Submitted by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2017-07-25T12:39:21Z No. of bitstreams: 2 Dissertação - Andressa C. Giacomim.pdf: 1559562 bytes, checksum: af769bddcbc8baed7d61dd096d59e82a (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2017-07-25T12:39:36Z (GMT) No. of bitstreams: 2 Dissertação - Andressa C. Giacomim.pdf: 1559562 bytes, checksum: af769bddcbc8baed7d61dd096d59e82a (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2017-07-25T12:40:32Z (GMT) No. of bitstreams: 2 Dissertação - Andressa C. Giacomim.pdf: 1559562 bytes, checksum: af769bddcbc8baed7d61dd096d59e82a (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-07-25T12:40:32Z (GMT). No. of bitstreams: 2 Dissertação - Andressa C. Giacomim.pdf: 1559562 bytes, checksum: af769bddcbc8baed7d61dd096d59e82a (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2015-03-30 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Isertia is a peculiar genus of Rubiaceae due to its association with secondary tropical forests and recovering forests. It is represented by fifteen species distributed mainly in the rainforests of Central and South America. The morphological peculiarities and the inaccurate use of terminology and typology of Isertia hypoleuca Benth. fruits tends to hinder their classification. Thereby, morphological and anatomical aspects of pericarp and seeds of I. hypoleuca were studied in order to establish the main ontogenetics stages of fruit development, leading to the correct interpretation of its typology. Four stages were registered which main characteristics of each of them are associated with endocarp and exotesta sclerification and seed tissues development. Isertia hypoleuca shows inferior ovary, sincarpic with four to six multi-locular ovary, axial placentation with hemianatrop ovum inserted all along the septum extension. The stage 1 is represented with a newly formed fruit within 1 to 20 days, the exocarp shows maroon coloring, the mesocarp is consistent and the endocarp is undifferentiated. The uniseried mesocarp cell wall shows papilous cells and polyhedral glands. The mesocarp is parenquimatic with many drusen and idioblasts. The endocarp contains about five cell layers in intense process of anticlinal division. The seed is unitegumented and there is intense meristematic activity in the mesotesta. At this stage, the moisture content is the highest, 86.92%. In stage II, the fruit has 77-97 days, exocarp colloring is yellowish green, cored and the exotesta starts the sclerification process. Stage III, fruit with 90 to 210 days, is marked by a sharp sclerification of the endocarp and seed coat, due to the development of endotesta. The endosperm and embryo are well developed. At this stage the fruit has the largest size. In stage IV the fruit is ripe, with 230-250 days, the odor is very similar to the acaí and the color is the deep violet. A reduction of the fruit size occurs showing 9.56 x 8.80 mm, and also the lowest moisture content 31.9% is observed. The exocarp is formed by pericarp wall and underlying mesocarp cells. The mesocarp region corresponding to the fleshy pulp mass comprise a completely or partially disintegrated cells, idioblasts and fibers. The endocarp is osseous and forms four to six pyrenes polispermes disconnected between each other. The seeds are reddish brown angular, with 1 mm, showing a thick testa with foveolad aspect, the endosperm is fleshy. The embryo is white, cylindrical and opaque and occupies the central area of the seed. Based on morphogenesis, the fruit of I. hypoleuca was classified as drupe. / Isertia é um gênero peculiar de Rubiaceae por estar associado às florestas tropicais secundárias ou em processo de regeneração, representado por quinze espécies distribuídas principalmente nas florestas tropicais da América Central e do Sul. O fruto de Isertia hypoleuca Benth. apresenta peculiaridades morfológicas que somadas ao emprego impreciso da terminologia e tipologia de frutos dificultam sua classificação. Dessa forma, foram estudados aspectos morfológicos e anatômicos do pericarpo e semente de I. hypoleuca para estabelecer os principais estádios ontogenéticos do desenvolvimento do fruto e possibilitar a interpretação correta de sua tipologia. Foram registrados quatro estádios, cujas principais características que marcam cada estádio estão associadas ao processo de esclerificação do endocarpo e exotesta e ao desenvolvimento dos demais tecidos da semente. Isertia hypoleuca possui ovário ínfero, sincárpico com quatro a seis lóculos multiovulados, a placentação é axial com óvulos hemianátropos inseridos em toda a extensão do septo. O estádio I é representado pelo fruto recém-formado com um a 20 dias, o exocarpo tem coloração grená o mesocarpo é consistente, o endocarpo é indiferenciado. A parede do pericarpo é unisseriada com células papilosas e glândulas poliédricas. O mesocarpo é parenquimático com muitas drusas e idioblastos. O endocarpo contém cerca de cinco camadas celulares em intenso processo de divisão anticlinal. A semente é unitegumentada e ocorre intensa atividade meristemática na mesotesta. Neste estádio, o teor de umidade é o mais elevado, 86.92%. No estádio II, o fruto tem de 77 a 97 dias, a coloração do exocarpo é verde amarelado, o endocarpo e exotesta iniciam o processo de esclerificação. O estádio III, fruto com 90 a 210 dias, é marcado pela acentuada esclerificação do endocarpo e testa da semente, pela formação da endotesta. O endosperma e embrião estão bem desenvolvidos. Neste estádio o fruto apresenta o maior tamanho. No estádio IV o fruto está maduro, com 230 a 250 dias, o odor é muito semelhante ao do açaí e a coloração é violeta intenso. O fruto sofre redução de seu tamanho, 9.56 x 8.80 mm, e também apresenta o menor teor de umidade 31.9%. O exocarpo é formado por células epidérmicas e células subjacentes do mesocarpo. A região do mesocarpo que corresponde à polpa é uma massa carnosa de células total ou parcialmente desintegradas, idioblastos e fibras. O endocarpo é ósseo, e forma de quatro a seis pirênios polispermos livres entre si. As sementes são marrom avermelhado, angulares, com 1 mm, apresentam testa enrijecida de aspecto foveolado, o endosperma é carnoso. O embrião é cilíndrico branco e opaco e ocupa a região central da semente. Com base na morfogênese, o fruto de I. hypoleuca foi classificado como drupa.

