Journal of Applied Biological Chemistry

The Korean Society for Applied Biological Chemistry (한국응용생명화학회)
권호 표지
DOI QR코드

DOI QR Code

Effects of free metal ions and organo-metal complexes on the absorption of lead and cadmium by plants

식물에 의한 납, 카드뮴 흡수 기작에 미치는 자유이온 및 유기산-중금속 복합체의 영향

  • Lee, Mina (Department of Smart Agro-Industry, Gyeongsang National University) ;
  • Seo, Byounghwan (Soil & Fertilizer Management Division, Department of Agricultural Environment, National Institute of Agricultural Science, Rural Development Administration) ;
  • Kim, Kwon-Rae (Department of Smart Agro-Industry, Gyeongsang National University)
  • Received : 2021.04.19
  • Accepted : 2021.05.25
  • Published : 2021.06.30
Download PDF
⟨ Previous Next ⟩

Abstract

Heavy metals exist in soils in various chemical forms including free metal ions and organo-metal complexes. The ratio of free metal ions has been known to be highly associated with the plant absorption of heavy metals. This study aims to understand the effect of free ions and organo-metal complexes on the absorption of lead (Pb) and cadmium (Cd) by plants. For this, lettuce grown in a hydroponic system for 28 days was consequently grown another 48 hours using Pb and Cd solutions. The ratios of free ion to organo-metal complexes in the solutions were adjusted at 100:0, 90:10, 70:30, 60:40 by four different organic acids (citric, oxalic, acetic, and humic acid). After that, the concentration of Pb and Cd in lettuce were analyzed. The Pb and Cd absorption by lettuce was more relied on the types of organic acids treated and the type of metals rather than the ratio of free metal ions. For example, citric acid increased the Pb absorption while it decreased the Cd absorption by lettuce. There was no significant relationship between free metal ion ratios and both Pb and Cd uptake by lettuce. It could be explained that citric acid, a relatively higher molecular weight organic acid, has higher ion binding capacity, so it forms organo-Pb complex easily due to the higher affinity of Pb on the binding site in comparison with Cd. Consequently, this complexation would assist Pb uptake by lettuce.

토양 중 중금속은 자유이온, 유기산-중금속 복합체를 포함한 다양한 화학종으로 존재한다. 이 중 중금속 자유이온 비율은 식물체의 중금속 흡수와 밀접한 관련이 있는 것으로 알려져 있다. 본 연구는 중금속 자유이온과 유기산-중금속 복합체 존재 비율이 식물의 납, 카드뮴 흡수에 어떤 영향을 미치는지 알아보기 위하여 수행되었다. 이를 위해 순환식 양액재배 장치에서 28일간 키운 상추를 48시간 동안 납과 카드뮴 용액에 침지시키는 실험을 진행하였다. 침지 전 시트르산, 옥살산, 아세트산, 휴믹산을 이용해 납과 카드뮴 용액의 중금속 자유이온과 유기산-중금속 복합체의 비율이 100:0, 90:10, 70:30, 60:40이 되도록 조절하였다. 침지 후 상추 뿌리와 잎의 납, 카드뮴 농도를 분석한 결과, 용액 중 중금속 자유이온의 비율과 식물이 흡수한 납, 카드뮴 농도는 상관관계를 보이지 않았다. 반면에 처리한 유기산의 종류와 중금속 종류에 따른 차이가 더 큰 것으로 나타났다. 시트르산은 납 흡수는 증가시켰지만 카드뮴 흡수는 감소시켰다. 시트르산은 다른 유기산보다 상추의 납 흡수율을 높였는데 이는 시트르산이 분자량이 크기 때문에 중금속 이온과 복합체를 형성할 수 있는 용량이 더 크기 때문인 것으로 보인다. 그러므로 본 연구 결과는 식물에 의한 중금속 흡수가 단순히 자유이온의 양에 따라 달라지기 보다는 존재하는 유기산의 분자량에 의한 결합용량 차이가 중금속 종류에 따라 달리 작용하여 결정된다는 것을 보여준다.

Keywords

Acknowledgement

이 논문은 2020년도 경남과학기술대학교 박사후연수과정 지원 사업의 지원을 받아 연구되었음.

