RESEARCH ARTICLE

 

Impact of metals on secondary metabolites production and plant morphology in vetiver grass (Chrysopogon zizanioides)

 

 

Funzani A. Melato; Thierry Regnier; Rob I. McCrindle; Ntebogeng S. Mokgalaka^*

Department of Chemistry, Tshwane University of Technology, Private Bag X680, Pretoria, 0001, South Africa

 

 

---

ABSTRACT

The impact of selected metals on the production of phenolic compounds was investigated in a pot trial experiment. One-month-old vetiver grass (Chrysopogon zizanioides) seedlings were exposed to different concentrations (0, 10, 50, 100, and 500 ppm) of As, Cr, Cu, Fe, Ni, Pb and Zn. All the plants except for those treated with As tolerated up to 500 ppm as they did not show any signs of stress such as wilting or necrosis. A significant decrease (>35 %) in the length of the plants treated with As, compared to the control, was observed at 50 ppm which further decreased with increasing As concentration. A serious case of phytotoxicity was observed at 500 ppm As as the plant could not survive. Total soluble phenolics content in vetiver plants increased with increasing concentration of metals in the growth medium. The amount of the cell wall-bound phenolics (2.01 to 5.84 mg GAE g^-1 DW) was higher than the total soluble phenolics (1.13 to 2.14 mg GAE g^-1 dry weight DW) and both increased with increasing metal concentrations. Morphological changes associated with metal-induced stress were also examined with a scanning electron microscope which revealed thickened cell walls, loss of cell shape, reduction of intercellular space and the closure of stomata in leaves of metal-exposed plants.

Keywords: Vetiver grass, toxic metals, phytotoxicity, phenolic compounds, morphological changes

---

 

 

Full text available only in PDF format.

 

Acknowledgements

The authors would like to thank the South African National Research Fund (NRF) and Tshwane University of Technology for financial support. We are most grateful to Mr. Roley Noffke of Hydromulch for providing all the vetiver grass at no cost.

 

References

1 N. Hamid and N. Bakhari, F. Jawad, Pak. J. Bot., 2010, 42, 239-246.         [ Links ]

2 P. Fatoba and E.G. Udoh, Ethnobotanical leaflets 12, 2008, 776-83.         [ Links ]

3 A. Michalak, Pol. J. Environ. Stud, 2006, 15, 523-530.         [ Links ]

4 D.H. Nies, Appl. Microbiol. Biot, 1999, 51, 730-750.         [ Links ]

5 H. Sarma, J. Environ. Sci. Technol, 2011, 4, 118-138.         [ Links ]

6 L.M. Sandalio, H.C. Dalurzo, M. Gomez, M.C. Romero-Puertas and L.A. del Rio, J. Exp. Bot., 2001, 52, 2115-2126.         [ Links ]

7 S. Singh and S. Sinha, Environ. Int, 2004, 30, 389-395.         [ Links ]

8 A. Schutzendubel and A. Polle, J. Exp. Bot., 2002, 53, 1351-1365.         [ Links ]

9 K. Gorecka, M. Cvikrova, U. Kowalska, J. Eder, K. Szafranska, R. Gorecki and K.M. Janas, Plant Physiol. Bioch, 2007, 45, 54-61.         [ Links ]

10 R.A. Dixton and N.L. Palva, Plant Cell, 1995, 7, 1085-1097.         [ Links ]

11 Y. Sakihama, M.F. Cohen, S.C. Grace and H. Yamasaki, Toxicology, 2002, 177, 67-80.         [ Links ]

12 J. Kovacik and B. Klejdus, Plant Cell, 2008, 27, 605-615.         [ Links ]

13 S. Surveswaran, Y. Cai, H. Corke and M. Sun, Food Chem. 2007, 102, 938-953.         [ Links ]

14 M. Bertrand and I. Poirier, Photosynthetica, 2005, 43, 345-353.         [ Links ]

15 B.B.M. Sridhar, S.V Diehl, F.X. Han,D.L. Monts and Y. Su, Environ. Exp. Bot., 2005, 54, 131-141.         [ Links ]

16 Q. Zhou and B.Yu, Plant Physiol. Bioch., 2010, 48, 417-425.         [ Links ]

17 N. Dudai, E. Putievsky, D. Chaimovitch and M. Ben-Hur, J. Eviron. Manage., 2006, 81, 63-71.         [ Links ]

18 V.L. Singleton and J.A. Rossi, Am. J. Enol. Viticult., 1965, 16, 144-158        [ Links ]

19 X. Liu, Y. Shen, L.. Laiqing, C. Ding and Q. Cai, Biotechnol. Adv., 2008, 27, 633-640.         [ Links ]

20 M.A. Rahman, H. Hasegawa, M.M. Rahman, M.N. Islam, M.A.M. Miah and A. Tasmen, Chemosphere, 2007, 67, 1072-1079.         [ Links ]

21 L.M. Walsh, M.E. Summer and D.R. Keeney, Environ. Health Persp., 1977, 19, 67-71.         [ Links ]

22 N. Aibibu, Y. Liu, G. Zeng, X. Wang, B. Chen, H. Song and L. Xu, Bioresource Technol., 2010, 101, 6297-6303.         [ Links ]

23 M.T. Fernandez, M.L. Mira, M.H. Florencio and K.R. Jennings, J. Inorg. Biochem., 2002, 92, 105-111.         [ Links ]

24 N. Gursoy, C. Sarikurkcu, M. Cengiz and M.H. Solak, Food and Chem. Toxicol., 2009, 47, 2381-2388.         [ Links ]

25 S. Connan and D.B. Stengel, Aquat. Toxicol., 2011, 104, 1-3.         [ Links ]

26 K. Turnnau, F.S. Henriques, T. Anielska, C. Renker and F. Buscot, Environ. Exp. Bot., 2007, 61,117-123.         [ Links ]

27 V.V. Lozovaya, T.A. Gorshkova, N.I. Rumyantseva, A.V. Ulanov, A.I. Valiera, E.V Yablokova, C. Mei and J.M. Widholm, Plant Sci., 2000, 152, 79-85.         [ Links ]

28 B.B.M. Sridhar, F.X. Han, S.V. Diehl, D.L. Monts and Y. Su, Braz. J. Plant Physiol., 2007, 19, 15-22.         [ Links ]

 

 

Received 2 May 2012
Revised 25 July 2012
Accepted 25 July 2012

 

 

* To whom correspondence should be addressed. E-mail: mokgalakans@tut.ac.za