Dulcinéia de Carvalho

Taxa de cruzamento e sistema reprodutivo de uma população natural de Copaifera langsdorffii Desf. na região de Lavras (MG) por meio de isoenzimas

A natural population of the tree species Copaifera langsdorffii Desf., commonly found in Brazil, was investigated by isozyme electrophoresis, aiming to determine the outcrossing rate and mating system. The population sampled is located along a stretch of the river Capivari in an area of preservation (Riparian Forest), between the towns of Lavras and Itumirim, south of Minas Gerais State, Brazil. Samples of leaf tissue were taken from 20 adult individuals and from 400 progenies for isozyme analysis. Five enzymatic systems were evaluated in adults (24 alleles average) and progenies (29 total alleles). The mating system of this population was approached by the Hardy-Weinberg equilibrium test (HWE) where it was found that most loci of the adult individuals is in the ratios of the HWE and most loci of the progenies is out of the it. The estimate of the average multilocus (tm) and unilocus outcrossing rate (ts) was respectively 0.917 and 0.877, pointing out the existence of self-fertilization (8%) in the population studied. The results obtained by isozymes analyses indicated also that the species Copaifera langsdorffii is predominantly alogamous. The population has relatively high genetic variation making this population of C. langsdorffii a valuable source for genetic conservation. The minimum area size estimated for the in situ conservation was 5.0 ha.

Variabilidade isoenzimática em populações naturais de jacarandá paulista (Machaerium villosum Vog.)

This invention relates to compositions derived from polyolefins combined with a polymeric nucleating agent. The nucleating agent is specifically a diene-propylene copolymer.

Estrutura genética em microescala espacial de Myrcia splendens (Myrtaceae)

In fragmented ecosystems, very common in southern Minas Gerais, vegetation corridors are ecologically important elements for gene flow. Vegetation corridors in Lavras, MG, are narrow (from 3 to 6m), with secondary vegetation formed by trench colonization and they connect primary vegetation fragments. In both environments, it is common the occurrence of Myrcia splendens, which produces fruit with zoocoric dispersion. The objective of this work was to evaluate spatial genetic structure in fine-scale of Myrcia splendens (SW.) in environments with fragments and in their connections. Ten ISSR primers were used to access the genetic patterns in 168 trees distributed in five fragments and in 104 trees distributed in four vegetation corridors, totalizing 70 polymorphic loci. AMOVA revealed that most of the genetic diversities occurs within the the populations (96.49% in the fragments and 91.15% in the corridors). In the primary formations (F1 to F5) and in the corridors C1 and C2, the genotypes are randomly distributed. It was noted in C3 and C4 corridors, spatial genetic structure with positive and significant coancestry in the first distance class with Sp = 0.012 (P = 0.009) and 0.014 (P = 0.029), respectively.

Caracterização genética de Calophyllum brasiliense Camb. em duas populações de mata ciliar

Calophyllum brasiliense Camb. is a predominant species in areas with high water saturation such as the riparian forests in southern Minas Gerais State. The objective of this research was to study the genetic variability of C. brasiliense populations. Twenty individuals were sampled from two populations located in Funil Dam in Lavras-MG. Isozyme eletrophoresis analysis provided evidence of 17 alleles distributed in 8 loci, which were represented in five enzymatic systems: α-esterase, β esterase, acid phosphatase, malate dehydrogenase and transaminase oxalacetatum glutamate. The diversity indexes showed a low number of alleles per loci in both populations, pop I (1.75) and pop II (1.50). The polymorphic loci percentage (P) were 37.5% and 50% in populations I and II respectively. The mean heterozygosities were 0.119 and 0.111, while the expected was 0.131 and 0.112. The number of migrants ( ) between populations was 2.70. The estimated effective size was 18 individuals for population I, and 19 for population II.

