Pollination biology in Jacaranda copaia (Aubl.) D. Don. (Bignoniaceae) at the "Floresta Nacional do Tapajós", Central Amazon, Brazil

Jacaranda copaia (Aubl.) D. Don is a pioneer tree widespread in the Brazilian Amazon, usually found colonizing forest gaps and altered areas, and the forest fragment edges. This study investigated aspects of the floral biology, breeding system and pollinators of J. copaia trees. Flowering lasts from August to November, during the low rainfall period extending up to four weeks per tree and 3-4 months for the population as a whole, characterizing a cornucopia flowering pattern. The fruit set ends in the beginning of the rainy season, with wind dispersed winged seeds. Fruit set from open pollination was 1.06% (n = 6,932). Hand pollination using self-pollen (n = 2,099) did not set fruits. Cross-pollination resulted in 6.54% fruit set (n = 2,524), representing six times more than the natural pollination rate (1.06%, n = 6,932). Flowers excluded from insect visitation (automatic self-pollination) did not set fruits (n = 5,372). Pollen tube growth down to ovary was detected under fluorescence microcoscopy in cross-pollinated and selfed pistils. The species is an obligate allogamous plant, with late-acting self-incompatibility system. Approximately 40 species of native bees visited the flowers, but the main pollinators were medium-sized solitary bees as Euglossa and Centris species due to the compatibility between their body sizes with the corolla tube, direct contact with the reproductive structures and high frequency of visits.

Is the pollination efficiency of long-lived orchid flowers affected by age?

The long-lived flowers of orchids increase the chances of pollination and thus the reproductive success of the species. However, a question arises: does the efficiency of pollination, expressed by fruit set, vary with the flower age? The objective of this study was to verify whether the flower age of Corymborkis flava(Sw.) Kuntze affects pollination efficiency. The following hypotheses were tested: 1) the fruit set of older flowers is lower than that of younger ones; 2) morphological observations (perianth and stigmatic area), stigma receptivity test by using a solution of hydrogen peroxide and hand-pollination tests are equally effective in defining the period of stigmatic receptivity. Flowers were found to be receptive from the first to the fourth day of anthesis. Fruit set of older flowers (third and fourth day) was lower than that of younger flowers. Morphological observations, the stigma receptivity test and hand-pollinations were equally effective in defining the period of stigmatic receptivity. However, to evaluate the maximum degree of stigma receptivity of orchid species with long-lived flowers, we recommend hand-pollinations, beyond the period of receptivity.

Observations on the pollination of Rhabdodendron macrophyllum (Spruce ex Benth.) Huber.

The species Rhabdodendron macrophyllum (Spr. ex Benth.) Hub. (Rhabdondendraceae) was observed in order to determine its pollination mechanism. Although it flowers around the year, there are flowering peaks when it is visited by several species of pollen-gathering bees. The principal floral visitors are two species of trigonid bees and one Melipona. The Melipona and one other visitor used the buzz method to extract pollen from the longitudinally dehiscent anthers. The trigonid bees collected pollen without buzzing. The flowers open around 6:00 a.m. and are available to the bess until about 10:30 a.m. Pollinator exclusion experiments showed that this species sets fruit equally by self fertilization.

Pollination efficiency of the stingless bee Melipona subnitida on greenhouse sweet pepper

The present study was carried out in Northeastern Region of Brazil, in order to investigate the use of stingless bee Melipona subnitida Ducke in the pollination of greenhouse sweet pepper (Capsicum annuum L.). Treatments of hand cross-pollination, hand self-pollination, pollination by bees and restricted pollination were performed. Results showed that despite sweet pepper flowers are considered autogamous, this crop benefits from pollination by M. subnitida, producing fruits significantly heavier and wider, containing a greater number of seeds and of better quality (lower percentage of malformed fruits) than self-pollinated sweet pepper. Thus, M. subnitida can be considered an efficient pollinator of greenhouse sweet pepper.

Pollination requirements of seeded and seedless mini watermelon varieties cultivated under protected environment

The objective of this work was to evaluate the floral biology and pollination requirements of seeded and seedless mini watermelon varieties, and to determine the best varieties to cultivate under protected environment. Three seedless (HA-5106, HA-5158, and HA-5161) and two seeded (Minipol and Polimore) genotypes were tested. Flowers were monitored from the pre-anthesis stage to senescence, and fruit quality was also evaluated. The evaluated treatments were hand-geitonogamous pollination (MG), cross-pollination with pollen from the Polimore variety (MCP), cross-pollination with pollen from the Minipol variety (MCM), and restricted pollination. All varieties had monoecious plants with diclinous flowers, and the stigmas remained receptive throughout anthesis. Fruit set rates of 84.62% (MG), 61.54% (MCP), 48% (MCM), and 0% (restricted) were obtained for seeded varieties, but of 0% (MG), 76.36% (MCP), 82.69% (MCM), and 0% (restricted) for seedless varieties. Fruits did not differ in quality among treatments within each genotype. Therefore, all the studied varieties require a pollination agent and diploid pollen for fruit set to occur, regardless of the donor variety; and Minipol or Polimore with HA-5106 or HA-5158 are the varieties recommended for cultivation in protected environment.

