Phytoremediation potential of

Sedum alfredii

Jenna McAleer

November 13, 2012

Presentation outline

I. S. alfredii description

II. Current role in phytoremediation

III. Hyperaccumulation mechanisms

IV. How to enhance phytoremediation potential

V. Future research

VI. Conclusion

Sedum alfredii Hance (Crassulaceae)

Physical description: - Clump-forming perennial herb, up to 40 cm tall

- Fast growth, large biomass

- Asexual reproduction (3-4 times/year)

- Yellow flowers (Chao et al. 2008: Xu et al. 2009; Zhu et al. 2009)

Distribution: - Native to Asia (China, Japan and Korea)

- Shady, moist forested slopes

- 2000-3000m; 35-85° F

- HE found in Zhejiang Province in eastern

China (old Pb/Zn mines)

(Yang et al. 2007; Liu et al. 2009; Xu et al. 2009)

forums.plant-seeds.idv.tw

sacu.org

Current role in phytoremediation

• HE S. alfredii hyperaccumulates Cd, Zn and Pb *Only known HA of both Zn and Cd that is not a member of the Brassicaceae family*

• Threshold values defining hyperaccumulation

– Cd: 100 mg/kg; Zn: 3,000 mg/kg; Pb: 1,000 mg/kg

(Deng et al. 2007; Huang et al. 2007; Deng et al. 2008; Liu et al. 2009; Zhu et al. 2009)

Current role in phytoremediation

(Sun et al. 2009; USGS Mineral Resources Program 2009)

- Urban wastewater used for agricultural irrigation in China since 1950’s

- Heavy metal contamination of agricultural soils

Hyperaccumulation mechanisms

• Obtaining metals from the soil - root foraging -heterogeneous Zn/Cd environment; 90% of root

biomass in metal rich patches

-S. alfredii had stronger Zn and Cd root foraging

than Thlaspi caerulescens

- adsorption to root surfaces important for removal of Zn

and Pb

• Uptake -Cd predicted to be taken up by Zn, Fe or Ca transporters -Arabidopsis halleri: Zn pathway; T. caerulescens: specific Cd

transporters and a high affinity Zn transporter

-S. alfredii: Ca transporters or channels

(Liu et al. 2009; Li et al 2010; Lu et al. 2010; Xiong et al. 2010)

Hyperaccumulation mechanisms

• Transport

-translocation of Cd via symplastic route into root

and then into shoot via xylem (driven by transpiration

from the leaves)

• Detoxification - Cd: Ca protects the roots of S. alfredii by competing for uptake transporters and by promoting GSH bio- synthesis; induced PCs

- Pb: increase in GSH synthesis (not PCs)

- rhizosphere microbes

(Lu et al. 2008; Lu et al. 2009; Gupta et al. 2010; Tian et al. 2011)

Hyperaccumulation mechanisms

• Storage in vacuole * Based on in vivo analysis by m-XRF and LA-ICPMS*

- Cd: HE- in parenchyma tissues (pith, cortex, and

mesophyll)

NHE- restricted within the vascular bundles

- Pb: largely found in cell walls

- Zn: localized in epidermal and vascular cells

(Yang et al. 2007; Tian et al. 2009; Tian et al. 2011)

How to increase phytoremediation

potential • Microbes

– Bacteria - 14 strains isolated (soil and endophytic)

- protect S. alfredii from metal toxicity and increase uptake and accumulation

of Zn, Cd, and Pb

– Fungi - Fusarium oxysporum

- enhanced metal bioavailability, uptake, and translocation

- increased root and shoot biomass

- increased chlorophyll synthesis

- ~ doubled phytoextraction potential of HE S. alfredii

(Xiong et al. 2008; Xinxian et al. 2010; Li and Wong 2011)

How to increase phytoremediation

potential • Compost

– Pig manure vermicompost (PMVC)

- 2-4 fold increase in shoot and root biomass of S.alfredii

- increased Cd phytoextraction

- did not impact soil microbes

• Chelators (EDTA and CA)

– Enhanced Pb accumulation in shoots

– Increased Cd accumulation in stems, leaves and shoots

– Negatively impacted plant growth (brown spots and/or death)

(Zhuang et al. 2007; Sun et al. 2009; Wang et al. 2009; Tian et al. 2012; Wang et al. 2012)

How to increase phytoremediation

potential

• Fertilizers

– Nitrogen increased chlorophyll content and Cd

accumulation in shoots

• Co-cropping

– S. alfredii + Zea mays = increased biomass and metal

phytoextraction of S. alfredii

– S. alfredii + Alocasia macrorrhiza = increased Zn

phytoextraction by S. alfredii

(Wu et al. 2007; Jiang et al. 2009; Zhu et al. 2011)

Future research

• More detailed investigation of different subpops of

S. alfredii

• Any other Sedum species? (S. jinianum)

• Phytoremediation potential in other locations?