Eletroforese de proteínas e isoenzimas em sementes de Copaifera Langsdorffii Desf. (leguminosae caesalpinioideae) envelhecidas artificialmente

A eletroforese vem sendo utilizada com a finalidade de auxiliar a avaliacao da qualidade fisiologica de sementes de especies florestais, uma vez que respostas mais rapidas podem ser obtidas usando-se marcadores isoenzimaticos. Sementes de copaiba (Copaifera langsdorffii) foram submetidas a diferentes tempos de envelhecimento artificial (0, 24, 48, 72 e 96 horas), em germinador (42 oC e 100% de UR), tendo como objetivo avaliar as possiveis mudancas nos padroes eletroforeticos de proteinas e isoenzimas, decorrentes do envelhecimento artificial. O envelhecimento artificial ocasionou reducao na germinacao e vigor de sementes de C. langsdorffii, sendo o vigor afetado mais rapidamente. Em relacao aos padroes eletroforeticos, nao houve diferenca significativa no conteudo de proteinas soluveis e de armazenamento, mas, nas enzimas esterase e peroxidase, verificou-se reducao na atividade destas, a medida que as sementes foram envelhecidas.

Estrutura genética espacial em populações naturais de Dimorphandra mollis (Fabaceae) na região norte de Minas Gerais, Brasil

O conhecimento e o entendimento da estruturacao genetica intrapopulacional sao importantes para o manejo e conservacao dos recursos geneticos florestais, bem como para avaliar os impactos da exploracao e fragmentacao e estabelecer estrategias de amostragem em populacoes naturais. O objetivo deste estudo foi determinar a estrutura genetica espacial (EGE) dentro das populacoes de Dimorphandra mollis Benth., visando gerar informacoes para a conservacao genetica in situ das populacoes naturais da especie. Dez locos aloenzimaticos foram utilizados para estimar as frequencias de 20 alelos referentes a 180 individuos, distribuidos em tres populacoes naturais (Campina Verde, Pau de Fruta e Vargem da Cruz) no norte de Minas Gerais, Brasil. A diversidade genetica media (Ĥe) para a especie foi de 0,463, considerada alta e todos os locos foram polimorficos, com media de 2,0 alelos por loco. Os genotipos de D. mollis nas populacoes Vargem da Cruz e Pau de Fruta encontram-se distribuidos espacialmente de maneira aleatoria (blog = -0,007, P = 0,171; blog = -0,004, P = 0,772, respectivamente). Por outro lado, os individuos da populacao Campina Verde apresentaram EGE positiva na menor classe de distância (F(300,m) = 0,05, P < 0,001), indicando agrupamentos de individuos aparentados. A EGE significativa nessa populacao foi confirmada pela estatistica Sp, com valor de 0,047 (P < 0,001). Fatores como a dispersao de polen e sementes restritas e o historico de perturbacao antropica dessa populacao podem ter contribuido para esse padrao de estrutura familiar dos genotipos. Os niveis de estruturacao genetica detectados nas populacoes estudadas devem ser considerados para estrategias mais eficientes de amostragem visando a conservacao genetica in situ.

Variações genéticas em populações de Eucalyptus spp. detectadas por meio de marcadores moleculares

Molecular marker technology combined with the classic breeding techniques can contribute significantly to a basic understanding of the crop and character investigated and help generate and develop improved products. The objective of this work is to utilize RAPD markers to detect and maximize the genetic variability in eucalyptus genotypes, identifying crossings favorable to a forest breeding program, aiming at multiple use. A total of 44 natural hybrid genotypes of the Eucalyptus genus, planted in northwestern Minas Gerais was analyzed. The RAPD molecular markers presented efficient discriminating power among the 44 evaluated genotypes, determining an average genetic distance among them of 54% and genetic divergence ranging from 24 to 73%. This shows that there is a wide genetic basis among the individuals analyzed, allowing a manipulation of this material in breeding programs. The genetic distance among the genotypes 5 and 9; 9 and 10; 9 and 19; 9 and 25; 9 and 33; 9 and 35; 9 and 36; 9 and 44; 10 and 33; 12 and 19; 12 and 33; 12 and 39 proved to be either greater or equal to 70%. Grouping analysis established by the UPGMA method, and the cut of 80% of the total genetic distance as a criterion allowed the formation of nine distinct groups. These groups presented an average genetic divergence superior to 60%. The highest mean of distance occurred between group I and the remaining groups, with 67%. The evaluation by RAPD molecular markers provided an indirect identification of the genetic variation of the genotypes and, in this sense, new crosses for the production of specific hybrids can be generated, increasing the genetic divergence and yield of wood products of superior quality for multiple uses in forest breeding programs.

