Este trabalho tem por objetivo mostrar a atividade meristemática da endoderme em raízes de cinco espécies de Commelinaceae (Commelina erecta. Floscopa glabrata, Dichorisandra tyrsiflora, Tradescantia spathacea e T. zebrina). Nas cinco espécies foi observado que na raiz as iniciais endodérmicas sofrem diversas divisões periclinais e dão origem às camadas radiadas de células do córtex. Observou-se ainda, que o cessar dessas divisões nem sempre ocorre simultaneamente em todas as células iniciais, pois, quando ocorre a diferenciação, células que sofreram uma última divisão aparecem ao lado de células que não apresentaram essa divisão. A geração de células pela endoderme pode ser verificada através da observação das células subseqüentes à mesma. Estas células subseqüentes estão dispostas em fileiras radiadas, onde é possível observar que existe uma progressão do tamanho celular do menor (adjacente à endoderme) para o maior (mais distante da endoderme). Estas fileiras de células que são resultantes da endoderme foram denominadas de derivadas da endoderme meristemática (DEM). No caule, a atividade meristemática do periciclo e da endoderme é limitada à região nodal. Nesta região ocorre a formação de novas raízes, gemas caulinares e saídas de traços. Nos entrenós, os feixes vasculares são colaterais e a endoderme se apresenta, em geral, como bainha amilífera, podendo apresentar estrias de Caspary; o periciclo encontra-se parenquimático. Na região do nó, observa-se uma intensa atividade do periciclo (ou da região pericíclica) formando feixes vasculares colaterais envoltos por fibras e o plexo periférico em direção às raízes adventícias. Verificou-se também uma pequena atividade da endoderme, produzindo duas a três camadas do córtex interno. No primeiro e no segundo entrenós, a endoderme apresenta-se suberificada e o periciclo parenquimático. Corroborando com estudos recentes e autores do século XIX, o espessamento primário é devido à atividade centrípeta do periciclo e à atividade centrífuga da endoderme. Existem poucos relatos na literatura sobre a presença de endoderme e periciclo nas plantas vasculares. A maioria dos autores consideram os tecidos que envolvem os feixes vasculares das folhas como a bainha do feixe. O objetivo deste trabalho é mostrar que a bainha do feixe da folha é composta de endoderme e periciclo, bem como a continuidade destes tecidos entre o caule e a folha. Há uma perfeita continuidade entre os tecidos do caule e da folha quando se observa o traço indo em direção a folha. Nota-se também, que a endoderme que no caule envolve o cilindro vascular também envolve os feixes das folhas, constituindo assim, os monostelos. Não foi observada a presença de estria de Caspary na folha, foi observado somente o espessamento irregular da endoderme e do periciclo. Por se tratarem de monostelos, decidiu-se aceitar a denominação de unidades vasculares no lugar de feixes, nas folhas. Há poucos relatos na literatura sobre anatomia de plantas parasitadas por agentes minadores, os quais promovem escavações ou caminhos através do consumo dos tecidos internos das plantas por larvas de diversos insetos. A proposta deste trabalho foi analisar anatomicamente a ocorrência de minas foliares em Commelina diffusa e Floscopa glabrata causadas por espécies de larvas endofitófagas de dípteros, pertencentes a duas famílias: Agromyzidae e Chironomidae. Em Commelina diffusa foram encontradas larvas da família Agromyzidae e em Floscopa glabrata observaram três exuvias cefálicas de Chironomidae. Os dados anatômicos revelaram que os minadores consumiram apenas os tecidos parenquimáticos do mesofilo, formando minas lineares. Além disso, notou-se que a epiderme e os tecidos vasculares de porte médio foram mantidos intactos em ambas as espécies, não apresentando alterações estruturais, como a neoformação de tecidos. / The aim of this work is to show the meristematic activity of the endodermis in roots of five species of Commelinaceae (Commelina erecta, Floscopa glabrata, Dichorisandra tyrsiflora, Tradescantia spathacea e T. zebrina). In all species was observed the initial endodermis suffered several periclinal divisions, originating the radiate layers of the cortex cells. In addition, these divisions does not stop simultaneously in all initial cells because, when differentiation occurs, cells that had a last division apears beside cells that have not divide yet. The generation of cells by the endodermis can be verified observing its subsequent cells. These subsequent cells are disposed as rows and in a radiate pattern where is possible to observe a progression in cell size, that is, the cells become greater as the distance from the endodermis increases. These rows of cells are derived from the endodermis and are called derivatives of the meristematic endodermis (DME). In the stem, the meristematic activity of pericycle and endodermis is limited to the nodal region. In this