• Further studies on post-HA processing of plant material - fertilizer or mulch

- crude bio-oil production - food crop biofortification

(Rascio and Navari-Izzo 2010; Yang et al. 2010)

Conclusion

• S. alfredii has been shown to hyperaccumulate Cd, Zn, and Pb

in polluted sites in China

– variation between subpopulations

• S. alfredii hyperaccumulation may be enhanced via addition of

microbes, compost, chelators, fertilizers and/or co-cropping

with non HA’ers

• Future research could lead to enhanced phytoremediation

potential and added benefits of harvested plant material

Sources • Chao, Y. E., Y. Feng, X. E. Yang, and D. Liu. 2008. Effect of long-term stress of high Pb/Zn levels on genomic variation of Sedum alfredii Hance. Bull Environ Contam Toxicol 81: 445-448.

•Deng, D. M., J. C. Deng, J. T. Li, J. Zhang, M. Hu, Z. Lin, and B. Liao. 2008. Accumulaiton of zinc, cadmium, and lead in four populations of Sedum alfredii growing on lead/zinc mine spoils. Journal of

Integrative Plant Biology 50(6): 691-698.

•Deng, D. M., W. S. Shu, J. Zhang, H. L. Zou, Z. Lin, Z. H. Ye, and M. H. Wong. 2007. Zinc and cadmium accumulation and tolerance in populations of Sedum alfredii. Environmental Pollution 147: 381- 386.

•Gupta, D. K., H. G. Huang, X. E. Yang, B. H. N. Razafindrabe, and M. Inouhe. 2010. The detoxification of lead in Sedum alfredii H. is not related to phytochelatins but the glutathione. Journal of Hazardous Materials 177: 437-444.

• Huang, H., T. Li, S. Tian, D. K. Gupta, X. Zhang, and X. Yang. 2007. Role of EDTA in alleviating lead toxicity in accumulator species of Sedum alfredii H. Bioresource Technology 99: 6088-6096.

• Jiang, C., Q. Wu, T. Sterckman, C. Schwartz, C. Sirguey, S. Ouvrard, J. Perriguey, and J. L. Morel. 2010. Co- planting can phytoextract similar amounts of cadmium and zinc to mono-cropping from contaminated soils. Ecological Engineering 36: 391-395.

• Li, T., Z. Di, E. Islam, H. Jiang, and X. Yang. 2010. Rhizosphere characteristics of zinc hyperaccumulator Sedum alfredii involved in zinc accumulation. Journal of Hazardous Materials 185: 818-823.

• Li, W. C., and M. H. Wong. 2011. Interaction of Cd/Zn hyperaccumulating plant (Sedum alfredii) and rhizosphere bacteria on metal uptake and removal of phenanthrene. Journal of Hazardous Materials 209-210: 421-433.

• Liu, F., Y. Tang, R. Du, H. Yang, Q. Wu, and R. Qiu. 2009. Root foraging for zinc and cadmium requirement in the Zn/Cd hyperaccumulator plant Sedum alfredii. Plant Soil 327: 365-375.

• Lu, L., S. Tian, X. Yang, T. Li, and Z. He. 2008. Cadmium uptake and xylem loading are active processes in the hyperaccumulator Sedum alfredii. Journal of Plant Physiology 166: 579-587.

• Lu, L., S. Tian, X. Yang, X. Wang, P. Brown, T. Li, and Z. He. 2008. Enhanced root-to-shoot translocation of cadmium in the hyperaccumulating ecotype of Sedum alfredii. Journal of Experimental Botany 59(11): 3203-3213.

Sources

• Lu, L., S. Tian, M. Zhang, J. Zhang, X. Yang, and H. Jiang. 2010. The role of Ca pathway in Cd uptake and translocation by the hyperaccumulator Sedum alfredii. Journal of Hazardous Materials 183: 22-28.

• Rascio, N. and F. Navari-Izzo. 2011. Heavy metal hyperaccumulating plants: How and why do they do it? And what makes them so interesting? Plant Science 180: 169-181.

• Sun, Y. B., Q. X. Zhou, J. An, W. T. Liu, and R. Liu. 2009. Chelator-enhanced phytoextraction of heavy metals from contaminated soil irrigated by industrial wastewater with the hyperaccumulator plant (Sedum alfredii Hance). Geoderma 150: 106-112.

• Tian, S. K., L. L. Lu, X. E. Yang, J. M. Labavitch, Y. Y. Huang, and P. Brown. 2009. Stem and leaf sequestration of zinc at the cellular level in the hyperaccumulator Sedum alfredii. New Phytologist 182: 116-126.

