Structural studies on the reproductive organs of Tapirira guianensis Aubl. (Anacardiaceae)

Author(s)

Elisabeth Emília Augusta Dantas Tölke

• Document type: Master's Dissertation
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia
• Defense date: 2013-07-05

Examining board members

Sandra Maria Carmello Guerreiro; Ana Paula Stechhahn Lacchia; Tatiane Maria Rodrigues

• Advisor: Silvia Rodrigues Machado; Sandra Maria Carmello Guerreiro

Abstract

Tapirira guianensis Aubl. (Anacardiaceae) well-known as "pau-pombo" is an important species with uses as timber, in medicine and can be employed recovering degraded areas and riparian forests. Several substances are produced in specific secretory structures and the presence of cavities and ducts are universal features in the family. In literature is reported the presence of an intrastaminal receptacular nectary in the flowers of many Anacardiaceae, however anatomical and histochemical recent studies did not support the nectar secretion by this structure. Furthermore, in other studies were found the persistence of intrastaminal receptacular gland in T. guianensis ripe fruits and the presence of a secretory endocarp in unripe fruits. Allied these factors, the ontogeny of fruits and seeds is also a relatively unexplored subject, in contrast with the large number of species from this family. The fruit anatomy of Anacardiaceae has proved great systematic value. Thus, the present study verified T. guianensis structure and ultrastructure of flowers and fruits intrastaminal gland and examined the nature of substances produced as well the fruit and seed development. With the results obtained it was possible provide that the T. guianensis floral gland of hermaphrodite flowers is a mixed secretion gland, producing nectar with sucrose predominance, lipids and fenolic substances. Ultrastructurally, this gland undergoes deep changes during the development of the flower, originally rich in amyloplasts and subsequently chloroplasts devoids of starch and mitochondria replete with oil droplets, indicating the change in the secretion predominantly hydrophilic to lipophilic. With respect to the fruit anatomy, it was observed characteristics typical of the tribe Spodieae, but some of them indicate a condition less derived of this species, such as lack of operculum and endocarp relatively thin compared to other species of the same tribe. Pericarp has a large number of resiniferous ducts in mesocarp region, and epicarp produces phenolic substances and lipids. By transmission electron microscopy it was possible to observe the way of secretion, the organelles involved in process and the cell structure. Seed comes from a single ovule, anatropous, bitegmic, crassinucelate with longe funicle. Seed does not have mechanical layer, has exotest and endotegmen rich in phenolic substances, crystals in mesotegmen, development of partial pachycalaza, phenolic and lipid hypostasis, permanence of the funicle attached to the seed-coat, forming a vestigial aril. The embryo stores large amounts of protein and starch, indicating a transitional condition in the species, because Anacardiaceae reserves comprehend mainly protein and lipids. Fruit and seed showed anatomical characteristics possibly related to dispersion, like formation of aerenchyma in the inner mesocarp and mesotest, starch accumulations in mesocarp. The work brings contributions in the study of Anacardiaceae floral glands and in the area of fruit and seeds ontogeny (AU)

• FAPESP's process: 11/02293-0 - Tapirira guianensis Aubl. (Anacardiaceae): an investigation about the secretions produced in flower and fruit
• Grantee: Elisabeth Emília Augusta Dantas Tölke
• Support Opportunities: Scholarships in Brazil - Master