region occurs the formation of new adventitious roots, buds and leaf traces. In the internodes the vascular bundles are collateral, the endodermis usually appears as a starch sheath, which may have Caspary strips, and the pericycle is parenchymatous. In the nodal region, there is intensive activity of pericycle (or pericycle region), promoting the formation of vascular bundles with fibers around it, and the peripheral plexus of adventitious roots. Moreover, there was also little activity of endodermis producing only from two to three layers of inner cortex. The endodermis has suberin. In conclusion, the primary thickening is caused by the centripetal activity of pericycle and the centrifugal activity of the endodermis. In specialized literature, reports on anatomy of presence of the endodermis and the pericycle in leaves of vascular plants are few in number. Most authors consider the tissues that involve the leaves bundles as sheath bundle. The aim of this work was to show the sheath bundle is composed by the endodermis and the pericycle, and investigate the continuity of tissues between stem and leaf in Monocotyledons. The results showed that there is a perfect continuity between the tissues of stem and leaf when the leaf trace is observed going in direction to the leaf. In addition, it was observed that the endodermis of stem involve not only the vascular cylinder but also the leaf bundles, that is, the monosteles. The presence of Caspary strip in the endodermis was not observed. It was decided to name the leaf bundle as unity instead of bundle, as proposed for recently researches. In specialized literature, reports on anatomy of miners in host plants are few in number. These agents trigger excavations, or paths, by consumption of plant inner tissues by larvae of several insects. The aim of this work was to investigate leaf miner occurrence in Commelina diffusa and Floscopa glabrata using anatomical techniques. In this case, it was discovered that members of Agromyzidae and Chironomidae families, which are Diptera endophytophagous larvae types, were responsible for the tunnels. Moreover, in Commelina diffusa was found Agromyzidae larvae while in Floscopa glabrata three Chironomidae cephalic exuviae were found. The miners, as shown by anatomical studies, used only parenchymatic tissues of mesophyll for their feeding, causing the formation of linear miners. In addition, the epidermis and the middle-sized vessel bundles, in both species, were kept intact, showing no structural modification, like neoformation of tissues.

To test the hypothesis that red-osier dogwood cuttings from a more stressful edaphic environment (dry site) would have a greater salinity tolerance compared with cuttings from a less stressful environment (moist site) a greenhouse experiment was designed. Cuttings collected from three sites in southeastern Manitoba varying in edaphic conditions (moisture) were exposed to 0, 25, 50, or 100 mM NaCl in hydroponics. After four weeks of treatment, physiological parameters were measured. No differences in salinity tolerance were observed between the sites; nevertheless, this study supported previous results suggesting that red-osier dogwood can limit the transport of Na+ from the root to the shoot. To determine the presence of barriers to ion movement, the roots of red-osier dogwood exposed to NaCl were sectioned and observed using brightfield and fluorescence techniques. A modified outer cortical layer was observed suggesting the presence of an exodermis, which would be an additional barrier to Na+ and Cl- movement. Furthermore, the maturation of the endodermis and exodermis occurring closer to the root tip could also contribute to limiting the transport of Na+ to the shoot.

To test the hypothesis that red-osier dogwood cuttings from a more stressful edaphic environment (dry site) would have a greater salinity tolerance compared with cuttings from a less stressful environment (moist site) a greenhouse experiment was designed. Cuttings collected from three sites in southeastern Manitoba varying in edaphic conditions (moisture) were exposed to 0, 25, 50, or 100 mM NaCl in hydroponics. After four weeks of treatment, physiological parameters were measured. No differences in salinity tolerance were observed between the sites; nevertheless, this study supported previous results suggesting that red-osier dogwood can limit the transport of Na+ from the root to the shoot. To determine the presence of barriers to ion movement, the roots of red-osier dogwood exposed to NaCl were sectioned and observed using brightfield and fluorescence techniques. A modified outer cortical layer was observed suggesting the presence of an exodermis, which would be an additional barrier to Na+ and Cl- movement. Furthermore, the maturation of the endodermis and exodermis occurring closer to the root tip could also contribute to limiting the transport of Na+ to the shoot.

