Successful sexual reproduction in animals and plants requires communication between male and female gametes. In flowering plants, unlike in animals, eggs and sperm cells are enclosed in multicellular embryo sacs and pollen grains, respectively; guided growth of the pollen tube into the ovule is necessary for fertilization. Pollen tube guidance requires accurate perception of ovule-emitted guida...

LOPES, B. DO B.; BERTO, B.P.; MASSAD, F.V.; LOPES, C.W.G. Isospora vanriperorum Levine, 1982 (Apicomplexa: Eimeriidae) in the green-winged saltator, Saltator similis (Passeriformes: Cardinalinae) in southeastern Brazil. [Isospora vanriperorum Levine, 1982 (Apicomplexa: Eimeriidae) no Trinca-ferro Saltator similis Lafresnaye and D’orbigny, 1837 (Passeriformes: Cardinalinae) no sudeste do Brasil]...

Males and females are in conflict over genetic transmission in the evolution of parthenogenesis, because it enhances female reproductive output but deprives the males' genetic contribution. For males, any trait that coerces females into sexual reproduction should increase their fitness. However, in the termite Reticulitermes speratus, queens produce their replacements (neotenic queens) partheno...

The Attwater's prairie chicken (APC; Tympanuchus cupido attwateri Bendire, 1894) has been a federally listed endangered species since 1967. Several captive propagation programs consisting of small populations are being used to keep this species from extinction. Fecal samples were collected from APCs in April 2007 and again in August 2008 from 2 separate captive propagation facilities in Texas a...

The purpose of the present study was to determine the nature of the photoreceptor that controls the light-dependent development of the peanut ovule and embryo, and to determine whether this photoreceptor activity is located in the ovular or the embryonic tissue. Peanut ovules were aseptically excised from surface sterilized gynophores (pegs) and cultured in darkness, continuous far red (FR), or...

Archamia is restricted to a single species, A. bleekeri. A recently described genus, Kurtamia, a reference to a suggested relationship with the enigmatic Kurtus, is the junior synonym of Archamia. Kurtamia bykhovskyi is a junior synonym of A. bleekeri. Archamia is redescribed using osteological, color pattern, pore and free neuromast patterns supplementing those characters used in other publica...

Jatropha curcas belongs to family of Euphorbiaceae, and is an important biological tree species for diesel production. The current descriptions of the phenotypic traits for male and female flowers are not comprehensive and there have been no reports about the process of J. curcas from pollen germination on stigma to pollen tubes conducting fertilization after entering the ovary and ovule. To as...

(Ontogeny and structure of the pericarp and the seed coat of Miconia albicans (Sw.) Triana (Melastomataceae) from “cerrado”, Brazil). Miconia albicans fruit and seed coat ontogeny were described under light microscope. The samples were fixed in formalin-aceto-alcohol (FAA), neutral-buffered formaldehyde solution (NBF) and formalin-ferrous sulphate (FFS) solutions, embedded in plastic resin, sec...

The precise guidance of the pollen tube to the embryo sac is critical to the successful sexual reproduction of flowering plants. We demonstrate here the guidance of the pollen tube to the embryo sac in vitro by using the naked embryo sac of Torenia fournieri, which protrudes from the micropyle of the ovule. We developed a medium for culture of both the ovule and the pollen tube of T. fournieri ...

Flowering plant reproduction requires precise delivery of the sperm cells to the ovule by a pollen tube. Guidance signals from female cells are being identified; however, how pollen responds to those cues is largely unknown. Here, we show that two predicted cation/proton exchangers (CHX) in Arabidopsis thaliana, CHX21 and CHX23, are essential for pollen tube guidance. Male fertility was unchang...