Blueberry pollination in southern Brazil and their influence on fruit quality

Blueberry (Vaccinium ashei) is a relatively new crop in cultivation under Southern Brazil conditions. The first collection introduced in the area was formed by rabbiteye cultivars which need insect pollinators and also pollinizers. The aim of this work was to observe if there were differences between pollinizers on fruit quality of the commercial cultivar and also to observe the most effective and frequent insect pollinators, under natural conditions. It was concluded that pollen source has an effect on quality of blueberry fruits. Bumblebees are the most efficient pollinators; however the species found in southern Brazil are different from the ones mentioned in the U.S. literature.

Pollination and other biotic interactions in figs of Ficus eximia Schott (Moraceae)

During the period from 1992 to 1997, interactions of several organisms and Ficus eximia figs, a monoecious species, were studied in plants located in Campinas/SP and Londrina/PR (Brazil). Ficus eximia is pollinated by a single fig wasp species, Pegoscapus sp. (Hymenoptera: Agaonidae, Agaoninae), but also visited by other 14 non-pollinating wasps (Agaonidae, Eurytomidae, Torymidae). Mites (Tarsonemidae), nematodes (Diplogasteridae) and fungi which use the body of the pollinating fig wasp to disperse themselves were also observed.

Fly pollination and pollinator sharing in two synchronopatric species: Cordia multispicata (Boraginaceae) and Borreria alata (Rubiaceae)

The floral biology of Cordia multispicata (Boraginaceae) and Borreria alata (Rubiaceae) was studied in natural populations in a fragment of the Atlantic forest in Pernambuco, northeastern Brazil. Both species flower during almost the whole year. Cordia multispicata is a shrubby species with white, distylous and tubular flowers. Borreria alata is a herbaceous species. Its flowers are whitish, tubular and have a polymorphism in relation to the size of their style. Floral anthesis in both species begins at 6:00 a.m. Sugar concentration in the nectar was about 16% in C. multispicata and 30% in B. alata. Nine species of flies, mainly of the genus Palpada (Syrphidae), were observed visiting flowers of the two species. Seven of them were observed visiting and pollinating flowers of both C. multispicata and B. alata. Two species visited only flowers of C. multispicata, whereas no fly was exclusive to B. alata flowers. Both species have similar flower morphology, flowering time, habitats in the forest and establish populations very close to each other. These facts can favour the pollinators’ sharing and increase pollinator attraction.

Pollination ecology of Tabebuia aurea (Manso) Benth. & Hook. and T. ochracea (Cham.) Standl. (Bignoniaceae) in Central Brazil cerrado vegetation

The pollination ecology and breeding systems of Tabebuia aurea (Manso) Benth. & Hook., and T. ochracea (Cham.) Standl. were investigated in an area of cerrado vegetation in the Federal District of Brazil. These species occur sympatrically, flower massively and synchronously for a month, during the dry season (July to September). Both have diurnal anthesis, with similar floral structures, a yellow tubular corolla and produce nectar. Fourteen species of bees visited both Tabebuia species, but, only three Centris species and Bombus morio, were considered potential pollinators, because of their high frequency on the flowers and their efficiency in carrying pollen. Tests on the breeding systems of T. aurea and T. ochracea demonstrated that boths species are self-incompatible, with late-acting self-incompatibility. The proportion of fruit set from cross pollination (T. aurea 17.2% and T. ochracea 12.3%) in both species was low considering the great number of flowers displayed. This suggests a lack of maternal resources for fruit-set. The great amount of seeds per fruit (about 92 in T. aurea and 285 in T. ochracea) may represent an investment of maternal resources allocated on higher quality of fertilized ovules.

Reproductive phenology, pollination and seed dispersal syndromes on sandstone outcrop vegetation in the "Chapada Diamantina", northeastern Brazil: population and community analyses

Vegetation on rock outcrops in the "Chapada Diamantina" (soil islands) is often aggregated and surrounded by nude rock surfaces, thus creating natural units with well defined limits. The flowering and fruiting cycles of plants on 58 soil islands at altitudes between 1,100 and 1,140 meters above sea leavel were analyzed at Mãe Inácia Peak (12°27' S and 41°28' W) in the "Chapada Diamantina", Bahia, Brazil. The presence/absence of flowering and fruiting species on each soil island, and their respective cover areas were analyzed at both the population and community levels, and the phenophases of flowering and fruiting were observed during 24 successive months. The analyses of pollination and seed dispersal syndromes indicated that animals are more important in pollination than in seed dispersal (which is predominantly by anemochory and autochory). The flowering and fruiting of plants with animal pollination syndromes were correlated with rainfall and temperature. The flowering season varied during the year according to the pollination syndrome involved: entomophily was predominant from summer through autumn, ornithophily was predominant during winter, and anemophily in the spring. The staggered timing of flowering and fruiting among different species provides a nearly continuous supply of resources for the local fauna.

