Are NORs Always Located on Homeologous Chromosomes? A FISH Investigation with rDNA and Whole Chromosome Probes in Gymnotus Fishes (Gymnotiformes)

Gymnotus (Gymnotiformes, Gymnotidae) is the most diverse known Neotropical electric knife fish genus. Cytogenetic studies in Gymnotus demonstrate a huge karyotypic diversity for this genus, with diploid numbers ranging from 34 to 54. The NOR are also variable in this genus, with both single and multiple NORs described. A common interpretation is that the single NOR pair is a primitive trait while multiple NORs are derivative. However this hypothesis has never been fully tested. In this report we checked if the NOR-bearing chromosome and the rDNA site are homeologous in different species of the genus Gymnotus: G. carapo (2n = 40, 42, 54), G. mamiraua (2n = 54), G. arapaima (2n = 44), G. sylvius (2n = 40), G. inaequilabiatus (2n = 54) and G. capanema (2n = 34), from the monophyletic group G. carapo (Gymnotidae-Gymnotiformes), as well as G. jonasi (2n = 52), belonging to the G1 group. They were analyzed with Fluorescence in situ hybridization (FISH) using 18S rDNA and whole chromosome probes of the NOR-bearing chromosome 20 (GCA20) of G. carapo (cytotype 2n = 42), obtained by Fluorescence Activated Cell Sorting. All species of the monophyletic G. carapo group show the NOR in the same single pair, confirmed by hybridization with CGA20 whole chromosome probe. In G. jonasi the NORs are multiple, and located on pairs 9, 10 and 11. In G. jonasi the GCA20 chromosome probe paints the distal half of the long arm of pair 7, which is not a NOR-bearing chromosome. Thus these rDNA sequences are not always in the homeologous chromosomes in different species thus giving no support to the hypothesis that single NOR pairs are primitive traits while multiple NORs are derived. The separation of groups of species in the genus Gymnotus proposed by phylogenies with morphologic and molecular data is supported by our cytogenetic data. © 2013 Milhomem et al.

Sustainable weed management on ornamental beds

The weed presence on ornamental beds is a main aspect that interferes with the garden maintenance, especially in tropical countries, as it causes an unpleasant effect and competes with the ornamentals. The use of herbicides is not always economically viable, besides, it causes phytotoxic effects on the ornamental plants, so the alternative to minimize this problem is the use of mulch; however, there is little information on the literature about it. Thus, the aim of this work was to evaluate the effect of rice straw mulching on the weed management of Salvia splendens beds. There were four treatments (0, 4, 6 and 8 t ha-1 of rice straw) and five replications. Brachiaria decumbens (200 plants m-2) and Amaranthus viridis (50 plants m-2) were sown in each plot in order to ensure the weed presence. The evaluation of the weed community was performed 60 days after sowing. The weeds on the plots of 0.48 m2 were identified and removed by hand and then dried in a chamber of forced air ventilation (under 703C) for the dry matter determination which later helped to calculate the phytosociological indexes like the Relative Density, Relative Frequency, Relative Dominance and the Importance Value Index. Nineteen species of weeds were identified. Among them, B. decumbens and A. viridis presented the highest Relative Importance level and the use of 8 t ha-1 of rice straw mulching helped to minimize the Relative Importance of these plants; however, the weed management with the use of rice straw was not effective.

Evaluation of ornamental grasses submitted to water stress

The work was carried out at the College of Agricultural and Veterinary Sciences of the State University of São Paulo (UNESP/FCAV), Campus of Jaboticabal, Brazil, aiming to study the tolerance response to water stress and capacity of regeneration after mowing three different ornamental grasses used in Brazilian landscaping: Imperial zoysia grass (Zoysia japonica 'Imperial'), zoysia grass (Zoysia japonica) and St. Augustine grass (Stenotaphrum secundatum). The experimental design was entirely randomized in a factorial scheme 33 (three grass species: Zoysia japonica 'Imperial', Zoysia japonica and Stenotaphrum secundatum; in three water stress conditions: under full sun, with and without irrigation, and under greenhouse conditions without irrigation) with four replications per plot. The irrigation was performed using microsprinklers with a flow of 0.28 L s-1, and the grasses of all plots were mowed monthly. The evaluations were executed monthly, before mowing the grass, in the beginning of each season, that means, in October (for Spring evaluation), January (for Summer), April (for Autumn) and July (for Winter), considering the Brazilian climate conditions. The evaluated parameters were shoot height and total dry mass. The data were submitted to the variance analysis and the means were compared by the Tukey test at 5% confidence level. The grasses grown under greenhouse conditions, without irrigation, showed higher height and lower dry mass weight averages, what possibly indicates that the plants etiolated. The grasses grown under full sun, either with or without irrigation, showed a similar plant development. The S. secundatum species showed greater tolerance to water stress in October, month that followed the longest dry period. The total dry mass was gradually reduced during the experiment for all grasses grown under greenhouse conditions without irrigation; however, a great general tolerance to water stress was observed for all grasses because all of them survived along nine months without irrigation.

