A comparative framework of the Erythrina velutina tree species in reforested land and native populations

Erythrina velutina Willd. (Fabaceae: Papillionoideae) is a pioneer species found in tropical and subtropical regions of the world that has medicinal properties and that is used in reforestation projects. This species is rare in some areas of northeastern Brazil. This study aimed to characterize and compare genetic structures of natural and restored populations of E. velutina, with a focus on the selection of tree seeds. A total of 108 individuals from five natural populations and one restored population were analyzed using ISSR markers, resulting in 407 polymorphic fragments. A high rate of polymorphism was observed in the restored population. The highest genetic variability was identified within populations (82%). Genetic bottleneck tests were significant for the Carmópolis/Rosário do Catete and Laranjeiras natural populations along with the Laranjeiras restored population. Genetic distances significantly correlated with spatial distance. Only the restored population retained unique alleles. Similarly, increased genetic distance was observed in individuals of the restored populations compared to the other populations. Observed genetic variation in both natural and restored populations of E. velutina was moderate, thus enabling selection of divergent trees from those trees supplying seeds. Environmental protection and management of these areas is necessary for the maintenance of these individuals and subsequent reproduction. We recommend suggestions for E. velutina conservation, since the restoration model adopted in this study did not promote the development of the specimens until the reproductive stage in a fashion that aims to augment the soil seed bank supply, as is suggested for pioneer species.Ribeirão Preto, S

Effect of salt stress on seed germination attributes of sunflower

The objective of this study was to evaluate the germination of sunflower seeds under different concentrations of sodium chloride at 0, 25, 50, 100, 200 and 250 Mol.m-3. The experiment was carried out with four replications of 25 seeds per treatment. The parameters evaluated were: percentage, index of speed germination, average time and average speed of germination. Treatment with highest germination was 25 Mol.m-3 (81%), and from 50 Mol.m-3 (72%) there was decreased to 250 Mol.m-3 (22%), the index of speed germination showed similar behavior. To mean time the longest germination was observed for 250 Mol.m-3 (5 days) and low for the control (3 days), the higher the presence of saline in the substrate causes lower germination speed. After analyzing the results the concentration of 25 Mol.m-3 presented better results for the variables analyzed and from 50 Mol.m-3 influences the salinity influenced negatively the germination promoting a decrease in the vigor.O objetivo deste trabalho foi avaliar a germinação de sementes de girassol sob diferentes concentrações de solução de cloreto de sódio a 0, 25, 50, 100, 200 e 250 Mol.m-3. O experimento foi montado com quatro repetições de 25 sementes por tratamento. Os parâmetros avaliados foram: porcentagem, índice de velocidade, tempo médio e velocidade média de germinação. O tratamento que obteve maior porcentagem de germinação foi o tratamento com concentração 25 Mol.m-3 (81%), sendo que a partir de 50 Mol.m-3 (72%) houve decréscimo da variável até o tratamento com 250 Mol.m-3 (22%), o índice de velocidade de germinação apresentou comportamento semelhante. Para o tempo médio o maior tempo de germinação observado foi para 250 Mol.m-3 (5 dias) e o menor para a testemunha (3 dias), e quanto maior a presença salina no meio, menor a velocidade de germinação. A concentração de 25 Mol.m-3 apresentou melhores resultados para as variáveis analisadas, sendo que a partir de 50 Mol.m-3 a salinidade influência negativamente a resposta germinativa, promovendo um decréscimo no vigor das sementes.São Cristóvão, S

Genetic diversity of Enterolobium contortisiliquum (Vell.) Morong. in the low San Francisco river by RAPD markers

Enterolobium contortisiliquum Vell. Morong (Leguminosae-Mimosoideae) is very much used in riparian forest restoration programs in the Low San Francisco River because of its fast initial growth. The objective of this work was to evaluate by RAPD molecular markers the genetic diversity of eight individuals of a remaining population of this species, in order to contribute for the definition of strategies for seed production. The individuals are situated in an area of 100ha in the riparian forest of the Low San Francisco River. DNA extraction was carried out with young and tender leaves using 2% CTAB. Twenty primers of ten arbitrary sequence bases were used. The products were separated in 0.8% agarose horizontal gel electrophoresis, stained with Ethidium Bromide and visualized with ultraviolet light. The genetic similarity among the individuals was calculated by Jaccard Similarity Coefficient and dendrograms were obtained using the UPGMA method. The mean value for genetic diversity among individuals was 49%, varying from 33% to 85%. Individuals 6 and 7 showed a high genetic similarity (67%). Therefore, their planting or direct seeding to restore riparian areas is not indicated in places near to each other. The results showed that strategies for seed collection and seedling production can be developed to assist in restoration programs.Enterolobium contortisiliquum Vell. Morong (Leguminosae-Mimosoideae) é uma espécie muito utilizada em programas de recuperação de matas ciliares no Baixo Rio São Francisco, devido ao seu rápido crescimento inicial. Assim, o objetivo deste trabalho foi avaliar, por meio de marcadores moleculares RAPD, a diversidade genética de oito indivíduos de uma população remanescente dessa espécie, visando contribuir para a definição de estratégias de coleta de sementes. Os indivíduos estão situados em uma área de 100 ha de mata ciliar do Baixo Rio São Francisco. Para a extração do DNA, pelo método CTAB 2%, foram utilizadas folhas tenras dos indivíduos. Testaram-se 20 oligonucleotídios de 10 bases de seqüência arbitrária, cujos produtos foram separados em gel de agarose 0,8%, submetidos à eletroforese horizontal, corados com brometo-de-etídio e visualizados em luz ultravioleta. A similaridade genética entre os indivíduos foi calculada pelo Coeficiente de Similaridade de Jaccard e a construção do dendrograma, realizada utilizando-se o método UPGMA. O valor médio de diversidade genética entre as matrizes foi de 49%, variando de 33 a 85%. Os indivíduos 6 e 7 apresentaram relativa proximidade genética (67%), não sendo indicado o plantio de suas mudas ou semeadura direta para recuperação de área ciliar em locais muito próximos. A partir dos resultados observados, podem-se desenvolver estratégias para a coleta de sementes e produção de mudas, auxiliando, assim, programas de restauração ambiental.Viçosa, M