Este trabalho tem por objetivo mostrar a atividade meristemática da endoderme em raízes de cinco espécies de Commelinaceae (Commelina erecta. Floscopa glabrata, Dichorisandra tyrsiflora, Tradescantia spathacea e T. zebrina). Nas cinco espécies foi observado que na raiz as iniciais endodérmicas sofrem diversas divisões periclinais e dão origem às camadas radiadas de células do córtex. Observou-se ainda, que o cessar dessas divisões nem sempre ocorre simultaneamente em todas as células iniciais, pois, quando ocorre a diferenciação, células que sofreram uma última divisão aparecem ao lado de células que não apresentaram essa divisão. A geração de células pela endoderme pode ser verificada através da observação das células subseqüentes à mesma. Estas células subseqüentes estão dispostas em fileiras radiadas, onde é possível observar que existe uma progressão do tamanho celular do menor (adjacente à endoderme) para o maior (mais distante da endoderme). Estas fileiras de células que são resultantes da endoderme foram denominadas de derivadas da endoderme meristemática (DEM). No caule, a atividade meristemática do periciclo e da endoderme é limitada à região nodal. Nesta região ocorre a formação de novas raízes, gemas caulinares e saídas de traços. Nos entrenós, os feixes vasculares são colaterais e a endoderme se apresenta, em geral, como bainha amilífera, podendo apresentar estrias de Caspary; o periciclo encontra-se parenquimático. Na região do nó, observa-se uma intensa atividade do periciclo (ou da região pericíclica) formando feixes vasculares colaterais envoltos por fibras e o plexo periférico em direção às raízes adventícias. Verificou-se também uma pequena atividade da endoderme, produzindo duas a três camadas do córtex interno. No primeiro e no segundo entrenós, a endoderme apresenta-se suberificada e o periciclo parenquimático. Corroborando com estudos recentes e autores do século XIX, o espessamento primário é devido à atividade centrípeta do periciclo e à atividade centrífuga da endoderme. Existem poucos relatos na literatura sobre a presença de endoderme e periciclo nas plantas vasculares. A maioria dos autores consideram os tecidos que envolvem os feixes vasculares das folhas como a bainha do feixe. O objetivo deste trabalho é mostrar que a bainha do feixe da folha é composta de endoderme e periciclo, bem como a continuidade destes tecidos entre o caule e a folha. Há uma perfeita continuidade entre os tecidos do caule e da folha quando se observa o traço indo em direção a folha. Nota-se também, que a endoderme que no caule envolve o cilindro vascular também envolve os feixes das folhas, constituindo assim, os monostelos. Não foi observada a presença de estria de Caspary na folha, foi observado somente o espessamento irregular da endoderme e do periciclo. Por se tratarem de monostelos, decidiu-se aceitar a denominação de unidades vasculares no lugar de feixes, nas folhas. Há poucos relatos na literatura sobre anatomia de plantas parasitadas por agentes minadores, os quais promovem escavações ou caminhos através do consumo dos tecidos internos das plantas por larvas de diversos insetos. A proposta deste trabalho foi analisar anatomicamente a ocorrência de minas foliares em Commelina diffusa e Floscopa glabrata causadas por espécies de larvas endofitófagas de dípteros, pertencentes a duas famílias: Agromyzidae e Chironomidae. Em Commelina diffusa foram encontradas larvas da família Agromyzidae e em Floscopa glabrata observaram três exuvias cefálicas de Chironomidae. Os dados anatômicos revelaram que os minadores consumiram apenas os tecidos parenquimáticos do mesofilo, formando minas lineares. Além disso, notou-se que a epiderme e os tecidos vasculares de porte médio foram mantidos intactos em ambas as espécies, não apresentando alterações estruturais, como a neoformação de tecidos. / The aim of this work is to show the meristematic activity of the endodermis in roots of five species of Commelinaceae (Commelina erecta, Floscopa glabrata, Dichorisandra tyrsiflora, Tradescantia spathacea e T. zebrina). In all species was observed the initial endodermis suffered several periclinal divisions, originating the radiate layers of the cortex cells. In addition, these divisions does not stop simultaneously in all initial cells because, when differentiation occurs, cells that had a last division apears beside cells that have not divide yet. The generation of cells by the endodermis can be verified observing its subsequent cells. These subsequent cells are disposed as rows and in a radiate pattern where is possible to observe a progression in cell size, that is, the cells become greater as the distance from the endodermis increases. These rows of cells are derived from the endodermis and are called derivatives of the meristematic endodermis (DME). In the stem, the meristematic activity of pericycle and endodermis is limited to the nodal region. In this region occurs the formation of new adventitious roots, buds and leaf traces. In the internodes the vascular bundles are collateral, the endodermis usually appears as a starch sheath, which may have Caspary strips, and the pericycle is parenchymatous. In the nodal region, there is intensive activity of pericycle (or pericycle region), promoting the formation of vascular bundles with fibers around it, and the peripheral plexus of adventitious roots. Moreover, there was also little activity of endodermis producing only from two to three layers of inner cortex. The endodermis has suberin. In conclusion, the primary thickening is caused by the centripetal activity of pericycle and the centrifugal activity of the endodermis. In specialized literature, reports on anatomy of presence of the endodermis and the pericycle in leaves of vascular plants are few in number. Most