1 ARSENIC HYPERACCUMULATION BY PTERIS VITTATA L.

117 Pages·2011·0.65 MB·English

ARSENIC HYPERACCUMULATION BY PTERIS VITTATA L.- ARSENIC
TRANSFORMATION, UPTAKE AND ENVIRONMENTAL IMPACT

By

SHINY MATHEWS

A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL
OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF
DOCTOR OF PHILOSOPHY

UNIVERSITY OF FLORIDA

2011
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© 2011 Shiny Mathews

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To my daughter, Lisa Annie Johnson
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ACKNOWLEDGMENTS
I would like to take this opportunity to thank my advisor Dr. Lena Q. Ma for letting
me be a part of her group and for her support and encouragement. I am grateful to her
for the guidance provided both for my research and professional development. I would
also like to thank my committee members Dr. Bala Rathinasabapathi, Dr. Robert
Stamps, Dr. Charles Guy and Dr. Max Teplitski for their valuable suggestions and the
time they spent on ensuring the smooth progress of my research. I am grateful to Dr.
Tim Martin and Dr. Carlos Gonzales for the training provided on the pressure chamber. I
am obliged to Dr. Rao Mylavarapu, Dr. John Thomas and Dr. Andy Ogram for their help
in the research related aspects.
My research and lab training was very much influenced by the dedicated efforts of
our laboratory manager Dr. Uttam Saha. I thank him and Dr. Mrittunjai Srivastava and
their families for all the help from the day I arrived in the U.S. till now. The
Biogeochemistry of Trace Metals group was like a huge family to me. At this moment I
thank my friends Anhui, Shuhe, Xiaowen, Shawn, Dr. Ding, Dr. Ullah, Edmund, Xin,
Hao, Tan, Jay, Piyasa, Ling and Ying for ongoing support in research and in personal
matters. Special thanks also to Moshe, Akua and Abel for their help in research.
My roommates and friends in Gainesville played a major role in creating a home
away from home atmosphere. I would like to convey my gratitude to Pragyan, Bini, Biji,
Georgy, Vivek, Sudhamshu, Ramesh, Nithin, Bharath, Manu, Anand, Rajesh, Phalgun,
Deepak and all my friends.
I thank my previous supervisors Dr. P. Venugopalan, Dr. L Suseela Devi, Dr.
Suguna Yesodharan and Dr. Sivanandan Achary for their encouragement and help
during the application process to the University of Florida.
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I would never have been able to achieve anything in my life without the love and
support of my parents, in-laws and husband. With their constant encouragement and
prayers I have been able to achieve my goal. I would like to take this opportunity to
express my love to them and dedicate this research to my family especially to my
daughter, Lisa, who learned to understand my responsibilities and my absence
throughout these 4 years.
I thank God for keeping me safe and strong and for helping me achieve my
objectives.
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TABLE OF CONTENTS

page
ACKNOWLEDGMENTS .................................................................................................. 4
LIST OF FIGURES .......................................................................................................... 9
ABSTRACT ................................................................................................................... 11
CHAPTER
1 INTRODUCTION .................................................................................................... 13
2 REVIEW OF LITERATURE .................................................................................... 16
Arsenic: Origin and Occurrence .............................................................................. 16
Arsenate and Arsenite in the Environment .............................................................. 17
Arsenate Reduction .......................................................................................... 18
Arsenite Oxidation ............................................................................................ 20
Applications of Arsenic ............................................................................................ 22
Toxicity and Health Effects ..................................................................................... 23
Inorganic Arsenic .............................................................................................. 23
Organic Arsenic ................................................................................................ 24
Arsenic Remediation ............................................................................................... 24
Pteris vittata in Phytoremediation ........................................................................... 27
Life Cycle .......................................................................................................... 28
Physiology ........................................................................................................ 28
Arsenic Uptake ................................................................................................. 29
Microflora Associations..................................................................................... 30
Insect Deterrence ............................................................................................. 31
3 ARSENIC TRANSFORMATION IN THE GROWTH MEDIA OF P. VITTATA-
THE ROLE OF MICROBES OR ROOT ENZYMES ................................................ 32
Arsenic Transformations ......................................................................................... 32
Materials and Methods ............................................................................................ 33
Experimental Setup .......................................................................................... 33
Arsenic Speciation under Natural Conditions ................................................... 34
Arsenic Speciation under Sterile Conditions ..................................................... 35
Arsenic Speciation in Sonicate Extract ............................................................. 36
Arsenic Analysis ............................................................................................... 37
Data Analysis ................................................................................................... 38
Results and Discussion ........................................................................................... 38
Arsenic Speciation under Natural Conditions ................................................... 38
Media arsenic speciation............................................................................ 38
Biomass arsenic speciation ........................................................................ 39
Arsenic Speciation under Sterile Conditions ..................................................... 45
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Arsenite Oxidation in Sonicated Extract ........................................................... 47
Future Research ..................................................................................................... 49
4 ARSENIC TRANSFORMATION AND SPECIATION IN PTERIS VITTATA
BIOMASS AND XYLEM SAP .................................................................................. 51
Arsenic Speciation .................................................................................................. 51
Materials and Methods ............................................................................................ 53
Results and Discussion ........................................................................................... 53
Xylem Sap Arsenic Speciation ......................................................................... 54
Biomass Arsenic Speciation ............................................................................. 54
Research Findings .................................................................................................. 56
5 UPTAKE AND TRANSLOCATION OF ARSENITE AND ARSENATE BY
PTERIS VITTATA L.: EFFECTS OF GLYCEROL, ANTIMONITE AND SILVER .... 59
Arsenic Uptake and Translocation .......................................................................... 59
Materials and Methods ............................................................................................ 62
Experimental Setup .......................................................................................... 62
Time Dependent Uptake Study ........................................................................ 63
Competition and Inhibition Study ...................................................................... 63
Data Analysis ................................................................................................... 64
Results and Discussion ........................................................................................... 64
Effects of Glycerol and SbIII on AsIII Uptake .................................................... 65
Effects of Silver Nitrate on AsIII Uptake ........................................................... 68
AsIII Oxidation in the Media and P. vittata ........................................................ 76
Research Findings .................................................................................................. 80
6 ARSENIC REDUCED SCALE-INSECT INFESTATION ON ARSENIC
HYPERACCUMULATOR PTERIS VITTATA L. ...................................................... 81
Insect Detterence .................................................................................................... 81
Materials and Methods ............................................................................................ 85
Experiment Setup ............................................................................................. 85
Arsenic Treatment and Scale Counting ............................................................ 85
Chemical and Data Analysis ............................................................................. 86
Results and Discussion ........................................................................................... 86
Arsenic Toxicity in Scales ................................................................................. 86
Arsenic Concentration and Scale Death ........................................................... 87
Findings and Future Directions ............................................................................... 91
7 CONCLUSIONS AND FUTURE DIRECTIONS ...................................................... 93
APPENDIX
A EFFECT OF ARSENIC LOADING ON ARSENIC HYPERACCUMULATION BY
PTERIS VITTATA ................................................................................................... 97
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B COMPARISON OF ANTIMONY ACCUMULATION IN PTERIS VITTATA AND
PTERIS ENSIFORMIS ............................................................................................ 99
LIST OF REFERENCES ............................................................................................. 101
BIOGRAPHY ............................................................................................................... 117

