Edivani Villaron Franceschinelli

The genetic diversity of Myrciaria floribunda (Myrtaceae) in Atlantic Forest fragments of different sizes

The genetic diversity of Myrciaria floribunda, a common Atlantic Forest tree, was investigated in six populations located in two small fragments (10 and 18 ha), two medium-sized fragments (36 and 44 ha) and one large fragment (3003 ha). Two populations occur in the large fragment. It is expected that smaller fragments should have lower genetic diversity and higher inbreeding. Distances between fragments varied from 0.66 to 10 km. On average 32 young trees smaller than 20 cm basal girth were sampled in each population. Allozyme electrophoresis was carried out, and six loci were scored. The effective number of alleles was lower for populations of the two small fragments (1.46 and 1.51) and higher for populations of the large (1.62 and 1.71) and medium ones (1.69 and 1.84). Small fragments showed lower values of expected and observed heterozygosities than large and medium fragments. Most of the genetic variability occurs within populations, and there was a moderate genetic variation among them ( ˆ θ p = 0.097). Our findings show a tendency of lower genetic diversity within small and isolated fragments and higher genetic differentiation among them. But, few correlations between genetic diversity indices and fragment features (size and isolation) were significant.

High species richness of native pollinators in Brazilian tomato crops

Pollinators provide an essential service to natural ecosystems and agriculture. In tomatoes flowers, anthers are poricidal, pollen may drop from their pore when flowers are shaken by the wind. However, bees that vibrate these anthers increase pollen load on the stigma and in fruit production. The present study aimed to identify the pollinator richness of tomato flowers and investigate their morphological and functional traits related to the plant-pollinator interaction in plantations of Central Brazil. The time of anthesis, flower duration, and the number and viability of pollen grains and ovules were recorded. Floral visitors were observed and collected. Flower buds opened around 6h30 and closed around 18h00. They reopened on the following day at the same time in the morning, lasting on average 48 hours. The highest pollen availability occurred during the first hours of anthesis. Afterwards, the number of pollen grains declined, especially between 10h00 to 12h00, which is consistent with the pollinator visitation pattern. Forty bee species were found in the tomato fields, 30 of which were considered pollinators. We found that during the flowering period, plants offered an enormous amount of pollen to their visitors. These may explain the high richness and amount of bees that visit the tomato flowers in the study areas. The period of pollen availability and depletion throughout the day overlapped with the bees foraging period, suggesting that bees are highly effective in removing pollen grains from anthers. Many of these grains probably land on the stigma of the same flower, leading to self-pollination and subsequent fruit development. Native bees (Exomalopsis spp.) are effective pollinators of tomato flowers and are likely to contribute to increasing crop productivity. On the other hand, here tomato flowers offer large amounts of pollen resource to a high richness and amount of bees, showing a strong plant-pollinator interaction in the study agroecosystem.

Isolation and characterization of microsatellite loci in Cabralea canjerana (Meliaceae).

PREMISE OF THE STUDY Microsatellite primers were developed in the native Neotropical tree species Cabralea canjerana (Vell.) Mart. (Meliaceae) to study population genetics in some Atlantic Forest fragments of Brazil. This species is suitable for use in reforestation and is commercially important due to its high-quality wood. METHODS AND RESULTS In this study, eight microsatellite loci were isolated from an enriched C. canjerana genomic library. These are the first microsatellite loci described for this genus. Genetic diversity analyses were carried out using 30 individuals and six polymorphic loci. An average of 11.2 alleles was found, and the observed heterozygosity was 0.65. CONCLUSIONS The microsatellite markers described here are valuable tools for further population genetic studies of the species.

The post-fire effects on the outcrossing rate of a Brazilian savannah shrub, Helicteres sacarolha A.St.-Hil

The effect of post-fire, plant density and number of flowers per plant on outcrossing rates was examined in a Brazilian savannah shrub, Helicteres sacarolha. Data on number of flowering plants and flowers per plant were collected during the flowering season in January and February of 1994. In October of 1994, a fire swept through the studied area after 30 years of fire absence. The burnt plants of H. sacarolha resprouted, producing flowers and fruits in 1995. Seeds from several plants in both years were collected. Allozyme markers were used to estimate the multilocus outcrossing rates for 1994 and 1995 progenies. After the fire, outcrossing rates increased. In 1995, plants flowered vigorously, increasing flower density and probably pollinator activity. Helicteres sacarolha seems to be fire resistant, like other plant species of the Brazilian savannah, but several plants tagged in 1994 were not found after the fire, and may have died. Thus, although genetic diversity and outcrossing rates increased following the fire in 1994, repeated events of fire may decrease drastically the population size of H. sacarolha, leading to a diminished genetic diversity and outcrossing rates.

