Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations 1983 Comparison of seed and ovule development in representative taxa of the tribe Cercideae (Caesalpinioideae, Leguminosae) Seanna Reilly Rugenstein Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/rtd Part of the Botany Commons Recommended Citation Rugenstein, Seanna Reilly, "Comparison of seed and ovule development in representative taxa of the tribe Cercideae (Caesalpinioideae, Leguminosae) " (1983). Retrospective Theses and Dissertations. 8435. https://lib.dr.iastate.edu/rtd/8435 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. 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These prints are available upon request from the Dissertations Customer Services Department. 5. Some pages in any document may have indistinct print. In all cases the best available copy has been filmed. University Microfilms International 300N.Zeeb Road Ann Arbor, Ml 48106 8323316 Rugenstein, Seanna Reilly COMPARISON OF SEED AND OVULE DEVELOPMENT IN REPRESENTATIVE TAXA OF THE TRIBE CERCIDEAE (GAESALPINIOIDEAE, LEGUMINOSAE) Iowa State University PH.D. 1983 University Microfilms Intornstionsl 300 N. Zeeb Road, Ann Arbor, Ml 48106 PLEASE NOTE: In all cases this material has been filmed in the best possible way from the available copy. Problems encountered with this document have been identified here with a check mark V . 1. Glossy photographs or pages 2. Colored illustrations, paper or print 3. Photographs with dark background 4. Illustrations are poor copy 5. Pages with black marks, not original copy 6. Print shows through as there is text on both sides of page 7. 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For the Major Department Signature was redacted for privacy. For the Graduate College Iowa State University Ames, Iowa 1983 il TABLE Œ CONTENTS Page INTRODUCTION 1 LITERATURE REVIEW 4 Legume Ovules 5 Reproductive Biology 3^4- Mature Legume Seed 48 MATERIALS AND METHODS 98 Scanning Electron Microscopy 99 Light Microscopy 100 OBSERVATIONS AND DISCUSSION 102 Cercideae Ovule 103 Reproductive Biology 125 Cercideae Seed 128 SUMMARY AND CONCLUSIONS 172 Cercideae Ovule 172 Reproductive Biology 174 Cercideae Seed 175 LITERATURE CITED 179 ACKNOWLEDGMENTS 204 APPENDIX: PLATES 205 Cercideae Ovule 207 Reproductive Biology 223 Cercideae Seed 227 1 INTRODUCTION The Legumlnosae contains three subfamilies, Mimosoideae, Papilionoideae, and Caesalpinioideae, each of which is further divided into tribes. Cercideae, one of five tribes (Polhill and Raven, I98I) belonging to the Caesalpinioideae, is further subdivided into two subtribes, Cercidinae and Bauhiniinae. The subtribe Cercidinae is composed of three genera. One of these, Cereis, contains six species. Cere is is presumed to be an ancient genus and is the only one in the Cercideae with a distribution in the temperate regions of the northern hemisphere. The other two genera of Cercidinae, Griffonia and Menolobus, are African in distribution. The four species of Griffonia are native to tropical west Africa. Adenolobus, with two species, is native to southwest Africa. The subtribe Bauhiniinae is also composed of three genera. Two of these, Brenierea and Barklya, contain only a few species of limited distribution. In contrast, the third genus, Bauhinia sensu lato, consists of about 225 species with a pantropical distribution. Seeds of Cercideae are, in some ways, unique within the Leguminosae. An unusual placement of the micropyle, directly between the hilum and the lens (the micropylar lens), sets the tribe Cercideae apart from all other legumes. By close scrutiny of the seeds of this tribe, I propose to determine whether this "micropylar lens" is a 2 true lens, in the classical sense. If so, then comparable with the lens of the other legumes, its position on the seed would be a true anomaly. Gercideae seeds usually lack the hour-glass osteosclerid layer reported to be an invariable characteristic of legume seeds (Pitot, 1933). They also have a parenchymatous bridge of tissue extending from the funiculus through the outer seed testa and terminating in the hypodermal layers of the seed coat (Wunderlin et al., I98I). An understanding of the mature seed anatomy requires a study of the base upon which the seed is built, namely, the ovule and, later, the embryo. Thus, "...if one could deduce ontogeny from a knowledge of the mature structure, developmental studies would not be needed. Such deductions are not necessarily possible. Even the same or very similar structures may sometimes develop differently." (Sattler, 1974). In Gercideae, Gereis canadensis megasporogenesis (Rembert, 1969a) and G^. siliquastrum early embryo development (Guignard, 1881a; Goursat, 1963) have both been studied. The processes of megasporogenesis, megagametogenesis, and embryo development in Bauhinia have not been reported. Thus, within the constraints of available material, I propose to study comparative development of ovule, seed and embryo in those genera of Gercideae which have not yet been examined. Such a study would be exceedingly useful in the interpretation of the unusual features that exist in the mature seeds of Gercideae. 3 The major portion of the research, however, is the investigation of the mature seed anatomy of Bauhinia and Gereis. The few previous studies of seeds in Gercideae have concerned the seed characteristics of a single species or a small group of species. A more comprehensive survey of seeds in the Gercideae, as here presented, will provide a solid basis for construction of a concept of a generalized Gercideae seed. Ghanges in the organization of the integuments and nucellus will be stressed here rather than the development of the embryo itself. As the various components of the seed coat differentiate, changes in the embryo are examined only as they appear to affect the structure of the seed coat. 4 LITERATURE REVIEW One may consider the period from ovule initiation to mature ovule to be a single developmental sequence that culminates in the maturation of a small megagametophyte in the central region of the ovule. Following fertilization, the ovule and enclosed zygote begin a second sequence of development that culminates in a mature seed containing an embryo surrounded by variable amounts of endosperm and parental sporophyte tissue in the form of the seed coat or testa. This literature review is divided into two main sections. The first pertains to the legume ovule and the second to the legume seed. A review of the literature dealing with legume ovule development, especially in the caesalpinioids,