Revisão da anatomia radicular e ontogenia de tilossomos em espécies de Pleurothallidinae (Orchidaceae)
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Data
2019-08-19
Autores
Kedrovski, Halisson Rafael [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Esta tese está organizada em dois Capítulos que tiveram como objetivos: a. descrever e revisar a anatomia radicular na subtribo Pleurothallidinae, b. apontar caracteres anatômicos radiculares que possam identificar táxons, c. reconstruir a história dos caracteres radiculares usando dados genéticos da região ITS disponíveis no GenBank, e por fim, d. mostrar a ontogenia dos tilossomos em Anathallis sclerophylla. No primeiro Capítulo foi analisada a anatomia radicular de 82 espécies distribuídas em 29 gêneros, abrangendo oito das nove Afinidades dentro da subtribo Pleurothallidinae. Concluímos que o velame biestratificado é comum na subtribo, ocorrendo nas oito Afinidades e em mais de 75% das espécies amostradas. Ainda ocorre velame uniestratificado em Lepanthes calodictyon, e velames com três, quatro e cinco camadas em espécies das Afinidades Restrepia e Masdevallia. Reafirmamos a importância taxonômica dos espessamentos parietais do velame apresentando-os de forma detalhada na organografia do complexo velame-exoderme, sendo os padrões morfológicos e sua distribuição entre as camadas do velame uma rica fonte de informação para o reconhecimento dos gêneros na subtribo. Mostramos os tilossomos de 39 espécies e notamos que morfologias mais simples ocorrem nas Afinidades mais basais e morfologias mais complexas ocorrem nas Afinidades mais derivadas. Na exoderme, espessamentos em “O” ou em “∩” ocorrem principalmente nos gêneros mais basais, a exoderme de paredes finas pode ser interpretada como uma característica apomórfica derivada, e a exoderme espessada em “U” em Barbosella é única sinapomorfia encontrada na subtribo. As análises multivariadas mostram grande importância para as caraterísticas do córtex e do cilindro vascular na resolução do dendrograma morfológico. O parênquima cortical pode apresentar-se homogêneo como em Specklinia, ou heterogêneo como em Pabstiella. O cilindro vascular com muitos arcos de protoxilema ocorre com maior frequência nas Afinidades basais, ao contrario do cilindro vascular reduzido, com poucos arcos de protoxilema, característico das Afinidades mais derivadas. Talvez pela grande diversidade do grupo e poucos marcadores morfológicos, os caracteres radiculares se apresentam fortemente homoplásicos, mas a combinação entre eles pode identificar ao menos o gêneros de um morfotipo. Ainda notamos direção no surgimento das apomorfias nos tecidos radiculares quando associamos dados morfológicos aos dados genéticos. Desta forma, este Capítulo contribui substancialmente para o entendimento da anatomia radicular e o comportamento fenotípico da raiz em Pleurothallidnae. No segundo Capítulo, o artigo publicado descreve a ontogenia dos tilossomos das raízes de Anathallis sclerophylla. Concluímos que os tilossomos são crescimentos internos de parede, semelhantes aos encontrados em células de transferência, que se desenvolvem como papilas celulósicas na parede periclinal interna do endovelame, justaposta a célula de passagem da exoderme, na zona de alongamento radicular. Essa estrutura possivelmente funciona como um aparato de membrana e parede para aumentar o transporte de soluto entre epiderme e córtex nas regiões jovens da raiz. A parede do tilossomo desenvolvido é basicamente lignificada, com pouca ou nenhuma deposição de calose nos plasmodesmos, e apresentam lacunas de suberina no seu interior. Por essas características específicas, parecem estar relacionados ao balaço hídrico na raiz adulta.
