Why are egg fertilization rates not correlated with hatching success in sea turtles?

[EN] The relative number of developing eggs is directly affected by fertilization rate, and unfertile eggs may indirectly negatively affect development of viable eggs within the nest. Thus, the number of viable eggs at laying should influence hatching success. We have studied both parameters in a nesting population of loggerhead turtles from Boavista Island (Republic of Cabo Verde). Fertility was estimated based on eggs excavated from nests within the first 96 hours after deposition. Our results confirm a high egg fertilization rate for the species, which exceeded an average of 94% fertility (95% confidence limits: 91.9 and 96.2%, N=43 nests).

Fertilization strategies for Sea Bass Dicentrarchus labrax (Linnaeus, 1758): effects of pre-incubation and duration of egg receptivity in seawater

Studying gamete biology can provide important information about a species fertilization strategy as well as their reproductive ecology. Currently, there is a lack of knowledge about how long sea bass Dicentrarchus labrax eggs can remain viable after being activated in seawater. The objectives of this study were to understand the effects of pre-incubation of fresh and overripe sea bass eggs in seawater and to determine the duration of egg receptivity. Pooled eggs (fresh and overripe) from four females were pre-incubated in seawater for 0 min (control), 0.5 min, 1 min, 3 min, 10 min and 30 min and then fertilized by pooled sperm from four males. The fresh eggs had a higher fertilization success than overripe eggs. Our results revealed a significant effect of pre-incubation time for both the fresh (P < 0.01) and overripe eggs (P < 0.01). Fertilization success of eggs significantly declined for both these treatments after 3 min of pre-incubation, which clearly indicates that sea bass eggs are able to be fertilized by sperm for up to 3 min after release into seawater. This study has particular importance for understanding fertilization strategies, reproductive potential, as well as reproductive ecology of sea bass.

Effect of fertilization and type of pruning on quality of fresh and dehydrated Stevia rebaudiana

Mestrado em Engenharia Alimentar - Instituto Superior de Agronomia - UL

Effect of diazotrophic bacterium inoculation and organic fertilization on yield of Champaka pineapple intercropped with irrigated sapota.

The purpose of this study was to evaluate the response of the Champaka pineapple to inoculation with the diazotrophic bacterium Asaia bogorensis (strain 219) when grown with organic fertilizer in an irrigated sapota orchard. Plantlets were transplanted to tubes containing a mixture of worm compost and vermiculite and inoculated with 108 bacterial cells. After five and a half months of acclimatization the plantlets were transplanted in furrows in the sapota orchard. Fertilizer was placed at the bottom of the furrows and covered with three doses (2.5; 5.0 and 7.5 L linear m−1 row) of three organic composts. The successful association of the plantlets with the diazo-trophic bacterium was confirmed by most probable number analysis before transferring to the field. Plants inoculated with strain AB219 showed the greatest initial leaf growth and produced the heaviest fruits compared to uninoculated plants. Plant growth and fruit yield increased with increasing compost dosages. The results suggested that Champaka pineapple benefited from the association of A. bogorensis (strain 219) when grown under irrigation and with organic fertilizer.

Conjoined twins in a monochorionic triplet pregnancy after in vitro fertilization: a case report

Background: Monozygotic monochorionic triplet pregnancy with conjoined twins is a very rare condition and is associated with many complications. Case: In this study, we describe a monochorionic–diamniotic triplet pregnancy after in vitro fertilization with an intracytoplasmic sperm injection. At a gestational age of 6 weeks and 4 days of pregnancy one gestational sac was observed, and at a gestational age of 12 weeks and 2 days, triplets with conjoined twins were diagnosed. After consulting with the parents, they chose fetal reduction of the conjoined twins. Selective feticide was successfully performed by radiofrequency ablation at 16 weeks of pregnancy. Unfortunately, the day after the procedure, the membrane ruptured, and 1 week later, all fetuses and placenta were spontaneously aborted. Conclusion: Monochorionic triplet pregnancy with conjoined twins is very rare. These pregnancies are associated with very serious complications. Intra cytoplasmic sperm injection increases the rate of monozygotic twinning and conjoined twins. Counseling with parents before IVF is very important.

