Correlação entre floração, frutificação e variáveis ambientais em Solanum lycocarpum. A. St. Hil, Solanaceae / Correlation between flowering, fructification and environmental variables in Solanum lycocarpum A. St.-Hil, Solanaceae

A lobeira (S. lycocarpum) é uma espécie típica e abundante do Cerrado, que ocupa principalmente ambientes antropizados. Possui características interessantes do ponto de vista da biologia reprodutiva, que provavelmente estão favorecendo a ampla ocupação pela espécie. Tendo em vista que a planta floresce e frutifica durante todo o ano, o presente estudo teve por objetivo verificar se existe correlação entre floração, frutificação e variáveis ambientais (temperatura, umidade e precipitação), como suporte para estudos futuros referentes à biologia reprodutiva e ecologia de espécies de plantas do Cerrado. Foi escolhida uma população de lobeira situada no município de Morrinhos, Sul do estado de Goiás, composta de 34 plantas em fase reprodutiva. Todas as plantas foram georreferenciados com um aparelho GPS. Foram feitas observações mensais durante 13 meses (junho de 2005 a julho de 2006) e quantificados flores abertas e frutos produzidos nos intervalos entre observações. Pode-se inferir alta conversão de flores hermafroditas em frutos. Por meio da correlação de Spearman, pode-se constatar correlação positiva entre floração e precipitação e umidade, o mesmo, aparentemente, não ocorre para frutificação.

Solanum lycocarpum (lobeira) is a typical and abundant species of brazilian Cerrado, which occupies mainly surrounding disturbed areas. It has interesting characteristics from the point of view of reproductive biology, that probably are favoring the large occupation of habitats by the species. Based on the fact that the species produces flowers and fruit during all the year, the present study had the purpose to verify the association between flower and fruit production with environmental variables (temperature, relative humidity and precipitation), aiming to support future studies referring to reproductive biology and ecology of plant species from Cerrado biome. A population of S. lycocarpum composed of 34 plants in reproductive phase, situated in Morrinhos, south of the State of Goiás, Brazil, , was evaluated. All the plants were geographically referenced with a GPS receptor. Observations were made monthly during 13 months (June, 2005 to July, 2006) quantifying open flowers and fruits produced in the intervals between the observations. It was possible suggest high conversion of flowers in fruits. The Spearman rank correlation showed positive correlation of flower number with precipitation and relative humidity. Fruit number was not correlated with the environmental variables.

Genetic structure of natural Eugenia dysenterica DC (Myrtaceae) populations in northeastern Goiás, Brazil, accessed by morphological traits and RAPD markers

The Brazilian Cerrado (Savannah) is a biome with great biodiversity. Many of the species found in this biome have unlimited economic potential and are used by the local population for various purposes. With the opening of the agricultural frontiers in this region, much of the native flora has been replaced by extensive areas of monocultures. Thirteen populations of the Eugenia dysenterica DC species were sampled in the northeast of the state of Goiás, Brazil, to analyze their genetic structure. Morphological traits were measured for all the progeny obtained and some of them were analyzed by using RAPD markers. The natural populations of the species showed high levels of variability for the morphological traits. The phenotypic, genotypic and genetic variabilities as structured in these populations were highly significant among populations, although most of the variability was detected within populations. The phenotypic and genetic variabilities were structured spatially as shown by the positive and highly significant correlation coefficients between the phenotypic and genetic distance matrixes and the geographic distance matrix. The ideal conservation strategy for the species in the region requires sampling of a high number of individuals of each population and also a significant number of populations to ensure suitable effective population sizes.

Genetic structure and gene flow in Eugenia dysenterica DC in the Brazilian Cerrado utilizing SSR markers

The ''cagaita tree'' (Eugenia dysenterica) is a plant found widespread in the Brazilian Cerrado. Its fruit is used for popular consumption and for industrial purposes. This study opens a new perspective for the generation of population genetic data and parameters estimates for devising sound collection and conservation procedures for Eugenia dysenterica. A battery of 356 primer pairs developed for Eucalyptus spp. was tested on the ''cagaita tree''. Only 10 primer pairs were found to be transferable between the two species. Using a polyacrilamide gel, an average of 10.4 alleles per locus was detected, in a sample of 116 individuals from 10 natural ''cagaita tree'' populations. Seven polymorphic loci allowed estimation of genetic parameters, including expected average heterozygosity He = 0,442, among population diversity, R ST = 0,268 and gene flow Nm = 0,680. Results indicated a potential of SSR locus transferability developed for Eucalyptus to other species of different genera, such as in the case of the ''cagaita tree''. The high genetic diversity among populations detected with SSR markers indicated that these markers are highly sensitive to detect population structure. Estimated Nm values and the existence of private alleles indicated reduced gene flow and consequently possible damage to the metapopulation structure.