Herbicide selectivity in herbaceous ornamental gardens of tagetes erecta L.

One of the major problems in landscaping in tropics is weed management. The herbaceous ornamental plant, Tagetes erecta L. (Asteraceae), is very popular for its beautiful flowers which can be used in landscape and also as cut flowers. The increase use of this plant and lack of selective herbicides led to the objective of this study to evaluate the herbicide metribuzin selectivity for this ornamental plant. The experimental design was completely randomized using four treatments (herbicide metribuzin doses: 0, 0.5, 1.0 and 1.5 L ha-1, equivalent to 0, 240, 480 and 720 g ha-1) and five replicates. The herbicide was applied over the seedling of T. erecta as pre-emergence of the weed seeds. Evaluations were performed at 7, 14, 21 and 28 days after application (DAA) by visual analysis of the toxicity symptoms over the ornamental, using the European Weed Research Council (EWRC) scale (1 to 9), where 1 is the total absence of symptoms and 9 to death plants. Polynomial regression statistical analysis was used. It was verified that, from the dose of 1.0 L ha-1, T. erecta plants died by 14 DAA, which the most of them had presented a very strong toxicity symptom; for the 0.5 L ha-1 treatment the plants had survived until 28 DAA. However, most of them already exhibited the high toxicity level, dying at 35 DAA. Thus, metribuzin was not suitable for T. erecta even at the lowest rate tested in this study.

Effect of temperature on seed germination of ornamental herbaceous perennials

Antirrhinum majus L. and Senecio douglasii DC. are herbaceous perennial ornamental plants used in landscaping. The multiplication of these plants is by seed; however, there are still doubts about the temperature that can provide higher rates and speed of germination. Thus the aim was to study the effect of temperature on seed germination of A. majus and S. douglasii. The study was conducted separately for each species. The experimental design was entirely randomized with six temperature conditions (temperature controlled constant of 20, 25, 30, 35°C and alternating temperatures of 20-30 and 25-35°C with a photoperiod of 12 hours) with four replications of 100 seeds each. Total germination percentage and germination rate were determined. The means were compared by Tukey test at 5%. For A majus the highest germination percentage was observed at 20°C that did not differ statistically from other temperatures. The highest germination rate was obtained at the temperature of 20 and 25°C. For S. douglasii seeds it was observed that the highest germination percentage and germination rate occurred at 20°C. The lower temperature showed the better percentage and germination rate for these species.

Multiple ornamental uses of Costus stenophyllus standi. & L.O. Williams

Costus stenophyllus or bamboo costus, despite its high ornamental potential, is still little known in the cut flower and ornamental plant market. The bamboo costus is a spiral ginger admired for its beautiful stems that are lined with brown colored alternating bands. This costus has rather straight and upright stems. Conical red inflorescences, which resemble the head of a snake, emerge from the base of the plants. The flowers are light yellow and emerge between the red scales on the rather long-lasting, attractive inflorescences. This study was carried out to evaluate the possibility of using these species as a garden plant, cut flower and cut stem. Thus, the characterization was made based on 28 characters of the plant, the leaves, the flower stem, the flowers, as well as season blooming characteristics and flower postharvest longevity.

Utilização do 'beta' - glucano sobre o desempemho produtivo, indicadores de estresse, perfil hematológico e sobrevivência do pacu (Piaractus mesopotamicus)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Ontogenia do trato digestório e desenvolvimento gonadal de Betta splendens: aspectos morfológicos

Pós-graduação em Aquicultura - FCAV

Geologia e potencialidade do granito Vermelho Capão Bonito (Sudoeste do Estado de São Paulo) como rocha ornamental

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Avaliação dos granitos Giallo São Francisco Real, Branco Dallas e Branco Marfim, do muncípio de Barra de São Francisco/ES para aplicação como rocha ornamental e de revestimento

Pós-graduação em Geologia Regional - IGCE

Doses de nitrogênio no desenvolvimento de girassol ornamental (Helianthus annuus L.) de vaso

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Diferentes concentrações de ferro na água, seu efeito na cultura do girassol ornamental e no desempenho de gotejador

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Alimento inerte e vivo no desempenho do mato grosso, (Hyphessobrycon eques)

Pós-graduação em Aquicultura - FCAV

Desenvolvimento e identificação de mirossatélites para pirarara - Phractocephalus hemioliopterus (Siluriformes, Pimelodidae): para análise de variabilidade genética

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Frequência alimentar e taxa de alimentação para Kinguio criado em hapa: desempenho produtivo e avaliação econômica

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)