Estruturas secretoras florais e coleteres foliares em especies de cerrado de Aspidosperma Mart. e Blepharodon Decne. (Apocynaceae s.l.)
Diego Demarco
DISSERTAÇÃO
Português
(Broch.)
T/UNICAMP D391e
Campinas, SP : [s.n.], 2005.
165p. : il.
Orientadores: Marilia de Moraes Castro, Luiza Sumiko Kinoshita
Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia
Resumo: De acordo com o conceito vigente, Apocynaceae s.l. é composta por cinco subfamílias. No presente trabalho, foram estudadas duas espécies de Aspidosperma e uma de Blepharodon, que integram, respectivamente, as subfamílias mais basal e mais derivada. As espécies foram anatomicamente...
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Resumo: De acordo com o conceito vigente, Apocynaceae s.l. é composta por cinco subfamílias. No presente trabalho, foram estudadas duas espécies de Aspidosperma e uma de Blepharodon, que integram, respectivamente, as subfamílias mais basal e mais derivada. As espécies foram anatomicamente investigadas quanto à ocorrência e caracterização de coléteres em órgãos vegetativos e florais, e com relação à estrutura floral, com ênfase nas estruturas secretoras. A ausência de coléteres em órgãos vegetativos e flores de A. australe Müll. Arg. e A. tomentosum Mart. comprovou que esta estrutura não é universal na família. Coléteres foliares e florais foram encontrados em B. bicuspidatum Fourn. Eles variam em número e são polimórficos. Todos os tipos descritos são inéditos para a família. Os foliares ocupam posição interpeciolar e peciolar, têm origens distintas e desenvolvimento assincrônico, são caducos e a fase secretora varia sazonalmente; os florais são alternos às sépalas, formam-se no início do desenvolvimento floral, são persistentes e secretam até a flor estar em pós-antese. A secreção dos coléteres é heterogênea e produzida em uma única fase. Nos foliares, ela é constituída por mucilagem e compostos fenólicos, enquanto nos calicinais é composta por mucilagem, ácidos graxos e compostos fenólicos. Além de proteger os meristemas vegetativos e florais contra o dessecamento, os coléteres têm função de defesa contra fitófagos nos ramos vegetativos e contra fungos nas flores. Apenas duas estruturas secretoras foram encontradas na flor de A. australe: a epiderme da cabeça dos estiletes e os laticíferos, além de tricomas corolinos com estrutura intermediária entre secretores e tectores e um possível obturador placentário. A cabeça dos estiletes é do tipo mais simples presente na família e os laticíferos são articulados anastomosados. Embora as flores possuam aroma, os osmóforos não foram localizados; tecido nectarífero também não foi encontrado. Em B. bicuspidatum, há seis sítios secretores nas flores: a epiderme da ala da antera, a epiderme da cabeça dos estiletes, a epiderme da câmara estigmática, a epiderme da corona estaminal, os coléteres e os laticíferos articulados anastomosados. Com exceção da epiderme da ala da antera, as demais estruturas permanecem secretando até a antese floral. A estrutura floral de A. australe e de B. bicuspidatum é bastante distinta, mas algumas estruturas secretoras de ocorrência universal na família evidenciam a relação das duas espécies, como a epiderme da cabeça dos estiletes e o mesmo tipo de laticífero. A restrita variedade de estruturas secretoras florais de A. australe corrobora a posição basal do gênero na subfamília e na tribo; a grande diversidade de glândulas florais de B. bicuspidatum e sua complexa estrutura floral confirmam sua posição derivada na família e na subfamília
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Abstract: The current consensus amongst scientists is that the Apocynaceae s.l. is subdivided into five subfamilies. This paper presents a study of two Aspidosperma species and one Blepharodon species. The Aspidosperma and the Blepharodon belong to the most basal and the most derivative subfamilies...