Reproductive biology of a highly endemic species: Cipocereus laniflorus N.P. Taylor & Zappi (Cactaceae)

ABSTRACT (Reproductive biology of a highly endemic species: Cipocereus lanifl orus N.P. Taylor & Zappi (Cactaceae)). Cipo-cereus lanifl orus N.P. Taylor & Zappi is an endemic species from the Serra do Caraca, State of Minas Gerais, Brazil. In order to propose conservation strategies for this species, its reproductive strategies were investigated, including reproductive phenology, fl oral biology, fl oral visitors and breeding system. Th e fl owering and fruiting period extends from May to October. Few fl owers per plant open each night, producing up to 0.4 ml nectar, but 30% of them are nectarless. Probably pollen is also off ered as a resource. Fruiting effi ciency of C. lanifl orus (47%) is close to that found in other Cactaceae species . Pollen of this species was detected in Anoura geoff roy, Soricina glossophaga and Pygo-derma bilabiatum bats. Amongst the characteristics related to bat-pollination syndrome found in C. lanifl orus, the cream-white colouring of the internal part of the fl ower, the numerous stamens and the nocturnal anthesis of short duration can be highlighted. Flowers of C. lanifl orus are also visited by Nitidulidae beetles, Trigona fulviventris bees and hummingbirds, however bats are the main pollinators of this species. Finally, as a self-sterile species, C. lanifl orus needs a pollinator and is more susceptible to the risk of extinction if local disturbances aff ect its pollination system.

GENÉTICA DA CONSERVAÇÃO DE Cabralea canjerana (Vell.) Mart. (Meliaceae) EM FRAGMENTOS FLORESTAIS DE MATA ATLÂNTICA NA APA FERNÃO DIAS

A Mata Atlântica e o bioma brasileiro mais severamente afetado pela fragmentacao ambiental. A analise da estruturacao da diversidade genetica, assim como de caracteristicas demograficas e quantitativas, permite inferir parâmetros populacionais importantes para os programas de conservacao de especies ameacadas. Cabralea canjerana ssp. canjerana (Meliaceae) e uma especie arborea dioica considerada modelo para estudos de conservacao da Mata Atlântica. Cento e oitenta e tres individuos de oito subpopulacoes de C. canjerana foram coletados em fragmentos florestais na Area de Protecao Ambiental (APA) Fernao Dias, no Sul do Estado de Minas Gerais, Brasil. Utilizando marcadores microssatelites, a diversidade genetica foi estimada e contrastada com medidas quantitativas e medidas geograficas dessas oito subpopulacoes. Elevados niveis de diversidade genetica foram encontrados. Uma porcao pequena, porem significativa, da variância genetica total esta estruturada entre as populacoes (θ = 0,053), que foram estruturadas em dois grupos distintos. As estimativas dos niveis de diversidade genetica nas populacoes localizadas acima de 1.800 m de altitude foram maiores, corroborando a importância dessas populacoes na manutencao da diversidade genetica. A densidade populacional observada tambem foi maior nos fragmentos de maior altitude (r = 0,849; p-valor = 0,007). Nao houve correlacao significativa entre as variaveis fenotipicas (altura dos individuos e diâmetro a 1,50 m acima do solo) e as medidas de diversidade genetica. Esforcos conservacionistas para que aumentem o fluxo genico entre esses fragmentos florestais devem ser estimulados, principalmente entre os fragmentos de baixa altitude e os fragmentos de elevada altitude. E comprovado que populacoes situadas em elevadas altitudes possuem maior numero de individuos por hectare e, portanto, maiores indices de diversidade genetica. Essas areas podem ser tratadas como repositorio de diversidade genetica, e sua manutencao e de extrema importância. O Codigo Florestal brasileiro determina que essas areas acima de 1.800 m de altitudes sejam consideradas Areas de Protecao Permanente (APP).

Influence of landscape context on the abundance of native bee pollinators in tomato crops in Central Brazil

