Biologia reprodutiva de doze especies simpatricas de Malpighiaceae em mata semidecidua do sudeste brasileiro

AUTOR(ES)
DATA DE PUBLICAÇÃO

2001

RESUMO

The reproductive phenology, pollination biology and breeding system of twelve species of Malpighiaceae (Banisteriopsis adenopoda (A.Juss.) B.Gates, B. lutea (Griseb.) B.Gates, B. muricata (Cav.) Cuatrec., B. pubipetala (A.Juss.) Cuatrec., Dicella bracteosa (A.Juss.) Griseb., Heteropterys aceroides Griseb., Mascagnia anisopetala (A.Juss.) Griseb., M cordifolia (A.Juss.) Griseb., M sepium (AJuss.) Griseb., Stigmaphyllon lalandianum A.Juss., Tetrapterys guilleminiana A.Juss., T. phlomoides (Spreng.) Nied.) were studied in semi-deciduous forest (Reserva Municipal de Santa Genebra/RSG), in Campinas, SP, for tive years. The occurrence of visitors to flowers of these species was compared with data collected in the 1980s. These species are lianas and grow over the vegetation at the edge of the forest. There are species with flowers, fruit and diaspores in dispersal throughout the year. The studied community has two flowering peaks, both out of dry season. The peak of fructification and dispersal occurr at the end of the dry season and during the transition to the rainy season, a more appropriate period for the dispersal of anemocorous fruit of the majority of these species and for their seed germination. The inflorescences are racemses or cymoses and formed by dense dichasial units. The flowers are zygomorphic, pentamerous, yellow or pink, diurnal and have perceptible odor (except in B. lutea and T. phlomoides). The petals are c1awed and one of them, the posterior petal, differs from the others and serves as an orientation guide and support for pol1inators. Oil is the main floral resource offered to pollinators, and is produced in epithelial glands (= elaiophores) which occur in pairs in the sepals. In B. lutea and some individuais of B. muricata and H aceroides the flowers are eglandular and offer on1y pollen. Eglandular flowers of B. lutea probably mimic B. pubipetala flowers with glands. Floral mutualism may be occurring between B. adenopoda and B. muricata. Eleven species have hermaphrodite flowers and the interespecific pollen viability is high1y variable, between 57-94%. B. pubipetala is gynodioecious and in RSG their flowers are functionally female (pseudo-hermaphrodite), as their anthers do not open and the pollen has low viability. The herkogamy and the presence of a stigmatic cutic1e, limit the occurrence of spontaneous self-pollination in hermaphrodite flowers. Six species show a certain degree of compatibility, four species present, probably, self-incompatibility of late action and B. pubipetala is agamospermous. The fragmentation of the RSG seems to be compromising the sexual reproduction of the studied species, a fact which is evidenced by the low rate of fructification observed in this study. Bees of the family Anthophoridae, of the genera Centris, Epicharis, Monoeca, Paratetrapedia and Tetrapedia totaled 97,4% ofthe visits to the flowers. The speeies of Centris, Epicharis and/or Monoeca were the main pollinators and basieally they eolleet oil. While eolleeting oil, these bees settle on the flower, grasp the posterior petal with their jaws, insert the anterior and medium legs between the petals and serateh the elaiophores; simultaneously rubbing the anthers and stigmas with their venters. The oil eolleeting behavior favors the rupture of the stigmatie eutiele and the deposition of a large load of pollen over/inside the stigmas. Epicharis affinis, E. fiava, E. schrottkyi e Monoeca sp. 1 eolleet pollen by vibration from the flowers of some species. Centris showed a larger riehness ofspecies (10 spp.) but the speeies of Epicharis (5 spp.) showed a larger visitation rate. C. collaris, C. mocsaryi, E. affinis, E. fiava and E. schrottkyi were the main pollinators and/or the secondary of the majority of the speeies, totaling about 50% of the registered visits. Monoeca sp. 3 was the main pollinator of H. aceroides. Usually, the speeies of Paratetrapedia and Tetrapedia are plunderers when eolleeting oil and aeeidental pollinators when eollecting pollen. Four speeies ofthe family Apidae ean also pollinate the flowers when eolleeting pollen. The speeies of the family Anthophoridae oeeur throughout the year, but mainly in warmer and wet periods. Afier a decade, the speeies riehness and the pattem of oeeurrenee of the Anthophoridae family of bees in the species of Malpighiaeeae are relatively similar, suggesting that the eonditions of the RSG are appropriate for the survival and permanenee of these bees. In this aspeet, the Malpighiaeeae are of fundamental importanee in the RSG beeause they eonstitute the main oil souree for the anthophorid bees

ASSUNTO(S)

malpiguiacea fenologia polinização reprodução

ACESSO AO ARTIGO

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