Spatial Pattern and Fine-Scale Genetic Structure Indicating Recent Colonization of the Palm Euterpe edulis in a Brazilian Atlantic Forest Fragment

Rainforests worldwide are subject to increasing amounts of external pressure and degradation that dissect continuous species distributions into small and isolated fragments (Whitmore 1997). This spatial isolation and reduction of natural populations negatively affects the reproductive success of many tropical plants (Fuchs et al. 2003; Quesada et al. 2004). A reduction in the number of reproductive individuals in a population represents a decrease in the number of pollen/ovary donors and in the quantity of pollen deposited (Aizen and Feinsinger 1994). This may be accompanied by a decrease in the abundance of pollinators and selection for self-compatibility (Stephenson et al. 2000). Subsequently, such impacts can lead to

Reproductive biology of Protium spruceanum (Burseraceae), a dominant dioecious tree in vegetation corridors in Southeastern Brazil

We investigated the reproductive biology of Protium spruceanum (Benth.) Engler in vegetation corridors of secondary Atlantic forest in Lavras, southern Minas Gerais State, Brazil. The reproductive phenology was investigated fortnightly over a one year period. Floral biology studies involved pollen viability analysis, nectar production, stigmatic receptivity, pollen tube growth, visiting insect species and visit rates. The small, pale yellowish flowers (0.3-0.4 cm diameter) are functionally unisexual and organized in dense inflorescences (ca. 45 flowers). P. spruceanum presented annual flowering between September and November. Staminate flowers supplied a high percentage of viable pollen (90.6%) and relatively abundant nectar (x = 4.5 μL). Pistillate flowers produced only nectar to flower visitors (x = 4.0 μL). The effective pollinators were Apis mellifera and Trigona sp. (Hymenoptera, Apidae). Pollen tubes of cross-pollinated flowers were observed entering the ovaries 48 h after pollination. The fruiting season is from October to March, with a peak in November, coinciding with the rainfall peak. Ecological implications of these findings, and alternative arguments to explain the high genetic diversity at regional landscape are discussed.

Diversity and genetic structure in natural populations of Geonoma schottiana Mart (arecaceae): implications for conservation

Geonoma schottiana is an underbrush palm which is found in high densities in tropical forests. This species is known for having an asynchronous fruit producing pattern, over all seasons of the year, thus being an important food source for frugivores. This work aims to determine the diversity and spatial genetic structure of two natural populations, referred to as MC I and MC II, of which 60 individuals were sampled, in Poco Bonito Biological Reserve, Lavras, Minas Gerais state. Results of 10 polymorphic isozyme loci indicated a high genetic diversity for the species (Ĥ e = 0.428 and Ĥ o = 0.570), with an mean number of alleles per locus of 2.0. Estimates of Cockerhams coancestry coeffi cients indicated an absence of intrapopulation ( f = -0.343) and interpopulation inbreeding (F ˆ = -0.161), suggesting that on average populations are not endogamous. A high genetic divergence was found between populations ( p θˆ = 13.5%), in comparison to most tropical species (<5%). Consequently, the estimated historical gene fl ow was low ( m N ˆ = 0.40). The analysis of spatial distribution of G. schottiana genotypes in MCI revealed a random distribution of genotypes. The high genetic diversity indices found suggest that the populations in question favor in situ genetic conservation, consequently favoring the conservation of riparian environments.