This thesis is organized in two Chapters that aimed: a. describe and review the root anatomy in the Pleurothallidinae subtribe, b. point out radicular anatomical characters that can identify taxa, c. reconstruct the history of root characters using GenBank genetic data from ITS region, and finally d. to show the ontogeny of tilosomes in Anathallis sclerophylla. In the first Chapter we analyzed the root anatomy of 82 species distributed in 29 genera, covering eight of the nine Affinities within the Pleurothallidinae. We conclude that bistratified velamen is common, occurring in the eight Affinities and in more than 75% of the sampled species. Single layered velamen still occur in Lepanthes calodictyon, in the same way three, four, and five layer occurs in Restrepia and Masdevallia Affinities. We reinforce the taxonomic importance of the velamen parietal thickening, presenting them in detail such a velamen-exodermis complex organogram. The morphological patterns and their distribution between the velamen layers are a rich information source for the genera recognition in the subtribe. We show the tilosomes of 39 species and note that simpler morphologies occur at the early divergent Affinities, and more complex morphologies occur in late divergent ones. In exodermis, “O” or “∩” thickening occurs mainly in basal genera, thin-walled exodermis can be interpreted as a derived apomorphic feature, and “U” thickened exodermis in Barbosella is the only synapomorphy found in the subtribe. Multivariate analysis show high importance for the cortex and vascular cylinder characters to resolution of the morphological dendrogram. The cortical parenchyma can be homogeneous as in Specklinia, or heterogeneous as in Pabstiella. The vascular cylinder with many protoxylem arches occurs more frequently in basal Affinities, opposed to the reduced vascular cylinder with few protoxylem arches, characteristic of the more derived Affinities. Perhaps due to the great diversity of the group and few morphological markers, the root characters are strongly homoplasic, but their combination can identify at least the genera of a morphotype. We still find direction in root apomorphies incidence when we associate morphological with genetic data. Thus, this chapter contributes substantially to the understanding of root anatomy and the phenotypic behavior of the Pleurothallidnae roots. In the second Chapter, the published article describes the tilosomes ontogeny of the Anathallis sclerophylla root. We conclude that tilosomes are wall-ingrowths, similar those found in transfer cells, which develop as cellulosic papillae in the endovelamen inner periclinal wall, over the exodermis passage cells, at the root elongation zone. These structures probably function as wall-membrane apparatus, to increase the solute transport between epidermis and cortex in young root regions. The developed tilosome wall is basically lignified, with little or no deposition of callose in the plasmodesmata, and there are suberin gaps inside its apparatus. Due to these specific morphologic features, they seem to be straightly related to the water balance in the mature root.
This thesis is organized in two Chapters that aimed: a. describe and review the root anatomy in the Pleurothallidinae subtribe, b. point out radicular anatomical characters that can identify taxa, c. reconstruct the history of root characters using GenBank genetic data from ITS region, and finally d. to show the ontogeny of tilosomes in Anathallis sclerophylla. In the first Chapter we analyzed the root anatomy of 82 species distributed in 29 genera, covering eight of the nine Affinities within the Pleurothallidinae. We conclude that bistratified velamen is common, occurring in the eight Affinities and in more than 75% of the sampled species. Single layered velamen still occur in Lepanthes calodictyon, in the same way three, four, and five layer occurs in Restrepia and Masdevallia Affinities. We reinforce the taxonomic importance of the velamen parietal thickening, presenting them in detail such a velamen-exodermis complex organogram. The morphological patterns and their distribution between the velamen layers are a rich information source for the genera recognition in the subtribe. We show the tilosomes of 39 species and note that simpler morphologies occur at the early divergent Affinities, and more complex morphologies occur in late divergent ones. In exodermis, “O” or “∩” thickening occurs mainly in basal genera, thin-walled exodermis can be interpreted as a derived apomorphic feature, and “U” thickened exodermis in Barbosella is the only synapomorphy found in the subtribe. Multivariate analysis show high importance for the cortex and vascular cylinder characters to resolution of the morphological dendrogram. The cortical parenchyma can be homogeneous as in Specklinia, or heterogeneous as in Pabstiella. The vascular cylinder with many protoxylem arches occurs more frequently in basal Affinities, opposed to the reduced vascular cylinder with few protoxylem arches, characteristic of the more derived Affinities. Perhaps due to the great diversity of the group and few morphological markers, the root characters are strongly homoplasic, but their combination can identify at least the genera of a morphotype. We still find direction in root apomorphies incidence when we associate morphological with genetic data. Thus, this chapter contributes substantially to the understanding of root anatomy and the phenotypic behavior of the Pleurothallidnae roots. In the second Chapter, the published article describes the tilosomes ontogeny of the Anathallis sclerophylla root. We conclude that tilosomes are wall-ingrowths, similar those found in transfer cells, which develop as cellulosic papillae in the endovelamen inner periclinal wall, over the exodermis passage cells, at the root elongation zone. These structures probably function as wall-membrane apparatus, to increase the solute transport between epidermis and cortex in young root regions. The developed tilosome wall is basically lignified, with little or no deposition of callose in the plasmodesmata, and there are suberin gaps inside its apparatus. Due to these specific morphologic features, they seem to be straightly related to the water balance in the mature root.
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Palavras-chave
Análises fenéticas, Reconstrução de estado ancestral, Célula de transferência, Phenetic analysis, Ancestral state reconstruction, Transfer cells