authors consider the tissues that involve the leaves bundles as sheath bundle. The aim of this work was to show the sheath bundle is composed by the endodermis and the pericycle, and investigate the continuity of tissues between stem and leaf in Monocotyledons. The results showed that there is a perfect continuity between the tissues of stem and leaf when the leaf trace is observed going in direction to the leaf. In addition, it was observed that the endodermis of stem involve not only the vascular cylinder but also the leaf bundles, that is, the monosteles. The presence of Caspary strip in the endodermis was not observed. It was decided to name the leaf bundle as unity instead of bundle, as proposed for recently researches. In specialized literature, reports on anatomy of miners in host plants are few in number. These agents trigger excavations, or paths, by consumption of plant inner tissues by larvae of several insects. The aim of this work was to investigate leaf miner occurrence in Commelina diffusa and Floscopa glabrata using anatomical techniques. In this case, it was discovered that members of Agromyzidae and Chironomidae families, which are Diptera endophytophagous larvae types, were responsible for the tunnels. Moreover, in Commelina diffusa was found Agromyzidae larvae while in Floscopa glabrata three Chironomidae cephalic exuviae were found. The miners, as shown by anatomical studies, used only parenchymatic tissues of mesophyll for their feeding, causing the formation of linear miners. In addition, the epidermis and the middle-sized vessel bundles, in both species, were kept intact, showing no structural modification, like neoformation of tissues.

Essa dissertação foi subdivida em cinco capítulos que, apesar de relacionados entre, podem ser lidos e compreendidos de forma independente. O primeiro capítulo trata de um breve histórico sobre o espessamento primário em caules de monocotiledôneas. Seu principal objetivo é deixar evidente para o leitor a problemática referente tanto à nomenclatura dos tecidos relacionados ao espessamento primário em monocotiledôneas, quanto explicar as hipóteses que embasam essas nomenclaturas. O segundo capítulo teve como principal objetivo evidenciar que, apesar da discordância de muitos autores da atualidade, existe continuidade dos tecidos endoderme e periciclo entre os órgãos no corpo vegetativo de monocotiledôneas, apresentando indícios que apóiam esse pensamento. Já o terceiro capítulo, Caule, demonstra dados que corroboram o pensamento defendido nessa dissertação: endoderme e periciclo são os tecidos responsáveis pelo espessamento do corpo primário do caule de monocotiledôneas. O quarto capítulo, Folha, discute e demonstra a presença de endoderme (entorno da unidade vascular desse órgão) e periciclo (como parte dessa unidade vascular) em folhas de Zingiberaceae e Costaceae. O quinto e último capítulo aborda a importância dos já mencionados tecidos, quais sejam endoderme e periciclo, na formação da raiz primária. / Since ends of 19th century, arised a great diversity of terminologys to name meristematic region responsible for primary thickening in monocotyledons. Despite of this great number of denominations, a few hypothesis and ideas are utilized to base this great complex of terminologys. This historical chapter aims explain the origin from this terminologys and understand correlations between hypothesis basis. At the end of this explanation, you can understand why the defense of presence of endodermal and pericycle tissue as the two meristematic tissues responsible for this primary thickening in monocotyledonous rather than the currently most accepted name of \"PTM\", a single meristem advocated by many authors. Despite of many authors consider fact the continuity between the vascular tissues of stem and leaf and stem and root, few authors consider that the endodermis (between stem and leaf and between stem and root) and pericycle (between stem and leaf and stem and between root) of these organs may be continuous. It was shown, with verification of the continuity of the tissues mentioned above, the plant is a unit and can be found in the root and leaves the same tissues found in the stem, in this case, the main tissues examined in this chapter: endodermis and pericycle. This chapter aims to discuss, demonstrate, and finally prove the continuity of the tissues mentioned in Zingiberaceae, and also describe the morphology of these tissues in each of the aforementioned organs. The stems of monocots has been the subject of studies since the nineteenth century. But despite the large amount of work produced since then, there is still controversy regarding the primary tissue responsible for thickening of this organ. The families Zingiberaceae Costaceae and serve as a model for which more data were collected showing not only the presence of endodermis and pericycle in the stem, but also to show that these are the meristematic tissues responsible for primary thickening in this organ. It was observed in the underground stem, the presence of strips of Caspary in the region farthest from the apex. Already in the air stem, the endodermis was seen only parenchymatous, without any morphological alteration in its walls. The meristematic pericycle was found in the underground stem, but in the aerial stems it is pluriseriated and have cell walls thick. Many authors recognize that the leaf is a projection of stem. But despite this recognition of the origin of this organ, few authors admit that there is continuity between the tissue found in these two organs. This chapter aims to show that tissue found in the stem, which are endodermis and pericycle, are also present in the leaves of species of Zingiberaceae and Costaceae families. Although not possible to observe strips of Caspary involving the vascular unit found in the leaves, could be observed in leaf expansion an accumulation of phenolic substances in tissue, facilitating the visualization of the cells corresponding to the endodermis. The pericycle, forming pericycle fibers was also observed and described. The root is one of the most preserved organs of all vegetative organs of vascular plants. This is the only organ where the tissues endodermis and pericycle are found in any textbook and that are part of primary body of the root. But despite this recognition, the endodermis is not seen by the authors in general, as being important for the formation of the root cortex. This chapter shows the presence of endodermis with meristematic activity, and demonstrate its derivatives (DEMs) in the root cortex of species of families Zingiberacaea and Costaceae.