References

  1. Sungur A, Soylak M, Ozcan H (2014) Investigation of heavy metal mobility and availability by the BCR sequential extraction procedure: Relationship between soil properties and heavy metals availability. Chem Speciat Bioavailab 26: 219-230. doi: 10.3184/095422914X14147781158674
  2. Wang L, Sun X, Li S, Zhang T, Zhang W, Zhai P (2014) Application of organic amendments to a coastal saline soil in north China: Effects on soil physical and chemical properties and tree growth. PLOS ONE 9: e89185. doi: 10.1371/journal.pone.0089185
  3. Stevenson FJ (1994) Humus chemistry-genesis, composition, reactions, 2nd ed. Wiley, New York. doi: 10.1371/journal.pone.0089185
  4. Dalvi AA, Bhalerao SA (2013) Response of plants towards heavy metal toxicity: An overview of avoidance tolerance and uptake mechanism. Ann Plant Sci 2: 362-368
  5. Gul I, Manzoor M, Hashmi I, Bhatti MF, Kallerhoff J, Arshad M (2019) Plant uptake and leachig potential upon application of amendments in soil spiked with heavy metals (Cd and Pb). J Environ Manage 249: 1-6
  6. Meier S, Alvear M, Borie F, Aguilera P, Ginocchio R, Cornejo P (2012) Influence of copper on root exudate patterns in some metallophytes and agricultural plants. Ecotoxicol Environ Saf 75: 8-15. doi: 10.1016/j.ecoenv.2011.08.029
  7. Jia H, Lu H, Dai M, Hong H, Liu J, Yan C (2016) Effect of root exudates on sorption, desorption, and transport of phenanthrene in mangrove sediments. Mar Pollut Bull 15: 171-177. doi: 10.1016/j.marpolbul.2016.06.004
  8. Sauve S, McBride M, Hendershot W (1998) Soil solution speciation of lead(II): Effects of organic matter and pH. Soil Sci Soc Am J 62: 618-621. doi: 10.2136/sssaj1998.03615995006200030010x
  9. Wang H, Shan X, Liu T, Wie Y, Wen B, Zhang S, Han F, van Genuchten MT (2007) Organic acids enhance the uptake of lead by wheat roots. Planta 225: 1483-1494. doi: 10.1007/s00425-006-0433-7
  10. Clarholm M, Skyllberg U, Rosling A (2015) Organic acid induced release of nutrients from metal-stabilized soil organic metter-The unbutton model. Soil Biol Biochem 84: 168-176. doi: 10.1016/j.soilbio.2015.02.019
  11. Onyatta JO, Huang PM (2003) Kinetics of cadmium release from selected tropical soils from Kenya by low-molecular-weight organic acids. Soil Sci 168: 234-252. doi: 10.1097/01.ss.0000064888.94869.37
  12. Kim HS, Kim KR, Kim HJ, Yoon JH, Yang JE, Ok YS, Owens G, Kim KH (2015) Effect of biochar on heavy metal immobilization and uptake by lettuce (Lactuca sativa L.) in agricultural soil. Environ Earth Sci 74: 1249-1259 https://doi.org/10.1007/s12665-015-4116-1
  13. Han F, Shan X, Zhang S, Wen B, Owens G (2006) Enhanced cadmium accumulation in maize roots - The impact of organic acids. Plant Soil 289: 355-368 https://doi.org/10.1007/s11104-006-9145-9
  14. Kim KR, Owens G, Naidu R, Kwon SI, Kim KH (2009) Lead induced organic acid exudation and citrate enhanced Pb uptake in hydroponic system. Korean J Environ Agric 28: 146-157. doi: 10.5338/KJEA.2009.28.2.146
  15. Berne RM, Levy MN (1998) Physiology. Mosby, St Louis
  16. Lu L, Tian SK, Yang XE, Peng HY, Li TQ (2013) Improved cadmium uptake and accumulation in the hyperaccumulator Sedum alfredii: the impact of citric and tartaric acid. J Zhejiang Univ Sci B14: 106-114. doi: 10.1631/jzus.B1200211
  17. Kim MJ, Moon Y, Tou JC, Mou B, Waterland NL (2016) Nutritional value, bioactive compounds and health benefits of lettuce (Lactuca sativa L.). J Food Compos Anal 49: 19-34. doi: 10.1016/j.jfca.2016.03.004
  18. Park S, Kim KS, Kang D, Yoon H, Sung K (2013) Effects of humic acid on heavy metal uptake by herbaceous plants in soils simultaneously contaminated by petroleum hydrocarbons. Environ Earth Sci 68: 2375-2384 https://doi.org/10.1007/s12665-012-1920-8
  19. Shahid M, Pinelli E, Dumat C (2012) Review of Pb availability and toxicity to plants in relation with metal speciation; role of synthetic and natural organic ligand. J Hazard Mater 219-220: 1-12. doi: 10.1016/j.jhazmat.2012.01.060
  20. Nor YM, Cheng HH (1986) Chemical speciation and bioavailability of copper: Uptake and accumulation by eichornia. Environ Toxicol Chem 5: 941-947. doi: 10.1002/etc.5620051102
  21. Oustan S, Heidari S, Neyshabouri MR, Reyhanitabar A, Bybordi A (2011) Removal of heavy metals from a contaminated calcareous soil using oxalic and acetic acids as chelating agents. Ipcbee 8: 152-155
  22. Kim JO, Lee YW, Chung J (2013) The role of organic acids in the mobilization of heavy metals from soil. KSCE J Civ Eng 17: 1596-1602 https://doi.org/10.1007/s12205-013-0323-z
  23. Mnasri M, Ghabriche R, Fourati E, Zaier H, Sabally K, Barrington S, Lutts S, Abdelly C, Ghnaya T (2015) Cd and Ni transport and accumulation in the halophyte Sesuvium portulacastrum: Implication of organic acids in these processes. Front. Plant Sci 6: 156. doi: 10.3389/fpls.2015.00156
  24. Wang ST, Dong Q, Wang ZL (2017) Differential effects of citric acid on cadmium uptake and accumulation between tall fescue and Kentucky bluegrass. Ecotoxicol Environ Saf 145: 200-206. doi: 10.1016/j.ecoenv.2017.07.034
  25. Wu FB, Dong J, Qiong QQ, Zhang GP (2005) Subcellular distribution and chemical form of Cd and Cd-Zn interaction in different barley genotypes. Chemosphere 60: 1437-1446. doi: 10.1016/j.chemosphere.2005.01.071