<p>Studies of hybrid zones offer important insights into the process of speciation. Much of the knowledge to be gained is dependent on an accurate estimation of the strength of pre- and post-zygotic isolation between hybridizing taxa. My results demonstrate that hybridization can variously affect different components of fitness. In Ficedula flycatchers, late-breeding females may directly benefit from pairing with a heterospecific male by gaining access to superior territories. The hybrid offspring possess an immune system that is as equally well functioning as in the parental species (the collared, F. albicollis, and pied flycatcher, F. hypoleuca). However, I found that a severe reduction in fertility persists for at least three generations after the actual hybridization event. Combining all information about the reproductive success of hybridizing individuals and their descendents revealed that postzygotic isolation between flycatchers is very strong; hybridizing individuals leave almost no descendents. This thesis presents one of few comprehensive summaries of the selection for/against assortative mating in a natural hybrid zone. These findings suggest a central role for intrinsic postzygotic isolation as a reproductive barrier separating newly evolved bird species, and contrast previous suggestions that postmating isolation is the slowest of the reproductive barriers to evolve in birds.</p><p>Despite this strong selection against hybridization, pre-mating isolation is incomplete. Hybridization often results from females lacking conspecific partners, but appears to be also caused by errors in species recognition. Much of this error probably reflects the short period of time that pied flycatchers on Gotland and Öland have been in sympatry. Compared to collared flycatchers, pied flycatchers are poorer able to discriminate between conspecific and heterospecific song, and male pied flycatchers more often falsely signal their own identity through heterospecific song copying. However, despite colonising the study site from other sympatric populations and having very little gene flow from allopatry, collared flycatchers also possess traits (e.g. delayed plumage maturation) that increase their hybridization risk. Once pre-mating isolation is strong, the rarity of hybridization probably inhibits further selection against traits promoting interspecific mating, especially when such traits may be beneficial in other contexts. This thesis highlights complex interactions between factors affecting hybridization rate that would not be detected if such a study were not field-based. Furthermore, it showcases likely examples in nature of a number of theoretical objections to the evolution of pre-mating barriers between populations living in sympatry.</p>

Studies of hybrid zones offer important insights into the process of speciation. Much of the knowledge to be gained is dependent on an accurate estimation of the strength of pre- and post-zygotic isolation between hybridizing taxa. My results demonstrate that hybridization can variously affect different components of fitness. In Ficedula flycatchers, late-breeding females may directly benefit from pairing with a heterospecific male by gaining access to superior territories. The hybrid offspring possess an immune system that is as equally well functioning as in the parental species (the collared, F. albicollis, and pied flycatcher, F. hypoleuca). However, I found that a severe reduction in fertility persists for at least three generations after the actual hybridization event. Combining all information about the reproductive success of hybridizing individuals and their descendents revealed that postzygotic isolation between flycatchers is very strong; hybridizing individuals leave almost no descendents. This thesis presents one of few comprehensive summaries of the selection for/against assortative mating in a natural hybrid zone. These findings suggest a central role for intrinsic postzygotic isolation as a reproductive barrier separating newly evolved bird species, and contrast previous suggestions that postmating isolation is the slowest of the reproductive barriers to evolve in birds. Despite this strong selection against hybridization, pre-mating isolation is incomplete. Hybridization often results from females lacking conspecific partners, but appears to be also caused by errors in species recognition. Much of this error probably reflects the short period of time that pied flycatchers on Gotland and Öland have been in sympatry. Compared to collared flycatchers, pied flycatchers are poorer able to discriminate between conspecific and heterospecific song, and male pied flycatchers more often falsely signal their own identity through heterospecific song copying. However, despite colonising the study site from other sympatric populations and having very little gene flow from allopatry, collared flycatchers also possess traits (e.g. delayed plumage maturation) that increase their hybridization risk. Once pre-mating isolation is strong, the rarity of hybridization probably inhibits further selection against traits promoting interspecific mating, especially when such traits may be beneficial in other contexts. This thesis highlights complex interactions between factors affecting hybridization rate that would not be detected if such a study were not field-based. Furthermore, it showcases likely examples in nature of a number of theoretical objections to the evolution of pre-mating barriers between populations living in sympatry.