Essa dissertação foi subdivida em cinco capítulos que, apesar de relacionados entre, podem ser lidos e compreendidos de forma independente. O primeiro capítulo trata de um breve histórico sobre o espessamento primário em caules de monocotiledôneas. Seu principal objetivo é deixar evidente para o leitor a problemática referente tanto à nomenclatura dos tecidos relacionados ao espessamento primário em monocotiledôneas, quanto explicar as hipóteses que embasam essas nomenclaturas. O segundo capítulo teve como principal objetivo evidenciar que, apesar da discordância de muitos autores da atualidade, existe continuidade dos tecidos endoderme e periciclo entre os órgãos no corpo vegetativo de monocotiledôneas, apresentando indícios que apóiam esse pensamento. Já o terceiro capítulo, Caule, demonstra dados que corroboram o pensamento defendido nessa dissertação: endoderme e periciclo são os tecidos responsáveis pelo espessamento do corpo primário do caule de monocotiledôneas. O quarto capítulo, Folha, discute e demonstra a presença de endoderme (entorno da unidade vascular desse órgão) e periciclo (como parte dessa unidade vascular) em folhas de Zingiberaceae e Costaceae. O quinto e último capítulo aborda a importância dos já mencionados tecidos, quais sejam endoderme e periciclo, na formação da raiz primária. / Since ends of 19th century, arised a great diversity of terminologys to name meristematic region responsible for primary thickening in monocotyledons. Despite of this great number of denominations, a few hypothesis and ideas are utilized to base this great complex of terminologys. This historical chapter aims explain the origin from this terminologys and understand correlations between hypothesis basis. At the end of this explanation, you can understand why the defense of presence of endodermal and pericycle tissue as the two meristematic tissues responsible for this primary thickening in monocotyledonous rather than the currently most accepted name of \"PTM\", a single meristem advocated by many authors. Despite of many authors consider fact the continuity between the vascular tissues of stem and leaf and stem and root, few authors consider that the endodermis (between stem and leaf and between stem and root) and pericycle (between stem and leaf and stem and between root) of these organs may be continuous. It was shown, with verification of the continuity of the tissues mentioned above, the plant is a unit and can be found in the root and leaves the same tissues found in the stem, in this case, the main tissues examined in this chapter: endodermis and pericycle. This chapter aims to discuss, demonstrate, and finally prove the continuity of the tissues mentioned in Zingiberaceae, and also describe the morphology of these tissues in each of the aforementioned organs. The stems of monocots has been the subject of studies since the nineteenth century. But despite the large amount of work produced since then, there is still controversy regarding the primary tissue responsible for thickening of this organ. The families Zingiberaceae Costaceae and serve as a model for which more data were collected showing not only the presence of endodermis and pericycle in the stem, but also to show that these are the meristematic tissues responsible for primary thickening in this organ. It was observed in the underground stem, the presence of strips of Caspary in the region farthest from the apex. Already in the air stem, the endodermis was seen only parenchymatous, without any morphological alteration in its walls. The meristematic pericycle was found in the underground stem, but in the aerial stems it is pluriseriated and have cell walls thick. Many authors recognize that the leaf is a projection of stem. But despite this recognition of the origin of this organ, few authors admit that there is continuity between the tissue found in these two organs. This chapter aims to show that tissue found in the stem, which are endodermis and pericycle, are also present in the leaves of species of Zingiberaceae and Costaceae families. Although not possible to observe strips of Caspary involving the vascular unit found in the leaves, could be observed in leaf expansion an accumulation of phenolic substances in tissue, facilitating the visualization of the cells corresponding to the endodermis. The pericycle, forming pericycle fibers was also observed and described. The root is one of the most preserved organs of all vegetative organs of vascular plants. This is the only organ where the tissues endodermis and pericycle are found in any textbook and that are part of primary body of the root. But despite this recognition, the endodermis is not seen by the authors in general, as being important for the formation of the root cortex. This chapter shows the presence of endodermis with meristematic activity, and demonstrate its derivatives (DEMs) in the root cortex of species of families Zingiberacaea and Costaceae.

