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NOTE TO USERS This reproduction is the best copy available. ONTOGENETIC EVOLUTION AND SPEClATlON IN MIMULUS CARDINALIS AND M. LEWlSll (LAMIALES) A Thesis Presented to The Faculty of Graduate Studies of The University of Guelph by THOMAS HAZLE In partial fulfilment of requirements for the degree of Master of Science May, 2001 O ~hornasHazle, 2001 National Library Bibliothèque nationale 1*1 of Canada du Canada Acquisitions and Acquisitions et Bibliographie Services services bibliographiques 395 Wellington Street 395. rue Wellington Ottawa ON K1A ON4 Ottawa ON KIA ON4 Canada Canada The author has granted a non- L'auteur a accordé une licence non exclusive licence allowing the exclusive permettant a la National Library of Canada to Bîbliothèque nationale du Canada de reproduce, loan, distribute or seil reproduire, prêter, distribuer ou copies of this thesis in microform, vendre des copies de cette thèse sous paper or electronic formats. la forme de microfichelfilm, de reproduction sur papier ou sur format électronique. The author retains ownership of the L'auteur conserve la propriété du copyright in this thesis. Neither the droit d'auteur qui protège cette these. thesis nor substantial extracts f?om it Ni Ia thèse ni des extraits substantiels may be printed or othekse de celle-ci ne doivent être imprimés reproduced without the author's ou autrement reproduits sans son permission. autorisation. ONTOGENETIC EVOLUTION AND SPECIATION IN MIMULUS CARDINALE AND M. LEWlSll (LAMIALES) Thomas Hazle Advisor: University of Guelph, 2001 Professor J.M. Canne-Hilliker The floral ontogenies of three populations of M cardinalis were compared, as were the floral ontogenies of both races of M. lewisii. This was done to compare the Roral ontogenies of each species as exemplified by populations from Yosemite National Park, CA, and interpret differences as evolutionary transformations that occurred during speciation of M. lewisii from an M cardinalis - like ancestor. Between the species, differences in corolla shape were observed shortiy after corolla tube formation. Corollas in buds of M lewisii became dorso - ventrally narrow while those in buds of cardinalis became Iaterally narrow. The shorter stamens and style in flowers of M lewisii were the result of early terminations of growth relative to the growth of those in flowers of -M. cardinalis. The changes in ontogeny that had the largest impact on floral form are hypothesized to have occurred at late stages, while a series of srnaller changes occurred throughout development. I Acknowledgernents No body of work is ever solely the product of one person. This thesis, like most, has had the benefit of valuable intellectual, emotional, technical and inspirational input from rnany people. I would like to express my sincere gratitude to some of these people who have been invaluable throughout the course of this study. Primarily, I would like to thank my supervisor Judy Hilliker. She unquestioningly put her faith in me from the very beginning. If her faith ever faltered, she did not let it show. She has tnily been a source of inspiration as a scholar, a scientist, and as a teacher. Next, I would like to thank my advisory cornmittee, Drs. Brian Husband, Usher Posluszny and Peter Kevan. Each, in his own way, has contributed to this work as well as to my developrnent as a scientist. I would also like to thank Dr. Richard Reader who gave so freely his time and wisdom. I want to thank Dr. Sandy Smith for training me in the deadly art of scanning electron microscopy, and for teaching me how to build a SEM using swiule sticks and a gum wrapper. Many thanks to Paul Beardsley and Dr. Richard Olmstead for seeds and for lending their expertise on the phylogenetic relationships within Mimulus. Also, my gratitude goes to Drs. Doug Schemske and Robert K. Vickery Jr. for seeds. Next, I would like to thank the members of my lab, Lara Yacob and lana Niklova, for lending expertise on (somewhat) related organisms. Also, thanks to Leigh Anne Swayne for her exemplary work as a research assistant. .- II Finally, 1 would like to thank Tracy Burton for her love and support, and for not saying "1 told you son (too many times, at least). I gratefully acknowledge the contributions of the aforementioned people. However, al1 mistakes are mine. iii TABLE OF CONTENTS Main lntroduction Development and organismal diversification Heterochrony Allornetry Additional ontogenetic hypotheses Ontogenetic basis of breeding mating systerns Floral morphology and pollination in Mimulus Significance of research Objectives Materials and Methods The study organisms Microscopy Meiosis Al lornetric analyses Sample sizes Chapter one - floral ontogeny of Mimulus cardinalis lntroduction Results Discussion Figures and tables Chapter two - floral ontogeny of Mimulus lewisii lntroduction Results Discussion Figures and tables Chapter three - ontogenetic evolution of & cardinalis and M. lewisii: morphology, allometry