaNO_{3}$ extraction methods for prediction of bioavailability of metals in soil to barley. Environ. Pollut. 137(2):231-240 https://doi.org/10.1016/j.envpol.2005.02.003
  14. Hees, P. A. Wv., U. S. Lundstrom, and R. Giesler. 2000. Low molecular weight organic acids and their complexes in soil solution-composition, distribution and seasonal variation in three podzolized soils. Geoderma 94:173-200 https://doi.org/10.1016/S0016-7061(98)00140-2
  15. Herbert, B. E., and P. M. Bertsch. 1995. Characterization of dissolved and colloidal organic matter in soil solution: a review. p 63-88. In W.W. McFee, J.M. Kelly, (ed.) Carbon forms and functions in forest soils. Madison, Soil science society of America
  16. Hinsinger, P., C. Plassard, and B. Jaillard. 2005. Rhizosphere: A new frontier for soil biogeochemistry. J. Geochem. Explo. 88:210-213
  17. Jones, D. L. 1998. Organic acids in the rhizosphere - a critical review. Plant and Soil 205:25-44 https://doi.org/10.1023/A:1004356007312
  18. Keller, C., D. Hammer, A. Kayser, W. Richner, M. Brodbeck, and M. Sennhauser. 2003. Root development and heavy metal phytoextraction efficiency: comparison of different plant species in the field. Plant and Soil 249(1):67-81 https://doi.org/10.1023/A:1022590609042
  19. Kim, K-R., G. Owens, and R. Naidu. 2007a. Chemodynamics of heavy metals in long-term contaminated soils: II. Metal speciation in soil solution. Submitted to Sci. Total Environ
  20. Kim, K-R, G. Owens, and R. Naidu. 2007b. Chemodynamics of heavy metals in long-term contaminated soils: III. Influence of plant roots on soil solution composition in the rhizosphere. Submitted to Geoderma
  21. Kim, K-R, G. Owens, M. N. V. Prasad, and R. Naidu. 2007c. Lead induced organic acid exudation and citrate enhanced Pb uptake in hydroponic system. Submitted to Plant and Soil
  22. Knight, B., F. J. Zhao, S. P. McGrath, and Z. G. Shen. 1997. Zinc and cadmium uptake by the hyperaccumulator Thlaspi caerulescens in contaminated soils and its effects on the concentration and chemical speciation of metals in soil solution. Plant and soil 197:71-78 https://doi.org/10.1023/A:1004255323909
  23. Luo, Y. M., P. Christie, and A. J. M. Baker. 2000. Soil solution Zn and pH dynamics in non-rhizosphere soil and in the rhizosphere of Thlaspi caerulescens grown in a Zn/Cd-contaminated soil. Chemosphere 41(1-2):161-164 https://doi.org/10.1016/S0045-6535(99)00405-1
  24. McBride, M., S. Sauve, and W. Hendershot. 1997. Solubility control of Cu, Zn, Cd and Pb in contaminated soils. Eur. J. Soil Sci. 48:337-346 https://doi.org/10.1111/j.1365-2389.1997.tb00554.x
  25. Miller, W. P., and D. M. Miller. 1987. A micro pipette method for soil mechanical analysis. Commun. Soil Sci. Plant Anal. 18:1-15 https://doi.org/10.1080/00103628709367799
  26. Naidu, R., and R. D. Harter. 1998. Effect of different organic ligands on cadmium sorption by and extractability from soils. Soil Sci. Soc. Am. J. 62:644-650 https://doi.org/10.2136/sssaj1998.03615995006200030014x
  27. Naidu, R., M. Megharaj, and G. Owens. 2003. Recyclable urban and industrial waste - benefits and problems in agricultural use. In: P. Schjonning, S. Emholt, B.T. Christensen (ed.) Managing soil quality - challenges in modern agriculture. CABI Publishing, CABI International, Wallingford, Oxon
  28. Nelson, D.W., and L. E. Sommers. 1996. Total carbon, organic carbon, and organic matter. p. 961-1110. In A.L. Page (ed.) Methods of soil analysis, Agronomy
  29. Nian, H., M. Y. Zheng, J. A. Sung, J. C. Zhi, and H. Matsumoto. 2002. A comparative study on the aluminium- and copper-induced organic acid exudation from wheat roots. Physiologia Plantarum 116(3):328-335 https://doi.org/10.1034/j.1399-3054.2002.1160307.x
  30. Onyatta, J.O., and P. M. Huang. 2003. Kinetics of cadmium release from selected tropical soils from Kenya by low-molecular-weight organic acid. Soil Sci. 168(4):234-252 https://doi.org/10.1097/00010694-200304000-00002
  31. Pichtel, J., H. T. Sawyerr, and K. Czarnowska. 1997. Spatial and temporal distribution of metals in soils in Warsaw, Poland. Environ. Pollut. 98(2):169-174 https://doi.org/10.1016/S0269-7491(97)00131-0