Complex Exocyst consists of eight proteins and it is known as a Sec6/8. Its composition is evolutionarily highly conserved amongst all the species. This complex is involved in vesicle trafficking as a part of attaching mechanism to a specific place on the plasma membrane. EXO70 subunit has been found in 23 copies in Arabidopsis thaliana genome. In this study we have been examine paraloges EXO70H7 and EXO70H8. There have been suggestions that these genes are important in development of roots according to the previous studies. We have not been able to identify any significant phenotype within the mutant plants in these genes. There has been studied other mutant appearance during the stress experiments. Most of these experiments did not identify any divergence. Only experiments with germination during stress conditions revealed significantly worse germination of exo70H7 mutant seeds on the medium containing sorbitol. This suggests that mutant seeds have a worse protection against osmotic stress. Significantly worse germination of exo70H8 seeds on the medium with excess NaCl indicates that these seeds incriminate to higher absorption of sodium ions. Analysis of the cell localization of GFP constructs brought knowledge of appearance EXO70H7 and EXO70H8 proteins. EXO70H7 locates in the cytoplasm and in...

A síndrome Kranz é um conjunto de características anatômicas, ultra-estruturais e bioquímicas que culminam na realização da fotossíntese C4. Tal síndrome apresenta grande diversidade dentre as Angiospermas, tornando-se conveniente seu estudo em todos os níveis acima citados para a completa caracterização da mesma. No presente trabalho foi investigada a síndrome Kranz de Gomphrena arborescens e G. scapigera (Amaranthaceae) com ênfase na origem ontogenética da bainha Kranz, na descrição ultra-estrutural e na confirmação bioquímica sobre o tipo de fotossíntese C4. O desenvolvimento foliar dessas espécies indica que a bainha Kranz é originada da camada mais interna do mesofilo, a endoderme foliar. Uma discussão sobre os termos presentes na literatura para a descrição dessa bainha, todos eles focados em sua função na fotossíntese C4, demonstra a importância de se utilizar termos que informem a origem ontogenética dessa bainha, como endoderme e periciclo. Na análise ultra-estrutural, foram identificados possíveis fatores que interferem na fotossíntese de ambas as espécies, como o espessamento e a composição da parede da bainha Kranz, o posicionamento centrípeto dos cloroplastos e a presença de retículo periférico nos mesmos. Embora a análise bioquímica tenha resultado em informações ainda não conclusivas, o dimorfismo dos cloroplastos sugere a realização da fotossíntese C4 do tipo NADP-ME. O presente trabalho, de uma forma geral, contribui ao conhecimento da síndrome Kranz dentre as Amaranthaceae s.s., um grupo em que a ultra-estrutura e a bioquímica ainda são pouco conhecidas, e ressalta a importância dos estudos anatômicos, principalmente com enfoque ontogenético, para o melhor conhecimento da diversidade da síndrome Kranz dentre as Angiospermas. / The Kranz syndrome is a set of anatomical, ultrastructural and biochemical features that culminate in the C4 photosynthesis. This syndrome has a huge diversity among Angiosperms, so it became suitable to survey all the levels above cited for its complete characterization. In the present work the Kranz syndrome of Gomphrena arborescens and G. scapigera (Amaranthaceae) is studied, with emphasis on the ontogenetic origin of the Kranz sheath, on the ultrastructural description, and on the biochemical confirmation about the C4 photosynthesis kind. The foliar development of these species shows that the Kranz sheath is originated from the inner layer of the mesophyll, the foliar endodermis. A discussion about the literature terms used to describe the Kranz sheath, all of them referring to the function of this layer in C4 photosynthesis, demonstrates the importance of using terms that inform the ontogenetic origin of this layer, such as endodermis and perycicle. The ultrastructural analysis identified possible factors that interfere on the C4 photosynthesis of both species, such as wall thickening and composition of Kranz sheath cells, the centripetal position of chloroplasts and the peripheral reticulum in chloroplasts. Although biochemical analysis has resulted in no conclusive information, the chloroplast dimorphism suggests the NADP-ME C4 photosynthesis. This work, in a general way, contributes to the knowledge of the Kranz syndrome among Amaranthaceae s.s., a group that has the ultrastructure and the biochemistry of C4 photosynthesis poorly known. It also draws attention to the importance of anatomical surveys concerning the ontogenetic origin of Kranz sheath for a better understanding on the diversity of Kranz syndrome among Angiosperms.