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Abstract: The current consensus amongst scientists is that the Apocynaceae s.l. is subdivided into five subfamilies. This paper presents a study of two Aspidosperma species and one Blepharodon species. The Aspidosperma and the Blepharodon belong to the most basal and the most derivative subfamilies respectively. An anatomical study of the species was carried out in order to look into the characterization and occurrence of colleters in vegetative and floral organs. Also, the same study was made in relation to the floral structure, focusing on the secretory structures. The absence of colleters in vegetative organs and flowers of the A. australe Müll. Arg. and the A. tomentosum Mart. proved that this structure is not universal in the
family. Foliar and floral colleters were found in the B. bicuspidatum Fourn. They are polymorphic and they vary in number. The described colleters are new in the family. The foliar colleters occupy an interpetiolar position, and they have distinct origins and asynchronous developments. Also, they are deciduous and the secretory phase varies seasonally. The floral colleters alternate with the sepals. They are formed at the beginning of the floral development. They are persistent and they secrete until the flower is in postanthesis. The secretion of the colleters is heterogeneous and it is produced in a single phase. In the foliar colleters, it is made up of the mucilage and the phenolic compounds. But in the calycine, it is composed of the mucilage, fatty acids and phenolic compounds. Besides protecting the vegetative and floral meristems from desiccation, the colleters also protect against phytophagous insects in vegetative branches and against fungi in flowers. Only two secretory structures were found in the A. australe flower: the stylehead epidermis and the laticifers, besides the corolline trichomes with an intermediate structure between glands and tector trichomes, and possibly an obturator from the placenta. The style-head is one of the simplest structures in the family, and the laticifers are unbranched articulated. Although the flowers have an scent, the osmophores were not found, nor was the nectariferous tissue. In the B. bicuspidatum, there are six glands in the flowers: the anther wing epidermis, the style-head epidermis, the stigmatic chamber epidermis, the staminal corona epidermis, the colleters, and the unbranched articulated laticifers. Except for the anther wing epidermis, the other structures continue secreting until the floral anthesis.
The floral structure of the A. australe and the B. bicuspidatum is very distinct, but some secretory structures that are universal (in the family) show the relationship between the two species, such as the style-head epidermis and the same type of laticifer. The restricted variety of floral secretory structures of the A. autrale confirm the basal position of the genera in the subfamily and in the tribe, a wide variety of floral glands of the B. bicuspidatum and its complex floral structure confirm its derivative position in the family and subfamily Ver menos
family. Foliar and floral colleters were found in the B. bicuspidatum Fourn. They are polymorphic and they vary in number. The described colleters are new in the family. The foliar colleters occupy an interpetiolar position, and they have distinct origins and asynchronous developments. Also, they are deciduous and the secretory phase varies seasonally. The floral colleters alternate with the sepals. They are formed at the beginning of the floral development. They are persistent and they secrete until the flower is in postanthesis. The secretion of the colleters is heterogeneous and it is produced in a single phase. In the foliar colleters, it is made up of the mucilage and the phenolic compounds. But in the calycine, it is composed of the mucilage, fatty acids and phenolic compounds. Besides protecting the vegetative and floral meristems from desiccation, the colleters also protect against phytophagous insects in vegetative branches and against fungi in flowers. Only two secretory structures were found in the A. australe flower: the stylehead epidermis and the laticifers, besides the corolline trichomes with an intermediate structure between glands and tector trichomes, and possibly an obturator from the placenta. The style-head is one of the simplest structures in the family, and the laticifers are unbranched articulated. Although the flowers have an scent, the osmophores were not found, nor was the nectariferous tissue. In the B. bicuspidatum, there are six glands in the flowers: the anther wing epidermis, the style-head epidermis, the stigmatic chamber epidermis, the staminal corona epidermis, the colleters, and the unbranched articulated laticifers. Except for the anther wing epidermis, the other structures continue secreting until the floral anthesis.
The floral structure of the A. australe and the B. bicuspidatum is very distinct, but some secretory structures that are universal (in the family) show the relationship between the two species, such as the style-head epidermis and the same type of laticifer. The restricted variety of floral secretory structures of the A. autrale confirm the basal position of the genera in the subfamily and in the tribe, a wide variety of floral glands of the B. bicuspidatum and its complex floral structure confirm its derivative position in the family and subfamily Ver menos
Castro, Marilia de Moraes, 1953-
Orientador
Kinoshita, Luiza Sumiko, 1947-
Coorientador
Kraus, Jane Elizabeth
Avaliador
Carmello-Guerreiro, Sandra Maria, 1963-
Avaliador
Marcondes-Ferreira, Washington
Avaliador
Estruturas secretoras florais e coleteres foliares em especies de cerrado de Aspidosperma Mart. e Blepharodon Decne. (Apocynaceae s.l.)
Diego Demarco
Estruturas secretoras florais e coleteres foliares em especies de cerrado de Aspidosperma Mart. e Blepharodon Decne. (Apocynaceae s.l.)
Diego Demarco
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