Evidence shows that pollinator abundance has declined and, consequently, so has their services, which has possible negative impacts on ecosystem functioning. The goal of this study was to evaluate the influence of landscape context at multiple spatial scales on the abundance of bee pollinators of tomato crops in Brazil. Pollinator abundance was obtained from tomato crops grown in a conventional system in the Cerrado region. Around each tomato field circular buffers of 0.75, 1, 1.5, 2, and 3 km radius were defined. Inside each buffer the landscapes were manually classified into native and non-native cover and, the proportion of native vegetation, the relative largest patch size, and the distance of the nearest native vegetation to each field were calculated. Pollinator species were categorized into five groups: Exomalopsis, Centris, Bombus/Eulaema, Halictidae, and all buzz pollinators combined (Buzzers). The results showed that the landscape context influenced the abundance of the five groups of tomato pollinators. Bees with a smaller body size, such as Exomalopsis spp., responded at smaller scales, while bees with a larger body size, such as the Centris and Bombus/Eulaema groups, responded at larger scales. The abundance of all pollinator groups increased with native vegetation cover. Most groups showed higher abundances in landscapes with similar-size fragments. The results reinforce the recommendation for maintaining natural habitats around crop areas, even if fragmented, for the conservation of the tomato pollinator assemblage. These findings are valuable for planning landscape management in the studied area to improve bee conservation, ecosystem services, and food production.

Reproductive success of Cardiopetalum calophyllum (Annonaceae) treelets in fragments of Brazilian savanna

within ten savanna fragments in the municipality of Hidrolandia, Goiˆ as State, Brazil: geographic´coordinates; area of each fragment; distance of each fragment to the nearest neighbour; total number of marked flower in each fragment (FN);numberofmarkedplantsthatproducedfruit(PN);meanandstandarddeviation(SD)offruitsetperflower(F),folliclessetperflower(FO),seedsetperflower(S),pollinatornumberperflower(ABP),reproductiveplantswithina30×30mplot(plantdensity–PD)ineachfragment.Fragment Latitude,Longitude Area(ha) Distance(m) FN PN F FO S ABP PDF1 16

Influência de variáveis limnológicas sobre a comunidade das macrófitas aquáticas em rios e lagoas da Cadeia do Espinhaço, Minas Gerais, Brasil

Plantas aquaticas e amostras de agua foram coletadas em cinco lagoas e tres rios na regiao da Cadeia do Espinhaco, entre dezembro de 2001 e agosto de 2003. Lagoas: Tanque da Fazenda, Comprida, Arame, Americana e Estivinha. Rios: Corrento, Taquaral e Preto. Foram medidas as seguintes variaveis: temperatura da agua, transparencia da coluna de agua, pH, condutividade eletrica, oxigenio dissolvido, demanda bioquimica de oxigenio, demanda quimica de oxigenio, nitrogenio amoniacal, nitrogenio total, fosforo reativo soluvel e fosfato total. Nos ambientes loticos os maiores valores de condutividade foram registrados para os rios Preto e Corrento e foram correlacionados ao aporte de nutrientes naturais. Considerando os ambientes lenticos, nas lagoas Americana e Estivinha foram verificados os maiores valores de condutividade eletrica e DQO. O maior valor de transparencia foi observado na lagoa Tanque da Fazenda. Na ordenacao das especies, foi observada maior riqueza de macrofitas junto as lagoas Americana, Estivinha e Comprida, cujas correlacoes mais fortes foram com os valores de temperatura, pH e concentracao de nitrogenio. A ordenacao das formas biologicas sugeriu a presenca de especies flutuantes fixas nos ambientes mais ricos em nitrogenio e com temperaturas da agua mais elevadas. Provavelmente, a diversidade de ambientes identificada neste estudo e as diferentes caracteristicas fisicas e quimicas estao refletidas na composicao floristica e nas interacoes com o ecossistema.

Pollen flow and pollinator sharing among synchronopatric species of Psychotria (Rubiaceae)

Sympatric plant species that flower at the same time in highly seasonal environments are subject to competitive interference. Many species of the genus Psychotria (Rubiaceae) are sympatric and have an aggregated flowering period, which may have a strong influence on interactions among these species and their pollinators. We assessed the strategies of sympatric species of Psychotria to segregate or share pollinators, and the consequences for intra- and interspecific pollen flow. We sampled pollinators and analyzed flowering phenology, floral tube length, pollinator tongue length and floral nectar production of three sympatric species of Psychotria in the understory of a tropical forest in Brazil. We also marked flowers with fluorescent powder to monitor the flow of pollen. The studied species of Psychotria exhibited a short synchronous flowering period, with the sharing of pollinators and interspecific pollen exchange. The prevalence of shared or unshared pollinators and of intra- or interspecific pollen exchange varied among the studied species. Variation in floral tube length and nectar was not enough to hamper the sharing of most pollinators and pollen flow between Psychotria nitidula and P. hoffmannseggiana. Non-shared pollinators were more common in flowers of P. prunifolia, probably due to its longer floral tube, which can impede the access of shared pollinators. The higher offer of floral nectar by P. prunifolia makes this species more attractive to a greater number of flower visitors. Pollinator sharing seems to have no negative effect on intraspecific pollen flow and on the reproductive success of the studied synchronopatric species of Psychotria.