Pollination and fruit set in pumpkin (Cucurbita pepo) by honey bees

Species of Cucurbitaceae are cultivated worldwide and are depend on bee pollination for fruit set. Field and lab experiments were conducted at Cornell University, Ithaca, NY, during 1996 and 1997 to determine "Howden" pumpkin (Cucurbita pepo L.) pollen removal and deposition by honeybees and factors relating to male flower attractiveness. Several parameters were evaluated in flowers at anthesis: (1) removal of pollen from anthers by honey bees, (2) pollen deposition on the stigma by honey bees, (3) amount of pollen on the body of honey bees, (4) fruit set after bee pollination, and (5) male flower nectary's pores and flower attractiveness. Honey bees carried between 1,050 to 3,990 pollen grains and 13,765 were removed from an anther after one visit. The amount of pollen deposited on the stigma by the honey bees varied according to the number of visits, from 53 grains with one visit, to 1,253 grains with 12 visits, and the mean number of grains in each visit varied from 53 to 230 grains. The percentage of established fruits was higher (100%) when the flowers received 12 visits of Apis mellifera, corresponding to a load 1,253 pollen grains. The attractiveness of the male flower for pollen and nectar collection was increased by the degree of opening of the access pore to the nectary in the flower.

CONSTITUTIVE MELANIN IN THE CELL WALL OF THE ETIOLOGIC AGENT OF LOBO'S DISEASE

Lobo's disease is a chronic granulomatous disease caused by the obligate pathogenic fungus, whose cell walls contain constitutive melanin. In contrast, melanin does not occur in the cell walls of Paracoccidioides brasiliensis when stained by the Fontana-Masson stain.

Incidence of anti-toxoplasma antibodies in women with high-risk pregnancy and habitual abortions

Toxoplasmosis is a zoonosis caused by Toxoplasma gondii, an obligate intracellular parasite. In pregnant women on the worldwide scale, there are seroprevalences from 7% to 51.3% and in women with abnormal pregnancies and abortions the seroprevalences vary from 17.5% to 52.3%. In Mexico, seropositivity has been found to vary from 18.2% to 44.8% in women with abnormal deliveries or abortions. This study's aim was to determine the incidence oflgG and IgM anti-Toxoplasma antibodies in women at the Gineco-Obstetrics Hospital of the Western Medical Center of the Mexican Social Security Institute. Three hundred and fifty women with high-risk pregnancies were studied, and 122 (34.9%) were found to be IgG seropositive and 76 (20.7%) were IgM positive. In one group of women with habitual abortions there were 48 (44.9%) with the preseiwe of IgG antibodies and 33 (33-3%) were IgM seropositive. Seropositivity was analyzed according to age, occupation, socio-economic level, eating raw or poorly cooked meat, and living with cats.

Approaches towards tick and tick-borne diseases control

Ticks are obligate haematophagous ectoparasites of wild and domestic animals as well as humans, considered to be second worldwide to mosquitoes as vectors of human diseases. Tick-borne diseases are responsible worldwide for great economic losses in terms of mortality and morbidity of livestock animals. This review concerns to the different tick and tick-parasites control methods having a major focus on vaccines. Control of tick infestations has been mainly based on the use of acaricides, a control measure with serious drawbacks, as responsible for the contamination of milk and meat products, as a selective factor for acaricide-resistant ticks and as an environmental contaminant. Research on alternatives to the use of acaricides is strongly represented by tick vaccines considered a more cost-effective and environmentally safe strategy. Vaccines based on the Bm86 tick antigen were used in the first commercially available cattle tick vaccines and showed good results in reducing tick numbers, affecting weight and reproductive performance of female ticks which resulted in reduction of cattle tick populations over time and consequently lower reduction of the pathogen agents they carry.

Observations on flower visitors to Bertholletia excelsa H.B.K. and Couratari tenuicarpa A.C. Sm. (Lecythidaceae)

Bees visiting flowers of Bertholletia excelsa. (Brazil Nut tree) and Couratari tenuicarpa were collected, their behavior described and the pollen found clinging to their dorsal thorax and stored on their legs was identified. Female bees of Xylocopa frontalis(Olivier) and males of Eulaema mocsaryi (Friese) are apparently effective pollinators of Couratari in igapó near Manaus. Female bees of Euplusia seabrai Moure in litt., Epicharis umbraculata (Fabricius), Epicharis rustica (Olivier) and Eulaema nigrita(Lepeletier), as well as male bees of Eulaema cingulata(Fabricius) and Eulaema nigrita are apparently effective pollinators of adult Brazil Nut trees in the Aleixo plantation near Manaus. Only large bees capable of uncurling the floral androecium can effectively pollinate Couratari or Bertholletia.Pollen analysis indicated that all bees captured carried pollen of the host tree in question and had been foraging on flowers of plant species common in secondary growth. Secondary growth near the Aleixo plantation supports a bee guild which appeared to effectively pollinate almost every flower on the Brazil Nut tree studied. Proximity to primary forest (and to those Euglossine bee species which occur only in primary forest) therefore does not appear to be necessary for pollination of Brazil Nut trees.In the Aleixo plantation chronic low fruit set is probably due to some factor other than pollination. Since natural occurrences of Brazil Nut trees to the north and south of Manaus are associated with a higher soil fertility, low production at the Aleixo plantation may be due to deficiencies of the soil.