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LIST OF FIGURES
Figure page

1-1 pE/pH diagram of As in water system at 25°C .................................................... 18
1-2 Pathways for the reductive dissolution of sorbed arsenic. .................................. 19
1-3 Hypothetical model of an arsenite oxidase enzyme ............................................ 21
3-1 One month old P. vittata sporophytes ................................................................. 34
3-2 Propagation of P. vittata under sterile conditions ................................................ 36
3-3 As speciation when treated with 0.10 mM AsIII for 24 h. .................................... 41
3-4 Arsenic speciation when treated with 0.27 mM AsIII for 8 d. .............................. 43
3-5 Arsenic speciation when treated with0.27 mM AsV for 8 d ................................. 44
3-6 As speciation when treated with 0.10 mM AsIII for 1 and 14 d under sterile
conditions.. ......................................................................................................... 48
3-7 As speciation in the media with root sonicate of P. vittata .................................. 50
4-1 Schematic of different parts of P. vittata. ............................................................ 57
4-2 Scholander pressure chamber ............................................................................ 57
4-3 Arsenic speciation in the sap and tissue of P. vittata treated with 0.1 mM AsV
for 8 d ................................................................................................................. 58
5-1 Arsenic speciation in the media and root of P. vittata.exposed to 0.1 mM AsIII
or AsV for 1, 2, 4, 6 and 24 h. ............................................................................. 66
5-2 Effect of glycerol on arsenic speciation in P. vittata when treated with 0.1 mM
AsIII for 1 h ......................................................................................................... 69
5-3 Effect of glycerol on arsenic speciation in P. vittata when treated with 0.1 mM
AsV for 1 h .......................................................................................................... 70
5-4 Effect of SbIII on arsenic speciation in P. vittata when treated with 0.1 mM
AsIII for 1 h ......................................................................................................... 71
5-5 Effect of SbIII on arsenic speciation in P. vittata when treated with 0.1 mM
AsV for 1 h .......................................................................................................... 72
5-6 Concentration of Sb in P. vittata when treated with 0.1 mM AsIII and different
concentrations of SbIII for 1 h ............................................................................. 73
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5-7 Effect of AgNO on arsenic speciation in P. vittata when treated with 0.1 mM
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AsIII for 1 h. ........................................................................................................ 77
5-8 Effect of AgNO on arsenic speciation in P. vittata when treated with 0.1 mM
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AsV for 1 h. ......................................................................................................... 78
5-9 Effect of AgNO on arsenic speciation in the fronds and roots of P. vittata
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after exposing to 0.1 mM arsenic for 2 h ............................................................ 79
6-1 Scale Insect: Saissetia neglecta ......................................................................... 84
6-2 The total number of fallen-scale and intact-scale on the fronds of P. vittata
after 1 week of arsenic exposure . ...................................................................... 88
6-3 Arsenic concentrations in the fronds of P. vittata, fallen-scales and intact-
scales. ................................................................................................................ 92
A-1 Effect of arsenic loading when treated with As for 15 d on frond arsenic
concentration in P. vittata ................................................................................... 97
A-2 Effect of arsenic loading when treated with As for 15 d on root arsenic
concentration in P. vittata. .................................................................................. 98
B-1 Concentration of Sb in P. vittata when treated with different concentrations of
Sb ....................................................................................................................... 99
B-2 Concentration of Sb in P. ensifomis when treated with different
concentrations of Sb ......................................................................................... 100

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