• Tian, S. K., L. L. Lu, X. E. Yang, H. G. Huang, P. Brown, J. Labavitch, H. B. Liao, and Z. L. He. 2011. The impact of EDTA on lead distribution and speciation in the accumulator Sedum alfredii by synchrotron X-ray investigation. Environmental Pollution 159: 782-788.

• Tian, S., L. Lu, J. Labavitch, X. Yang, Z. He, H. Hu, R. Sarangi, M. Newville, J. Commisso, and P. Brown. 2011. Cellular sequestration of cadmium in the hyperaccumulator plant species Sedum alfredii. Plant Physiology 157: 1914-1925.

• Tian, S., L. Lu, J. Zhang, K. Wang, P. Brown, Z. He, J. Liang, and X. Yang. 2011. Calcium protects roots of Sedum alfredii H. against cadmium-induced oxidative stress. Chemosphere 84: 63-69.

• USGS Mineral Resources Program. 2009. http://minerals.usgs.gov.

• Wang, K., J. Zhang, Z. Zhu, H. Huang, T. Li, Z. He, X. Yang, and A. Alva. 2012. Pig manure vermicompost (PMVC) can improve phytoremediation of Cd and PAHs co-contaminated soil by Sedum alfredii. Journal of Soil Sediments 12: 1089-1099.

• Wang, X., Y. Wang, Q. Mahmood, E. Islam, X. Jin, T. Li, X. Yang, and D. Liu. 2009. The effect of EDDS addition on the phytoextraction efficiency from Pb contaminated soil by Sedum alfredii Hance. Journal of Hazardous Materials 168: 530-535.

• Wu, Q. T., L. Hei, J. W. C. Wong, C. Schwartz, and J. L. Morel. 2007. Co-cropping for phyto-separation of zinc and potassium from sewage sludge. Chemospere 68: 1954-1960.

Sources • Xinxian, L., C. Xuemei, C. Yagang, W. J. Woon-Chung, W. Zebin, and W. Qitang. 2011. Isolation and characterization endophytic bacteria from hyperaccumulator Sedum alfredii Hance and their potential to promote phytoextraction of zinc polluted soil. World Journal of Microbiology and Biotechnology 27: 1197-1207. • Xiong, J., Z. He, D. Liu, Q. Mahmood, and X. Yang. 2008. The role of bacteria in the heavy metals removal and growth of Sedum alfredii Hance in an aqueous medium. Chemosphere 70: 489-494.

• Xiong, J. B., Q. Mahmood, and M. Yue. 2010. The potential of Sedum alfredii Hance of the biosorption of some metals from synthetic wastewater. Desalination 267: 154-159.

• Xu, L., S. Zhou, L. Wu , N. Li, L. Cui, Y. Luo, and P. Christie. 2009. Cd and Zn tolerance and accumulation by Sedum jinianum in East China. International Journal of Phytoremediation 11: 283-295.

• Yang, J. G., C. B. Tang, J. He, S. H. Yang, and M. T. Tang. 2010. Heavy metal removal and crude bio-oil upgrade from Sedum alfredii Hance harvest using hydrothermal upgrading. Journal of Hazardous Materials 179: 1037-1041.

• Yang, X. T. Li, J. Yang, Z. He, L. Lu, and F. Meng. 2007. Zinc compartmentation in root, transport into xylem, and absorption into leaf cells in the hyperaccumulating species of Sedum alfredii Hance. Planta 224: 185-195.

• Zhang, X., L. Lin, M. Chen, Z. Zhu, W. Yang, B. Chen, X. Yang, and Q. An. 2012. A nonpathogenic Fusarium oxysporum strain enhances phytoextraction of heavy metals by the hyperaccumulator Sedum alfredii Hance. Journal of Hazardous Materials 229-230: 361-370.

• Zhu, E., D. Liu, J. G. Li, T. Q. Li, X. E. Yang, Z. L. He, and P. J. Stoffella. 2011. Effect of nitrogen fertilizer on growth and cadmium accumulation in Sedum alfredii Hance. Journal of Plant Nutrition 34: 115- 126.

• Zhuang, P., Q. W. Yang, H. B. Wang, and W. S. Shu. 2007. Phytoextraction of heavy metals by eight plant species in the field. Water Air Soil Pollution 184: 235-242.

Quiz questions…

1. Name one metal that S. alfredii is capable of

hyperaccumulating.

2. What is one way that scientists have found to

increase the phytoremediation potential of S.

alfredii?

Quiz answers…

1. Cd, Zn, and Pb

2. Adding microbes (bacteria and/or fungi)

Adding compost

Adding chelators (EDTA and/or CA)

Adding fertilizers (nitrogen)

Co-cropping with non-hyperaccumulators