Seed germination and seedling emergence of the invasive exotic species, Clausena excavata

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

Effect of the type of environmental stress on the emergence of sunflower (Helianthus annus L.), soybean (Glycine max (L.) Merril) and maize (Zea mays L.) seeds with different levels of vigor

Sowing is a critical time in the cycle of a crop and the seeds are frequently exposed to adverse conditions that may compromise the establishment of seedlings in the field. on this basis, the objective of the present study was to determine the effect of types of environmental stress on the emergence of sunflower, maize and soybean seeds with different levels of vigor. High vigor seeds were artificially aged in order to obtain medium and low vigor seeds and then they were sown in clay soil in plastic boxes and submitted to the following types of environmental stress during the germination process : 1) high temperature (35degreesC), 2) low temperature (15 or 18degreesC), 3) water excess (Psi > -0.0001 MPa), 4) water deficiency (Psi approximately equal to -1.1; -1.2 and -0.6 MPa for sunflower, maize and soybean, respectively), 5) sowing at a depth of 7 cm and 6) pathogenic infection of sunflower seeds with Alternaria helianthi, of maize seeds with Fusarium moniliforme and of soybean seeds with Colletotrichum dematium, var. truncata. The results were compared to those obtained with controls sown under optimal condition. It was concluded that: 1) the effect of seed vigor on emergence depends on the type of enviromental stress to which the seeds are exposed, 2) the stress to which the the seeds demonstrated highest sensitivity varied with species and 3) high temperature stress was the one that most impaired the emergence of the three species.

Comparative ''in vitro'' study on the susceptibility and emergence of mutants resistant to danofloxacin and ciprofloxacin among Staphylococcus aureus isolated from bovine mastitis

The antimicrobial susceptibility of danofloxacin was compared in vitro with ciprofloxacin against mastitogenic Staphylococcus aureus. Danofloxacin was more active than ciprofloxacin, showing minimal inhibitory concentrations (MIC90), minimal bactericidal concentrations (MBC90) and MBC/MIC ratio lower than those of ciprofloxacin. Ciprofloxacin-resistant mutants occurred at higher frequencies (greater than or equal to 10(-6)) than for danofloxacin (10(-9)).

Emergence of the Pointer Basis through the Dynamics of Correlations

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Evaluation of the in vitro susceptibility and emergence of mutants resistant to ciprofloxacin among multidrug resistant clinical isolates.

Two hundred and seventy-seven multidrug resistant clinical isolates [K. pneumoniae, (N = 87); E coli, (N = 30); Salmonella typhimurium (N = 100); P. aeruginosa, (N = 30); S. aureus, (N = 30)] from hospitalized patients specimens, were tested in vitro for sensitivity to Ciprofloxacin. Application of the disk diffusion test and determination of the minimal inhibitory concentration by the microdilution method indicated that, almost all isolates were sensitive to the drug. Overall, S. aureus and P. aeruginosa were the less sensitive organisms. Ciprofloxacin-resistant mutants occurred at frequencies of > or = 10(-5)/CFU.

Correlation of electrical conductivity and other vigor tests with field emergence of soybean seedlings

Seeds from six soybean cultivars (Cristalina, IAC 31-Foscarin, IAC-15, UFV-10, IAC-14 and IAS-5) and from five soybean cultivars (IAC 31-Foscarin, IAC-15, IAC-14, IAS-5 and Iguacu) were evaluated in 1993 and 1994, respectively, in terms of physiological seed quality by the mechanical damage (MD), standard germination (SG), accelerated aging (AA), electrical conductivity (EC), and seedling field emergence (FE) tests. Significant correlations were detected between SG, AA and EC and FE. However, in terms of the cultivar or the year, the degree of association among these parameters can change based on the environmental conditions of each year.

Effects of substrate and temperature on the emergence of Phacelia sp. (Boraginaceae) seedling

This study aimed to define the best substrate and temperature for the emergence of Phacelia sp. seedling, annual ornamental flower gardens. The experimental design was entirely randomized in a factorial scheme 37 (three different types of substrates: vermiculite, sand and sphagnum combined with seven temperature conditions: room temperature, constant at 20, 25, 30 and 35C, and alternated at 20-30C and 25-35C) with 4 replications of 100 seeds each. Emergence (%E) and Emergence Rate (ER) were evaluated. The means of the resulting values were then compared by the Tukey test at 5% confidence level. There was a significant interaction amongst substrates and temperatures for all analyzed variables. For seeds sown in vermiculite and sand, the seedlings had higher %E and emerged fastest at 20C, room temperature and 20-30C that did not present statistically significant data. In sphagnum, seedlings showed greater %E in the alternated at 20-30C, room temperature and 20C and emerged quickly at room temperature and 20C that did not present statistically significant data. At room temperature and 20C, the seedlings had higher %E and emerged faster in vermiculite and sand that did not present statistically significant data. At 25, 30 and 25-35C, the seedlings showed better %E and emerged fastest in sand. At 35C, the seedlings showed either in vermiculite and sand were not significantly different in their emergence, but emerged faster in sand. There was not significantly different among substrates in their emergence at 20-30C, but the seedlings emerged faster in vermiculite and sand. It was concluded that the Phacelia sp. seedlings in all substrates showed greater %E at room temperature, 20C and 20-30C. For all temperatures, the seedlings growth parameters were superior when seeds were sown in sand.

Orbit based procedure for doublets of scalar fields and the emergence of triple kinks and other defects

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

The effect of conspecific density on emergence of Lestes bipupillatus calvert, 1909 (Odonata: Lestidae)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

The interval between the emergence of pharmacologically synchronized ovarian follicular waves and ovum pickup does not significantly affect in vitro embryo production in Bos indicus, Bos taurus, and Bubalus bubalis

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

Influence of type and amount of straw cover on weed emergence

This research was undertaken during 2003-2004 growing season to evaluate the effects of type [forage sorghum hybrid Cober Exp (Sorghum bicolor x Sorghum sudanense), forage millet (Pennisetum americanum var. BN2), finger millet (Eleusine coracana), and St Lucia grass (Brachiaria brizantha)] and amount of straw cover (5.5 and 3.0 t ha(-1)) upon the emergence of Bidens pilosa, Chamaesyce spp., Amaranthus spp., and Commelina benghalensis, under field conditions of the Brazilian Cerrado, in the region of Uberlandia-MG. The control consisted additional treatment lacking the straw cover. Emergence of weed depended on the type and amount of straw cover, as well as the weed species. The lowest number of B. pilosa seedlings was found in the presence of forage sorghum straw; Chamaesyce spp. in the lack of straw; Amaranthus spp. in the presence of higher amount of forage sorghum and forage millet, and lower amounts of forage millet and Finger Millet. All the types and amounts of straw reduced the emergency of C. benghalensis, except at the lowest level of St Lucia grass and the lack of straw.

Seed weight of Xylopia aromatica (Annonaceae): quality evaluation from X-ray and seedling emergence

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