G E N O T Y P I C A N D P H Y L O G E O G R A P H I C I N V E S T I G A T I O N O F I N D I G E N O U S A N D A L I E N T A M A R I X S P E C I E S I N S O U T H E R N A F R I CA Samalesu Guelor Mayonde A Dissertation submitted to the Faculty of Science, University of Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science School of Animal Plant and Environmental Sciences Johannesburg, August 2013 DECLARATION I declare that this dissertation is my own, unaided work. It is being submitted for the degree of Masters of Science at the University of the Witwatersrand, Johannesburg. It has not been submitted before for any degree or any examination at any other University. _______________________________________ Samalesu Guelor MAYONDE ____________________________day of ________________________20________________ i ABSTRACT Tamarix (Tamaricaceae) is from the Old World, but has become naturalized and invaded other parts of the world including South Africa. Tamarix usneoides is the only species native to southern Africa, but the exotic species T. aphylla, T. chinensis, T. parviflora and T. ramosissima have been reported to be present in South Africa and these Tamarix species are hypothesized to be hybridizing among themselves and with the indigenous T. usneoides. Among the exotic species, T. chinensis, T. ramosissima and their putative hybrids have become invasive. Tamarix usneoides is used in southern African mines for phytoremediation as it has the ability to hyper- accumulate sulphate and heavy metals from Acid Mine Drainage from Tailing Storage Facilities and excretes gypsum (CaSO4). Tamarix species are morphologically and ecologically similar, making them difficult to distinguish and hybridization adds to the taxonomic confusion. Identification of Tamarix species in South Africa is of great importance because of the invasive potential of T. chinensis, T. ramosissima and their putative hybrids, and also because of the potential usefulness of T. usneoides. This investigation aimed to identify populations of pure T. usneoides that can be cloned for cultivation for phytoremediation on the mines, and to reveal the geographic origin of the invasive species to facilitate a biological control programme. Nuclear (ITS) and plastid (trnS-trnG) DNA sequence data and the multilocus Amplified Fragment Length Polymorphisms (AFLPs) markers were used in this study to characterize southern African Tamarix species and their putative hybrids. Phylogenetic analyses and population genetic structure confirm the presence of three Tamarix species in South Africa (T. chinensis, T. ramosissima and T. usneoides) with admixed individuals (Tamarix hybrids). The indigenous T. usneoides is clearly genetically distant from the alien species T. chinensis and T. ramosissima. Although the exotic species remain largely unresolved in the phylogenies, they are distinctly separated through AFLP markers. The Tamarix infestation in South Africa is dominated by hybrids between T. chinensis and T. ramosissima, and the parent species match their counterparts from their places of origin in Asia. These places of origin in Asia can provide the source of potential biological control agents. Some remote populations, e.g. Witbank, Goodhouse and Henkries in the Northern Cape Province/South Africa at the border with Namibia, of pure breeding T. usneoides have been identified and these should be used as a source of genetic material that can be propagated for planting on the mines for phytoremediation programmes. ii DEDICATION I dedicate this work to my family, particularly my father Mukazu Robert MAYONDE and my mother Musenga Bernadette Musumba for always telling me that YES you can do it. To my sisters Samba Lillian Mayonde, Kainda Seraphine Mayonde, Sompo Huguette Mayonde who have urged me to persevere and never give up. To my brothers Makaya Daddy Mayonde and Tshibwidi Chris Musumba for encouraging me and challenging me to always do better. I LOVE you guys. You will always occupy a special place in my heart. iii ACKNOWLEDGEMENTS I would like to acknowledge the financial support by the Department of Trade and Industries (DTI) and National Research Foundation (NRF) “THRIP” awards to Isabel Weiersbye and Edward Witkowski (University of Witwatersrand, Johannesburg) for research with AngloGold Ashanti SA Region Ltd and Ashanti Goldfields Kilo. I am grateful to my supervisors Prof. Glynis Goodman-Cron and Prof. Marcus J. Byrne for their valuable time, guidance, patience, for trusting and encouraging me to pursue independent investigations. To Prof. Marcus J Byrne, thank you for your invaluable advice, mentorship and making me believe that I could do “science”. I owe a huge debt of gratitude to my collaborator and friend Dr J.F. Gaskin for allowing me to work in his laboratory at the USDA Agriculture Service, Sidney, Montana, USA and to his family for welcoming me into their home. I would like to thank Ms Kimberly Mann from the Molecular Ecology laboratory at the USDA in Sidney for her assistance in developing the AFLP markers and conducting the work in a predictable amount of time. Many thanks to Dr Kelsey Glennon for her valuable contribution and advice on the population structure analysis using AFLP data. I would like to extend my special Thanks to Dr. Jenny Botha, Hayden Wilson, Miranda Muller and Lutendo Mugwedi for their field assistance. I would like to pay tribute to the all the AP&ES staff members for welcoming me and working with me throughout my Master’s program and to all the staff of the C.E. Moss Herbarium, especially Dr Renée Reddy, for their assistance and support. Special thanks to my friends and colleagues, Pumeza Cingo, Else Uys, Solomon Newete, McDonald Wanenge, Kendall Hauptfleisch, Archibold Sasa, Seyram Agbemenya, Jubilee Bubala for their priceless words of encouragement, and to Naweji Katembo who is not only a colleague but a brother. Many thanks to Nobukhosi Ngwenya for being my companion and source of joy, your love and kindness will always be appreciated. Finally, I would like to give a big THANKS to GOD for the gift of life, for his protection throughout my master’s program, I thank God for being there during difficult moments and for restoring my health and my mobility after suffering from a stroke in December 2011. To him be the Glory. Special Thanks to Rev. Faith Whitbye of the Kensington Methodist Church for the spiritual support. iv TABLE OF CONTENTS DECLARATION ............................................................................................................................ i ABSTRACT .................................................................................................................................. ii DEDICATION ............................................................................................................................. iii ACKNOWLEDGEMENTS ......................................................................................................... iv LIST OF FIGURES ................................................................................................................... viii LIST OF TABLES ......................................................................................................................... x CHAPTER ONE: INTRODUCTION.......................................................................................... 1 I. LITERATURE REVIEW ..................................................................................................... 2 1.1. TAXONOMY, ORIGIN AND DISTRIBUTION OF TAMARIX ............................... 2 1.2. THE BIOLOGY AND ECOLOGY OF TAMARIX..................................................... 3 1.2.1. Reproduction and seedling establishment ................................................................. 3 1.2.2. Root growth and function .......................................................................................... 4 1.2.3. Soil type, salinity and water use ................................................................................ 4 1.3. TAMARIX IN SOUTH AFRICA ................................................................................. 5 1.4. CLASSIFICATION AND DESCRIPTIONS OF THE TAMARIX SPECIES PRESENT IN SOUTH AFRICA ............................................................................................. 7 1.4.1. Tamarix usneoides ..................................................................................................... 7 1.4.2. Tamarix ramosissima ................................................................................................. 9 1.4.3. Tamarix chinensis ...................................................................................................... 9 1.5. CONTROL OF INVASIVE TAMARIX .................................................................... 11 1.6. IMPACTS OF TAMARIX .......................................................................................... 11 1.6.1. Flooding and erosion ............................................................................................... 12 1.6.2. Animal and plant diversity ...................................................................................... 13 1.7. BIOLOGICAL INVASION AND ALIEN INVASIVE TAMARIX .......................... 13 1.7.1. Classical biological control of alien invasive plant species .................................... 14 1.7.2. Hybridization as a driving force of invasion biology .............................................. 15 1.8. IDENTIFICATION OF TAMARIX ..........................................................................