Após o estabelecimento do crescimento axial, promovido pelos meristemas apicais, em monocotiledôneas surge abaixo do meristema apical caulinar, uma região entre o córtex e o cilindro central que promove o crescimento em espessura. Este crescimento é promovido através da adição de tecidos vasculares (centripetamente) e de tecidos parenquimáticos (centrifugamente). Durante muitos anos este espessamento foi denominado e interpretado de diferentes formas, sendo demonstrado como um único meristema denominado de meristema de espessamento primário com atividade bidirecional. Recentemente, pesquisas demonstram que o espessamento primário em caule é promovido pela atividade de dois tecidos, a endoderme e o periciclo, ambos em atividade meristemática. Com o intuito de trazer à tona informações detalhadas sobre estes dois tecidos que compõem esta zona meristemática, assim como o seu funcionamento e origem, o Capítulo I traz informações morfológicas e anatômicas detalhadas do caule de 16 espécies de Tillandsioideae (Bromeliaceae). Os representantes escolhidos para esta análise foram os gêneros Alcantarea, Tillandsia e Vriesea que possuem uma ampla variação morfológica permitindo, assim, comparar entre eles o processo de espessamento do caule. Demostrou-se ser a endoderme e o periciclo os tecidos, que juntos, promovem o espessamento e a manutenção do corpo primário dessas plantas. No entanto, mais evidências que suportem a hipótese que o espessamento primário é realizado por dois tecidos são necessárias. Assim o capítulo II aborda a caracterização do espessamento primário sob a luz da expressão gênica do gene SCARECROW (SCR), gene candidato a ser um marcador da atividade endodérmica, permitindo assim separar e caracterizar molecularmente os tecidos que promovem o espessamento primário. Desta forma, analisou-se a expressão do scr ao longo do desenvolvimento do caule em Zea mays (Poceae), avaliando a possibilidade do gene scr ser um marcador de atividade endodérmica. Com a confirmação, o gene ortólogo ao scr de Vriesea gigantea foi clonado e caracterizado. E finalmente, analisou-se o padrão de expressão de scr em morfotipos diferentes, Vriesea gigantea e Tillandisia usneoides espécies escolhidas durante a análise do capitulo I / After the establishment of axial growth, promoted by apical meristems, in monocots appears below the shoot apical meristem, a region between the cortex and central cylinder that promotes the growth in thickness. This growth is promoted by the addition of vascular tissues (centripetally) and parenchyma tissues (centrifugally). During many years this thickening was called and interpreted in different ways and it has been shown as a single meristem called the primary thickening meristem with bidirectional activity. Recently, researches show that the primary thickening in stem is promoted by the activity of two tissues, the endodermis and pericycle, both in meristematic activity. In order to elicit detailed information about these two tissues that compose this meristematic zone, as well as its operation and origin, Chapter I provides detailed anatomical and morphological information about the stems of 16 species of Tillandsioideae (Bromeliaceae). The representatives chosen for this analysis were the genus: Alcantarea, Tillandsia and Vriesea that have a wide morphological variation, thus allowing to compare between the process of stem thickening. It was demonstrated to be the endodermis and pericycle the tissues that together promote the thickening and maintenance of this primary plant body. However, more evidences supporting the hypothesis that the primary thickening is accomplished by two tissues are required. Thus Chapter II deals with the characterization of the primary thickening in the light of gene expression. The SCARECROW (SCR) gene is good candidate to be a marker of endodermal activity, thereby separating and molecularly characterizing the tissues that promote primary thickening. Therefore, it was analyzed the expression of SCR throughout the development of the stem in Zea mays (Poaceae), evaluating the possibility of SCR gene be a marker of endodermal activity throughout the development of a monocot. With the confirmation, the ortholog of SCR gene of Vriesea gigantean was cloned and characterized. And finally, the expression pattern of SCR was analyzed in Vriesea gigantean and Tillandisia usneoides species chosen during the analysis of Chapter I

