Estrutura e função das glândulas florais e dos nectários foliculares em Diplopterys Pubipetala (A. JUSS.) W. R. Anderson & C. Cav. Davis (Malpighiaceae)
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Data
2008-04-30
Autores
Possobom, Clívia Carolina Fiorilo [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Diplopterys pubipetala é uma malpiguiácea amplamente distribuída pelo Brasil e apresenta glândulas no cálice, corola, estames e folhas, cuja estrutura, funcionamento e significado ecológico são desconhecidos. Com o objetivo de entender a dinâmica de secreção e o papel destas glândulas, foram estudados aspectos anatômicos, histoquímicos e ultraestruturais, além de registros fenológicos e do comportamento dos visitantes em uma população ocorrente em área de cerrado. As glândulas calicinais estão dispostas aos pares na face abaxial das sépalas, são conspícuas e constituídas por epiderme secretora em paliçada e parênquima especializado vascularizado por xilema e floema. As glândulas da corola ocorrem nas margens fimbriadas de todas as cinco pétalas. São diminutas e constituídas por epiderme secretora unisseriada envolvendo um pequeno grupo de células parênquimáticas vascularizadas ou não. As glândulas presentes na pétala posterior são vascularizadas e estruturalmente mais desenvolvidas do que as glândulas presentes nas pétalas laterais, não vascularizadas. Nos estames o conectivo apresenta superfície secretora constituída por células epidérmicas globulares. Constatou-se que todas as glândulas florais desempenham funções como atrativos primários ou secundários; além disto, o conectivo glandular está relacionado também com o aumento da eficiência na transferência de pólen, sendo fundamentais na manutenção da interação com os vetores de pólen e na reprodução da população de D. pubipetala estudada. Os nectários são diminutos e distribuídos na margem do limbo, sendo mais desenvolvidos os localizados na base e no ápice do limbo. Estes nectários são anatomicamente semelhantes às glândulas do cálice, entretanto são vascularizados predominantemente por floema. São ativos unicamente em folhas jovens e sua secreção representa...
Diplopterys pubipetala is a Malpighiaceae species widely distributed in Brazil and presents glands in calyx, corolla, stamens and leaves whose structural, functional and ecological aspects are unknown. In order to understand the secretion dynamic and the role of these glands, anatomical, histochemical and ultrastructural aspects were studied, besides phenological and visitors behavior records in a cerrado population. The calyx glands occur in pairs in the sepal abaxial surface and are constituted by secretory epidermis and specialized parenchyma with vascular supply of xylem and phloem. The corolla glands occur in the fimbriate margins of all the five petals. They are very small and constituted by unisseriate secretory epidermis that involves a small group of parenchyma cells vascularized or not. The posterior petal glands are vascularized and structurally more developed than lateral petal glands which are not vascularized. In the stamen, the connective shows secretory surface constituted by globular epidermal cells. All these floral glands play important roles as primary and secondary attractive; furthermore, the glandular connective is also related to the increase of pollen transfer efficiency, being essential for maintenance of the interactions with pollen vectors and in the reproduction of D. pubipetala studied population. The nectaries are very small and occur in all the margin of the leaf blade, being more developed these located in the apex and in the base. These nectaries are anatomically similar to the calyx glands, although are vascularized predominantly by phloem. They are only active in young leaves whose secretion represents a food resource for aggressive ants, suggesting the existence of benefical interactions between nectaries and ants. The histochemical tests revealed that the secretion is predominantly lipophilic in floral glands and predominantly hidrophilic in the leaf... (Complete abstract click electronic access below)
Diplopterys pubipetala is a Malpighiaceae species widely distributed in Brazil and presents glands in calyx, corolla, stamens and leaves whose structural, functional and ecological aspects are unknown. In order to understand the secretion dynamic and the role of these glands, anatomical, histochemical and ultrastructural aspects were studied, besides phenological and visitors behavior records in a cerrado population. The calyx glands occur in pairs in the sepal abaxial surface and are constituted by secretory epidermis and specialized parenchyma with vascular supply of xylem and phloem. The corolla glands occur in the fimbriate margins of all the five petals. They are very small and constituted by unisseriate secretory epidermis that involves a small group of parenchyma cells vascularized or not. The posterior petal glands are vascularized and structurally more developed than lateral petal glands which are not vascularized. In the stamen, the connective shows secretory surface constituted by globular epidermal cells. All these floral glands play important roles as primary and secondary attractive; furthermore, the glandular connective is also related to the increase of pollen transfer efficiency, being essential for maintenance of the interactions with pollen vectors and in the reproduction of D. pubipetala studied population. The nectaries are very small and occur in all the margin of the leaf blade, being more developed these located in the apex and in the base. These nectaries are anatomically similar to the calyx glands, although are vascularized predominantly by phloem. They are only active in young leaves whose secretion represents a food resource for aggressive ants, suggesting the existence of benefical interactions between nectaries and ants. The histochemical tests revealed that the secretion is predominantly lipophilic in floral glands and predominantly hidrophilic in the leaf... (Complete abstract click electronic access below)
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Botânica - Morfologia, Flores, Folhas, Floral glands, Leaf nectaries, Malpighiaceae
Como citar
POSSOBOM, Clívia Carolina Fiorilo. Estrutura e função das glândulas florais e dos nectários foliculares em Diplopterys Pubipetala (A. JUSS.) W. R. Anderson & C. Cav. Davis (Malpighiaceae). 2008. 128 f. Dissertação (mestrado) - Universidade Estadual Paulista, Instituto de Biociências de Botucatu, 2008.