Artificial fertilization of oocytes and sperm activation in pacu: effects of the spermatozoa:oocyte ratio, water volume, and in natura semen preservation

Objetivou-se foi avaliar a fertilização artificial e a duração da motilidade espermática em pacus com diferentes doses inseminantes, volumes de água e preservação do sêmen in natura. Foram realizados quatro experimentos para avaliação do efeito de doses inseminantes (7x10³, 7x10(4), 7x10(5), 7x10(6) e 7x10(7) espermatozoides ovócito-1) sobre a fertilização artificial dos ovócitos; do efeito do volume de água (0,5; 15,0; 30,0; 45,0 e 60,0 mL de água mL-1 de ovócitos) com doses inseminantes de 105.481 e 210.963 espermatozoides ovócito-1; do efeito de diluição do sêmen (0,005; 0,05; 0,5 e 5,0 µL de sêmen mL-1 de água) sobre a duração da motilidade espermática; e do efeito do armazenamento a 15 ºC por 9 h sobre a duração da motilidade espermática e o índice de sobrevivência espermática. Os maiores resultados obtidos foram: doses inseminantes entre 7x10³ e 7x10(7) espermatozoides ovócito-1; 15 a 60 mL de água mL-1 de ovócitos; diluição de 0.005 µL sêmen mL-1 de água e 98,65% de sobrevivência espermática até o tempo de preservação de 2h45min36s. A preservação a 15ºC por 9 horas não influencia a duração da motilidade espermática. As maiores taxas de fertilização podem ser observadas no emprego de 0,27 a 270 µL de sêmen mL-1 de ovócitos, com 15 a 60 mL de água para ativação.

Effects of the spermatozoa: oocyte ratio, water volume and water temperature on artificial fertilization and sperm activation of cascudo-preto

The objective of this study was to evaluate the effects of water volume and water temperature on the sperm motility duration and the number of spermatozoa, and the water volume on the fertilization rates of oocytes of Rhinelepis aspera. Experiments were carried out to evaluate the effect of semen dilutions (1.74×10-5, 1.74×10-4, 1.74×10-3, 1.74×10-2, 1.74×10-1 and 1.00 mL of sperm.mL-1 of water) and water temperature (5, 10, 15, 20, 25, 30, 35, 40, 45, and 50 ºC) on spermatozoa motility duration. In addition, the effects of insemination dose (7×10³, 7×10(4), 7×10(5), 7×10(6) and 7×10(7) spermatozoa.oocyte-1) and water volume (1.0, 30.0, 60.0, 90.0 and 120.0 mL water.2.0 mL-1 oocytes) on the artificial fertilization rates of oocytes were evaluated. The longest sperm motility duration were observed for the semen dilution of 1.74×10-5 mL semen.mL-1 water and in water at 5 ºC. The highest fertilization rates were obtained for insemination doses between 7.00×10³ and 1.23×10(7) spermatozoa. oocyte-1 and water volume of 28.11 mL water.2.0 mL-1 oocytes.

The influence of nitrogen fertilization on growth, yield, nitrate and oxalic acid concentration in purslane ( Portulaca oleracea )

Purslane (Portulaca oleracea) is widely used for culinary purposes throughout Mediterranean region, and the interest in this plant increased due to it being a source of bio-protective compounds, such as fatty acids and antioxidants. However, the use of purslane could be limited by accumulation of high levels of compounds harmful to human health, such as nitrate and oxalic acid. The main objective of present study was to evaluate the influence of nitrogen fertilization on growth and yield parameters and on nitrate and oxalic acid concentrations in leaves and stems. Plants of golden-leafed purslane of sativa subspecies were grown in styro-foam boxes with substrate and fertilized two times per week during four weeks with ammonium-nitrate solution (16.9% NO3--N and 17.6% NH4+-N), for testing of four nitrogen levels (0, 30, 60 and 90 kg N ha-1). Plant growth, yield, nitrate and oxalic acid concentrations were significantly affected by nitrogen application. The best quantity/quality ratio was achieved at fertilization level of 60 kg N ha-1, which gave a yield of 5.1 kg m-2 FW, while nitrate concentration was 48.98 and 43.90 mg g-1 DW in leaf and stem, respectively, and oxalic acid concentration was 1.27 and 0.55 mg g-1 DW, in leaf and stem, respectively: values which are not harmful for consumer health.

Organic and nitrogen fertilization of soil under Syrah grapevine: effects on soil chemical properties and nitrate concentration.