Após o estabelecimento do crescimento axial, promovido pelos meristemas apicais, em monocotiledôneas surge abaixo do meristema apical caulinar, uma região entre o córtex e o cilindro central que promove o crescimento em espessura. Este crescimento é promovido através da adição de tecidos vasculares (centripetamente) e de tecidos parenquimáticos (centrifugamente). Durante muitos anos este espessamento foi denominado e interpretado de diferentes formas, sendo demonstrado como um único meristema denominado de meristema de espessamento primário com atividade bidirecional. Recentemente, pesquisas demonstram que o espessamento primário em caule é promovido pela atividade de dois tecidos, a endoderme e o periciclo, ambos em atividade meristemática. Com o intuito de trazer à tona informações detalhadas sobre estes dois tecidos que compõem esta zona meristemática, assim como o seu funcionamento e origem, o Capítulo I traz informações morfológicas e anatômicas detalhadas do caule de 16 espécies de Tillandsioideae (Bromeliaceae). Os representantes escolhidos para esta análise foram os gêneros Alcantarea, Tillandsia e Vriesea que possuem uma ampla variação morfológica permitindo, assim, comparar entre eles o processo de espessamento do caule. Demostrou-se ser a endoderme e o periciclo os tecidos, que juntos, promovem o espessamento e a manutenção do corpo primário dessas plantas. No entanto, mais evidências que suportem a hipótese que o espessamento primário é realizado por dois tecidos são necessárias. Assim o capítulo II aborda a caracterização do espessamento primário sob a luz da expressão gênica do gene SCARECROW (SCR), gene candidato a ser um marcador da atividade endodérmica, permitindo assim separar e caracterizar molecularmente os tecidos que promovem o espessamento primário. Desta forma, analisou-se a expressão do scr ao longo do desenvolvimento do caule em Zea mays (Poceae), avaliando a possibilidade do gene scr ser um marcador de atividade endodérmica. Com a confirmação, o gene ortólogo ao scr de Vriesea gigantea foi clonado e caracterizado. E finalmente, analisou-se o padrão de expressão de scr em morfotipos diferentes, Vriesea gigantea e Tillandisia usneoides espécies escolhidas durante a análise do capitulo I / After the establishment of axial growth, promoted by apical meristems, in monocots appears below the shoot apical meristem, a region between the cortex and central cylinder that promotes the growth in thickness. This growth is promoted by the addition of vascular tissues (centripetally) and parenchyma tissues (centrifugally). During many years this thickening was called and interpreted in different ways and it has been shown as a single meristem called the primary thickening meristem with bidirectional activity. Recently, researches show that the primary thickening in stem is promoted by the activity of two tissues, the endodermis and pericycle, both in meristematic activity. In order to elicit detailed information about these two tissues that compose this meristematic zone, as well as its operation and origin, Chapter I provides detailed anatomical and morphological information about the stems of 16 species of Tillandsioideae (Bromeliaceae). The representatives chosen for this analysis were the genus: Alcantarea, Tillandsia and Vriesea that have a wide morphological variation, thus allowing to compare between the process of stem thickening. It was demonstrated to be the endodermis and pericycle the tissues that together promote the thickening and maintenance of this primary plant body. However, more evidences supporting the hypothesis that the primary thickening is accomplished by two tissues are required. Thus Chapter II deals with the characterization of the primary thickening in the light of gene expression. The SCARECROW (SCR) gene is good candidate to be a marker of endodermal activity, thereby separating and molecularly characterizing the tissues that promote primary thickening. Therefore, it was analyzed the expression of SCR throughout the development of the stem in Zea mays (Poaceae), evaluating the possibility of SCR gene be a marker of endodermal activity throughout the development of a monocot. With the confirmation, the ortholog of SCR gene of Vriesea gigantean was cloned and characterized. And finally, the expression pattern of SCR was analyzed in Vriesea gigantean and Tillandisia usneoides species chosen during the analysis of Chapter I