Reproductive Biology and Floral Phenology of Sicyos Deppei G. Don (Cucurbitaceae) in Disturbed Areas in the City of San Andres Cholula, Puebla, Mexico. by Sandra Villa-Rodriguez A Thesis presented to The University of Guelph In partial fulfilment of requirements for the degree of Master of Science in Environmental Sciences Guelph, Ontario, Canada © Sandra Villa-Rodríguez, December, 2012 ABSTRACT REPRODUCTIVE BIOLOGY AND FLORAL PHENOLOGY OF SICYOS DEPPEI G. DON (CUCURBITACEAE) IN DISTURBED AREAS IN THE CITY OF SAN ANDRES CHOLULA, PUEBLA, MEXICO. Sandra Villa Rodriguez Advisor: University of Guelph, 2012 Professor Peter G. Kevan Sicyos deppei G. Don (Cucurbitaceae) is an invasive monoic annual tendril-bearing vine; it is endemic to Mexico, adapted to the rainfall cycle (June through the end of September) and produces spiny, single seeded fruits. Under serious infestation conditions, S. deppei grows extensively, covering native plants, crops and tree trunks. This study determined the breeding system and pollinators of S. deppei growing in three study sites at urban gardens and disturbed sites at the Campus of the Universidad de las Américas, Puebla in the city of San Andrés Cholula, Puebla (Mexico). Each female inflorescence had an average of 17 flowers at the three study sites. As a step prior to experiments, the timing for stigma receptiveness and pollen viability was determined with the Peroxtesmo KO test (PKO) and Diaminobenzidine test (DAB), respectively. Stigmas of female flowers reach maximum receptivity when flowers are at anthesis; receptivity decreases as the flower reaches the succeeding floral stages. Viability of pollen grains increases with flower development; viability percentages at early stages of floral development are very low, as opposed to the higher percentages of pollen viability found in flowers at anthesis and following developmental stages. Breeding systems were tested for xenogamy and geitonogamy by hand pollinating female flowers. Breeding systems results demonstrated that S. deppei has a mixed-mating system, being able to set fruit and seed when pollinated with pollen from different plants and from pollen of the same plants. The pollinators were determined with the single-visit method. The diversity of floral visitors in this study was low; the most effective pollinator for S. deppei in this study was Apis mellifera. Throughout the rainy season, this study also described the phenology of S. deppei at the plant and flower level, as well as total plant length. Each stage of development in male and female flowers lasts one day. At the end of the rainy season (November, 2010) individual plants measured between 947 and 270 cm. ACKNOWLEDGEMENTS I want to express my deepest gratitude to my advisory committee, who taught me different things, directly and indirectly. All that I have learnt will certainly be useful in my future. I thank Dr. Peter G. Kevan, for whom I feel great respect and admiration. Peter has been a great mentor and an important influence in my life, offering me something to learn each time, not only about Pollination Biology, but also about life itself. Dr. Les Shipp has always been supportive and provided really useful mentoring advice and moral support during his trip to Mexico. I thank Dr. Cory Sheffiled for all his advice on editing and improving my thesis; his questions and suggestions were extremely helpful during this process. Thanks to Dr. Carlos Vergara-Briceño for his assistance on the arrangement for using the study sites and laboratories at the Campus of Universidad de las Américas, Puebla (UDLA-P); I thank him as well for suggesting this project as my thesis topic. I want to thank Dr. Daniel Martínez-Carrera for allowing me to take a very instructive statistics course at Colegio de Postgraduados (COLPOS). From this institution I also want to thank Dr. Mario Tornero-Campante, an exceptional statistics teacher who advised me on my experimental design and reviewed my work as I was making it. Dr. Mario Martínez-Menes was an invaluable help for my statistical analysis and made sure every data obtained during my experiments became useful; his unconditional support has been with me before I can even remember. Dr. Mateo Vargas-Hernández helped me select proper ways to analyze my data; he was available whenever I had questions on statistics. I am grateful to Marianna Horn and Andrew Morse for providing me of an enjoyable environment at the lab. Thanks to Andrea McGraw-Alcock, Sarah Bates and Cara Dawson for always being really amiable and helpful with forms and documents, and for giving me heads-up as to how and when I could reach Peter. I thank my funding sources, including The Consejo Nacional de Ciencia y Tecnología (CONACyT) scholarship, the Natural Sciences and Engineering Research Council of iii Canada, and the Canadian Pollination Initiatitive (NSERC-CANPOLIN). Finally, I want to thank my family. To my Mom and Dad (Mamá y Papá) who are the perfect combination between non-stop pushing parents and providers of a safe environment were we can rest and recharge to keep going. To my brother and sister, Man and Elizabeth: I wouldn’t be anywhere near where I am without both of you; my life is as great as it is in much part thanks to you. To Julio and Satomi, my brother and sister from the heart, who have contributed in magnificent ways to make our family an infinitely more amusing and interesting group: there would be no “Rayo de Sol” without you. Many thanks to Tío Sol and Tía Jo, who have taught me the importance of curiosity, strength of spirit, will to live and respect for whatever may be difficult to understand at first. And dessert for last: I thank Mauricio, my dear husband. You have supported me in ways I never thought were possible. You have always encouraged me to fly, even though some times flying meant for us to be temporarily apart from each other. And mostly, I profoundly thank you for giving me the greatest blessing of my life: our son Manuel, my life’s catalyzer. iv Table of Contents Abstract .........................................................................................................................ii Acknowledgements.......................................................................................................iii Table of Contents..........................................................................................................v List of Figures ...............................................................................................................x List of Tables ........................................................................................................... xviii Chapter I: General introduction and literature review ............................................1 1.1 The Order Cucurbitales .............................................................................................1 1.2 The Family Cucurbitaceae .........................................................................................2 Phylogeny, Diversity and Distribution ..................................................................2 Economic importance of Cucurbitaceae ..................................................................3 Sexual systems of the Cucurbitaceae ......................................................................5 Pollination and the melittophily syndrome .............................................................6 1.3 The Genus Sicyos ......................................................................................................8 Phylogeny, Diversity and Distribution ..................................................................8 Seed dormancy and heteroblastism .......................................................................11 Allelopathic potential ..........................................................................................13 Control by herbicides and conventional practices .................................................15 1.4 Hypothesis and Objectives .....................................................................................17 1.5 Importance of the study ..........................................................................................17 1.6 References ...............................................................................................................18 Chapter II: Study sites for populations of Sicyos deppei ..........................................24 2.1 Location and description of study sites ...................................................................24 2.2 Number of units per female inflorescences of Sicyos deppei at the three study sites ..............................................................................................................................28 2.3 References ...............................................................................................................29 v Chapter III: Phenology and developmental stages of Sicyos deppei .........................30 Abstract ........................................................................................................................30 3.2 Introduction ............................................................................................................31 3.3 Materials and Methods ...........................................................................................33 Emergence of plants and measure of Sicyos deppei individuals ..............................34 Female inflorescences of Sicyos deppei .................................................................35