Viticulture is an activity of great social and economic importance in the lower-middle region of the São Francisco River valley in northeastern Brazil. In this region, the fertility of soils under vineyards is generally poor. To assess the effects of organic and nitrogen fertilization on chemical properties and nitrate concentrations in an Argissolo Vermelho-Amarelo (Typic Plinthustalf), a field experiment was carried out in Petrolina, Pernambuco, on Syrah grapevines. Treatments consisted of two rates of organic fertilizer (0 and 30 m3 ha-1) and five N rates (0, 10, 20, 40, and 80 kg ha-1), in a randomized block design arranged in split plots, with five replications. The organic fertilizer levels represented the main plots and the N levels, the subplots. The source of N was urea and the source of organic fertilizer was goat manure. Irrigation was applied through a drip system and N by fertigation. At the end of the third growing season, soil chemical properties were determined and nitrate concentration in the soil solution (extracted by porous cups) was determined. Organic fertilization increased organic matter, pH, EC, P, K, Ca, Mg, Mn, sum of bases, base saturation, and CEC, but decreased exchangeable Cu concentration in the soil by complexation of Cu in the organic matter. Organic fertilization raised the nitrate concentration in the 0.20-0.40 m soil layer, making it leachable. Nitrate concentration in the soil increased as N rates increased, up to more than 300 mg kg-1 in soil and nearly 800 mg L-1 in the soil solution, becoming prone to leaching losses.

Nitrogen and potassium fertilization on 'Caipira' and 'BRS Princesa' bananas in the Ribeira Valley.

2016

Cover Crops and Nitrogen Fertilization Effects on Nitrogen Soil Fractions under Corn Cultivation in a No-Tillage System.

ABSTRACT: The use of cover crops has recently increased and represents an essential practice for the sustainability of no-tillage systems in the Cerrado region. However, there is little information on the effects of nitrogen fertilization and cover crop use on nitrogen soil fractions. This study assessed changes in the N forms in soil cropped to cover crops prior to corn growing. The experiment consisted of a randomized complete block design arranged in split-plots with three replications. Cover crops were tested in the plots, and the N topdressing fertilization was assessed in the subplots. The following cover species were planted in succession to corn for eight years: Urochloa ruziziensis, Canavalia brasiliensis M. ex Benth, Cajanus cajan (L.) Millsp, and Sorghum bicolor (L.) Moench. After corn harvesting, the soil was sampled at depths of 0.00-0.10 and 0.10-0.20 m. The cover crops showed different effects at different soil depths. The soil cultivated with U. ruziziensis showed higher contents of total-N and particulate-N than the soil cultivated with C. cajan. Particulate-N was the most sensitive to changes in the soil management among the fractions of N assessed. The soil under N topdressing showed a lower content of available-N in the 0.10-0.20 m layer, which may be caused by the season in which the sampling was conducted or the greater uptake of the available-N by corn.

Effects of row spacing and nitrogen topdressing fertilization on the yield of upland rice in a no-tillage system.

This study aimed to evaluate the effect of row spacing and nitrogen topdressing fertilization of two materials (genotype 07SEQCL441 CL and cultivar BRS Esmeralda) on the plant height, yield components, grain yield, and quality of an upland rice crop grown in a no-tillage system. Trials were conducted for two growing seasons under field conditions in a 3 x 4 factorial, randomized, complete block design, with four replications. For each material, treatments consisted of the combination of row spacing (0.225, 0.35, and 0.45 m) with nitrogen (N) applied as topdressing (0, 50, 100, and 150 kg ha-1). The lowest row spacing (0.225 m) for genotypes 07SEQCL441 CL and BRS Esmeralda provided a higher number of tillers, number of panicles m-2, and grain yield of rice. Increasing rates of N in the topdressing improved the rice grain yield for both cultivars, but for 07SEQCL441 CL, the grain yield was positively affected only to applications up to 50 kg N ha-1. Row spacing and N rates did not affect the rice grain quality. Therefore, these results indicate that the narrowest row spacing used (0.225 m) with N fertilization as topdressing increased the rice grain yield most in the no-tillage system.

Straw and early nitrogen fertilization affect soil properties and upland rice yield.

The presence of cover crop straw and early application of total N at sowing may provide significant changes in the microbial population, reflecting on the N dynamics in the soil and in upland rice plants. This study aimed at determining the effect of the early application of nitrogen doses as mineral N and microbial biomass carbon in the soil, as well as in the activity of nitrate reductase, and grain yield of upland rice plants cultivated under notillage system (NTS). A randomized blocks design, in a split-plot scheme, with four replications, was used. The treatments consisted of N doses (0 kg ha-1, 40 kg ha-1, 80 kg ha-1 and 120 kg ha-1) and the presence or absence of U. brizantha cover straw. Maintaining the straw on the soil surface reduces the ammonium levels and increases the microbial biomass carbon content of the soil. The application of increasing doses of N in the soil provides increases in the levels of nitrate and ammonium in the soil up to 28 days after emergence. The activity of the nitrate reductase enzyme in the plants increases and the contents of ammonium and nitrate in the soil decrease with the crop development. The number of panicles and grain yield of upland rice increase with the increase of the nitrogen fertilization, but decrease in the presence of U. brizantha straw. Thus, it is recommend the use of early N fertilization in upland rice crop.