and heterochrony Introduction Results Discussion Figures and tables Main Discussion References v LIST OF TABLES Chapter one Table 1 Slopes and Regression Coefficients of Linear Regression Lines of Bud Length versus Time Table 2 Floral Organ Lengths at Anthesis Table 3 Slopes and Regression Coefficients of Linear Regression Lines of Seiected Allometric Relationships Arnong Populations Table 4 Slopes and Regression Coefficients of Linear Regression Lines of Selected Allometric Relationship Within a FIower Chapter two Table 1 Slopes and Regression Coefficients of Linear Regression Lines of Bud Length versus Time Table 2 Floral Organ Lengths at Anthesis Table 3 Slopes and Regression Coefficients of Linear Regression Lines of Selected Allornetric Relationships Among Populations Table 4 Slopes and Regression Coefficients of Linear Regression Lines of Selected Allometric Relationship Within a Flower Chapter 3 Table 1 Slopes and Regression Coefficients of Linear 330 Regression Lines of Bud Length versus Time Table 2 Floral Organ Lengths at Anthesis 33 1 Table 3 Slopes and Regression Coefficients of 332 Regression of Log Transformed Adaxial and Abaxial Corolla Lengths vs. Time vii LIST OF FIGURES Chapter one Fig. 1 Lateral views of flowers of !& cardinalis. Fig. 2 Longitudinal section of a Rower of & cardinalis. Fig. 3 Inflorescence apices and floral apices of cardinalis. Fig. 4 Early floral apex development of M; cardinalis. Fig. 5 Early floral development of && cardinalis. Fig. 6 Floral apices of M cardinalis. Fig. 7 Floral apices of M; cardinalis. Fig. 8 Buds of @ cardinalis. Fig. 9 Dissected buds of M cardinalis. Fig.1O Buds of M cardinalis. Fig.11 Buds of M cardinalis. Fig.12 Buds of M cardinalis. Fig. 13 Pistils of cardinalis. Fig.14 Buds of !&. cardinalis at sirnilar stages of development Fig.15 Buds of M cardinalis at similar stages of developrnent Fig.16 Buds of !& cardinalis at sirnilar stages of development Fig.17 Buds of M cardinalis at similar stages of development Fig. 18 Corollas of M. cardinalis just prior to anthesis. Fig.19 Transverse sections of flowers of cardinalis. Fig. 20 Pistils of M cardinalis, CI (DM). Fig. 21 Line tracings of corolla lobes of cardinalis. viii Fig. 22 Stamen development of cardinalis. Fig. 23 Stamen development of M. cardinalis. Fig. 24 Starnen development of M. cardinalis. Fig. 25 Stamen alignment of cardinalis flowers (anthesis). Fig. 26 Regression lines showing growth rates of buds of M. cardinalis. 108 Fig. 27 Allometric plot of abaxial corolla length versus adaxial 110 corolla length for M. cardinaiis. Fig. 28 Allometric plot of adaxial and abaxial corolla lengths 112 versus abaxial stamen length for YO. Fig. 29 Allometrîc plots of adaxial and abaxial corolla tube lengths 114 versus ovary length for M. cardinalis. Fig. 30 Allornetric plot of adaxial and abaxial corolla tube lengths 116 versus abaxial stamen length for plants of CI. Fig. 31 Allometric plot of abaxial (representative of adaxial) stamen .118 length versus adaxial corolla length for M. cardinalis. Fig. 32 Allometric plot of abaxial and adaxial stamen lengths 120 versus adaxial corolla length in YO. Fig. 33 Allometric plot of style length veraus adaxial corolla length for -M. cardinalis. Chapter two Fig. 1 Flowers of M. lewisii. ix Fig. 2 Longitudinal section of flower of M. lewisii. Fig. 3 Inflorescence apices and floral apices of M. lewisii. Fig. 4 Early floral developrnent of M. lewisii. Fig. 5 Early floral development of M- lewisii. Fig. 6 Early development of floral apices of M. lewisii. Fig. 7 Early development of floral apices of M. lewisii. Fig. 8 Floral buds of M. lewisii. Fig. 9 Floral buds of M. lewisii. Fig. 10 Floral buds of M. lewisii. Fig. 11 Floral buds of M. lewisii. Fig. 12 Dissected buds of M. lewisii. Fig. 13, Buds of M. lewisii with calyx removed. Fig. 14 Buds of ivl. lewisii with calyx removed. Fig. 15 Buds of M- lewisii with calyx removed. Fig. 16 Buds of M. lewisii with caiyx removed. Fig. 17 Longitudinal sections of buds of M. lewisii. Fig. 18 Dissected floral buds of M. lewisii. Fig. 19 Dissected floral buds of M. lewisii. Fig. 20 Dissected floral buds of M. lewisii. Fig. 21 Corollas of M. lewisii. Fig. 22 Corollas of M. lewisii. Fig. 23 Corollas of M. lewisii. Fig. 24 Flowers of M lewisii. X Fig. 25 Dissected floral buds of M. lewisii. Fig. 26 Lateral views of pistils of M. lewisii. Fig. 27 Lateral views of nectaries of M. lewisii. Fig. 28 Line tracings of corolla lobes of M. lewisii. Fig. 29 Buds and fiowers of M. lewisii. Fig. 30 Longitudinal sections of M. lewisii. Fig. 31 Longitudinal sections of buds and flowers of M. lewisii. Fig. 32 Regression of bud length vs. time for M. lewisii. Fig. 33 Allometric plot of abaxial corolla length versus adaxial corolla length for M- lewisii. Fig. 34 Allometric plot of corolla length vs. style length Fig. 35 Allometric plot of adaxial corolla tube length versus abaxial corolla tube length for M.

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