Photon Factory Activity Report 2017 #35 (2018)
BL- 4A, BL-12C, AR-NW10A/2014G716

Distribution of zinc and/or cadmium treatments inGynura pseudochina (L.) DC. biomass
Bodin MONGKHONSIN1, Woranan NAKBANPOTE1,* and Akiko HOKURA2
1

Department of Biology, Faculty of Science, Mahasarakham University,Khamriang, Kantarawichai, Maha Sarakham 44150, Thailand
2
Department of Green and Sustainable Chemistry, Tokyo Denki University,
Senju-Asahicho, Adachi, Tokyo, 120-8551, Japan

1. Introduction
Gynura pseudochina (L.) DC. is a Zn/Cd
hyperaccumulative plant. The dose effects on themorphology and dry weight indicated that Cd toxicity wasalleviated by the Zn [1-2]. The concentrations of Zn and Cd
under the tolerance limits induced the plants to increase theirantioxidant activity. The main part distribution of Zn and Cd
was correlated with antioxidant activity in the biomass.
Confocal laser scanning microscopy (CLSM) and micro Xray fluorescence (µ-XRF) imaging revealed that theaccumulation of Zn and Cd in the cell wall involves
flavonoid compounds.
2. Experiment
Four week old healthy plants were selected and treatedwith Zn and/or Cd under a tissue culture system. The plant
samples were separately treated for two weeks the Zn
solution (1000 mg L-1), Cd solution (150 mg L-1) and Zn/Cdsolution (1000/150 mg L-1). Distributions of metals in theplant tissue were studied by μ-XRF imaging analysis. The
samples were prepared as a thin sample with a constant
thickness (200-300 µm) to obtain a precise elemental
distribution. X-ray beam energy of approximately 30 keV
was focused into a microbeam (1.8 x 2.1 mm2), step size (5 x5 mm) and a measurement time of 0.3 s per point. The X-ray
beam energy of 11.1 keV on the BL-4A. The Cd K-edge andZn K-edge XANES spectra were recorded in a fluorescentmode at the NW10A and BL-12C of KEK-PF.

Fig. 2: Zn K edge (A) and Cd K-edge (B) XANES spectra of
G. pseudochina treated with Zn (100 mg L-1), Cd (15 mg L-1),
and Zn plus Cd (100 mg L-1+15 mg L-1).
3. Result and Discussion
The µ-XRF imaging showed the distributions of K, Mn,Ca and Zn within the samples (Fig.1). The distributions ofZn and Cd in the stem and leaves were similar area in theepidermal cell and vascular tissue. The bulk plant samples
treated with Zn and/or Cd were measured for XANES
spectra (Fig.2). The Zn K edge and Cd K edge XANES
spectra and XANES fitting implied that Zn2+ and Cd2+ werecoordinated with oxygen and sulphur.
References[1] N. Panitlertumpai et al., J. Mol. Struct. 1036, 279 (2013).
[2] W. Nakbanpote et al., In Advanced Knowledge Applicationin Practice, ISBN: 978-953-307-141-1.
Acknowledgement
We express gratitude to the Photon Factory (PF) forresearch facilities at beamline 4A, 12C, and NW10A (Proposalnumber 2014G716) and are grateful to Prof. Dr. Izumi NAKAIfor the µ-XRF analysis at beamline BL37XU and sincerely
thank S. Mitsuo, S. Takada, Y. Yoshii, and W. Yamaoka for
helping with the µ-XRF and µ-XANES analyses.

Fig. 1: µ-XRF imaging of G. pseudochina treated with Zn(100 mg L-1). (a) show the XRF mapping of Zn, Mn, K andCa. (b) and (c) are photograph and SEM image of the stem.

Research Achievements
Mongkhonsin, B., Nakbanpote, W., Hokura, A.,
Nuengchamnong, N., Maneechai, S. (2016). Phenolic
compounds responding to zinc and/or cadmium treatments
in Gynura pseudochina (L.) DC. extracts and biomass.
Plant Physiology and Biochemistry. 109, 549-560.
* woranan.n@msu.ac.th