  32. Quartacci, M. F., A. Argilla, A. J. M. Baker, and F. Navari-Izzo. 2005. Phytoextraction of metals from a multiply contaminated soil by Indian mustard. Chemosphere. 63(6):918-925 https://doi.org/10.1016/j.chemosphere.2005.09.051
  33. Randloff, B., K. Walsh, and A. Melzer. 1995. Direct revegetation of coal tailing at BHP, Saraji Mine Darwin, Australia. p 849-854
  34. Salt, D. E., M. Blaylock, P. B. A. N. Kumar, V. Dushenkov, B. D. Ensley, I. Chet, and I. Raskin. 1995. Phytoremediation: a novel strategy for the removal of toxic metals from the environment using plants. Biotechnol. 13:468-474 https://doi.org/10.1038/nbt0595-468
  35. Sauve, S., M. B. McBride, W. A. Norvell, and W. H. Hendershot. 1997. Copper solubility and speciation of in situ contaminated soils: Effects of copper level, pH and organic matter. Water, Air and Soil Pollut. 100(1-2):133-149 https://doi.org/10.1023/A:1018312109677
  36. Sauve, S., W. A. Norvell, M. B. McBride, and W. H. Hendershot. 2000. Speciation and complexation of cadmium in extracted soil solutions. Environ. Sci. Technol. 34(2):291-296 https://doi.org/10.1021/es990202z
  37. Temminghoff, E. J. M., A. C. C. Plette, R. V. Eck, and W. H. V. Riemsdijk. 2000. Determination of the chemical speciation of trace metals in aqueous systems by the Wageningen Donnan Membrand Technique. Anal. Chim. Acta 417:149-157 https://doi.org/10.1016/S0003-2670(00)00935-1
  38. Temminghoff, E. J. M., S. E. A. T. M. Vd. Zee, and F. A. Md. Haan. 1998. Effects of the dissolved organic matter on the mobility of copper in a contaminated sandy soil. Eur. J. Soil Sci. 49:617-628 https://doi.org/10.1046/j.1365-2389.1998.4940617.x
  39. Thibault, D. H., and M. I. Sheppard. 1992. A disposable system for soil pore-water extraction by centrifugation. Commun. Soil Sci. Plant Anal. 23(13&14):1629-1641 https://doi.org/10.1080/00103629209368692
  40. Truong, P. N., M. McDowell, and I. Christiansen. 1995. Stiff grass barrier with vetiver grass. A new approach to erosion and sediment control. Rockhamton, Australia. p. 301-304
  41. US EPA. Method 3051a: Microwave assisted acid dissolution of sediments, sludges, soils, and oils 1997 2nd ed. U.S. Environmental Protection Agency, U.S. Government Printing Office, Washington, DC
  42. Vassil, A. D., Y. Kapulnik, I. Raskin, and D. E. Salt. 1998a. Role of EDTA in lead transport and accumulation by Indian mustard. Plant Physiol. 117(2):447 https://doi.org/10.1104/pp.117.2.447
  43. Vassil, A. D., K. Yoram, R. Ilya, and E. S. David. 1998b. The Role of EDTA in lead transport and accumulation by Indian mustard. Plant physiol. 117:447-453 https://doi.org/10.1104/pp.117.2.447
  44. Vulkan, R., F-J. Zhao, V. Barbosa-Jefferson, S. Preston, G. I. Paton, E. Tipping, and S. P. McGrath. 2000. Copper speciation and impacts on bacterial biosensors in the pore water of coppercontaminated soils. Environ. Sci. Technol. 34(24):5115-5121 https://doi.org/10.1021/es0000910
  45. Wang, J., F-J. Zhao, A. A. Meharg, A. Raab, J. Feldmann, and S. P. McGrath. 2002. Mechanisms of arsenic hyperaccumulation in Pteris vittata. uptake kinetics, interactions with phosphate, and arsenic speciation. Plant physiol. 130:1552-1561 https://doi.org/10.1104/pp.008185
  46. Weng, L., E. J. M. Temminghoff, S. Lofts, E. Tipping, and W. H. Van Riemsdijk. 2002. Complexation with dissolved organic matter and solubility control of heavy metals in a sandy soil. Environ. Sci. Technol. 36(22):4804-4810 https://doi.org/10.1021/es0200084
  47. Wenzel, W. W., M. Bunkowski, M. Puschenreiter, and O. Horak. 2003. Rhizosphere characteristics of indigenously growing nickel hyperaccumulator and excluder plants on serpentine soil. Environ. Pollut. 123(1):131-138 https://doi.org/10.1016/S0269-7491(02)00341-X
  48. Xia, H. P. 2004. Ecological rehabilitation and phytoremediation with four grasses in oil shale mined land. Chemosphere 54:345-353 https://doi.org/10.1016/S0045-6535(03)00763-X
  49. Zhang, H., F. Zhao, B. Sun, W. Davison, and S. P. McGrath. 2001. A new method to measure effective soil solution concentration predicts copper availability to plants. Environ. Sci. Technol. 35:2602-2607 https://doi.org/10.1021/es000268q