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1.
控制sch单养雄蚕品种雌雄蚕孵出比例的催青处理因素研究 总被引:1,自引:1,他引:0
研究结果表明 :在RH 6 0 %状态下 ,控制性比的温度和下限时间负相关达到显著水平 ;控制性比的高温处理适于干燥状态下进行 ;处理后雌蚕孵化整齐度明显低于雄蚕孵化整齐度 ,雌雄蚕孵化整齐度均随处理温度的升高而下降 ,尤以雌蚕更为明显。由此提出了在RH 6 0 %状态下sch单养雄蚕品种控制性比的起点温度及温度、时间范围。认为高温催青用下限温度配合 1日收蚁法效果好 ,高温处理以后的胚胎适于在RH 80 %~ 85 %的湿度中保护 相似文献
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Peculiarities of reproduction, early ontogeny, methods of egg incubation, and influence of temperature on development are compared in wolffish (Anarhichas lupus L.) and in salmonids, mainly Atlantic salmon (Salmo salar L.). Reproductive indices of females are similar in both species, but differ in males due to the small production of sperm in wolffish, a difference explained by internal fertilization in the latter species. The rate of embryonal development until the beginning of differentiation of fin fold at the same temperature is similar in both species, but the period from activation to hatching is more than twice as long in wolffish as in Atlantic salmon. Wolffish hatch at a more advanced stage with a small remnant of yolk sac and begin to feed shortly thereafter. As in Atlantic salmon, eggs and larvae of wolffish have a wide range of temperature resistance except before and after hatching. Based on the difference of life cycles in wolffish and salmon, technologies for their artificial breeding are compared. 相似文献
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Embryonic development of common wolffish (Anarhichas lupus L.) was studied at constant temperatures 5.0, 7.0, 9.0, 11.0, 13.0 and 15.0°C. Duration of development from egg activation to several morphological stages including 50% hatching was determined. At 5.0–11.0°C, the survival rate of eggs to hatching ranged from 51 to 88% with a tendency to increase at 5.0 and 7.0°C. Morphological anomalies, bacterial contamination and large mortalities were observed in eggs incubated at 13.0 and 15.0°C. The period of hatching lasted from 10 to 50 d in different egg groups. Embryo length and yolk sac volume at identical morphological stages of development showed only slight relation to temperature. At lower temperatures newly hatched larvae were longer and at more advanced stages of ontogeny. Normal numbers of fin rays in larvae (mean values 74 for dorsal fin and 46 for anal fin) were observed at 5.0 and 7.0°C and in most larvae at 9.0°C. At 11.0 and 13.0°C, many rays were absent, with mean values for dorsal fin 60 and 39 respectively and for anal fin 28 and 4 respectively. The approximate upper limit for normal development of fin rays appeared to be 9.0 °C. 相似文献
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Damien A. Fordham Arthur Georges Ben Corey 《Aquaculture (Amsterdam, Netherlands)》2007,270(1-4):105-114
Incubation of northern snake-necked turtle (Chelodina rugosa) eggs and subsequent sale of hatchlings for the pet industry has the potential to provide culturally suitable employment for indigenous communities in northern Australia. Developmental arrest in response to egg inundation is unique to C. rugosa. Eggs can be stored under water for up to 10 weeks without appreciable impact on egg or embryo survival, allowing the transport and sale of eggs into niche markets without high levels of mortality, and permitting eggs to accumulate in diapause until there are sufficient numbers to incubate as batches. Eggs that are not inundated or inundated for short periods experience similar survival rates to eggs inundated for lengthy periods. Incubation temperature influences embryo survival and development period in C. rugosa. Embryonic survival is greatest at 26 °C, steadily declining as temperature increases to 32 °C. A similar increase in incubation temperature decreases incubation period by approximately 40 days, however almost half of this variation is attributed to the increase in incubation temperature from 26 to 28 °C. Hatchling growth in C. rugosa is characterized by two phases. There is an initial phase of relatively slow growth under the partial influence of initial egg size and incubation duration, followed by a second phase of relatively rapid growth under the partial influence of water temperature and mass at hatching. Post-hatching survival is negatively correlated with duration of egg inundation and water temperature. Evidence suggests that inundation of C. rugosa eggs for 6 weeks, incubation of embryos at 28 °C and raising hatchlings in 28 °C water will yield the best overall outcomes. 相似文献
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Identifying the transformation process of amino acid enantiomers was essential to probe into the fate, turnover and aging of soil nitrogen due to their important roles in the biogeochemical cycling. If this can be achieved by differentiating between the newly biosynthesized and the inherent compounds in soil, then the isotope tracer method can be considered most valid. We thereby developed a gas chromatography/mass spectrometry (GC/MS) method to trace the 15N or 13C isotope incorporation into soil amino acid enantiomers after being incubated with 15NH4+ or U-13C-glucose substrates. The most significant fragments (F) as well as the related minor ions were monitored by the full scan mode and the isotope enrichment in amino acids was estimated by calculating the atom percentage excess (APE). 15NH4+ incorporation was evaluated according to the relative abundance increase of m/z F+1 to F for neutral and acidic amino acids and F+2 to F (mass 439) for lysine. The assessment of 13C enrichment in soil amino acids was more complicated than that of 15N due to multi-carbon atoms in amino acid molecules. The abundance ratio increment of m/z F+n to F (n is the original skeleton carbon number in each fragment) indicated the direct conversion from the added glucose to amino acids, but the total isotope incorporation from the added 13C can only be calculated according to all target isotope fragments, i.e. the abundance ratio increment summation from m/z (Fa+1) through m/z (Fa+T) represented the total incorporation of the added 13C (Fa is the fragment containing all original skeleton carbons and T is the carbon number in the amino acid molecule). This method has a great advantage especially for the evaluation of high-abundance isotope enrichment in organic compounds compared with GC/C/IRMS. And in principle, this technique is also valid for amino acids besides enantiomers if stereoisomers are not concerned. Our assessment approach could shine a light on investigating the biochemical mechanism of microbial transformation of N and C in soils of terrestrial ecosystem. 相似文献
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Understanding carbon dynamics in soil is the key to managing soil organic matter. Our objective was to quantify the carbon dynamics in microcosm experiments with soils from long-term rye and maize monocultures using natural 13C abundance. Microcosms with undisturbed soil columns from the surface soil (0-25 cm) and subsoil (25-50 cm) of plots cultivated with rye (C3-plant) since 1878 and maize (C4-plant) since 1961 with and without NPK fertilization from the long-term experiment ‘Ewiger Roggen’ in Halle, Germany, were incubated for 230 days at 8 °C and irrigated with 2 mm 10−2 M CaCl2 per day. Younger, C4-derived and older, C3-derived percentages of soil organic carbon (SOC), dissolved organic carbon (DOC), microbial biomass (Cmic) and CO2 from heterothropic respiration were determined by natural 13C abundance. The percentage of maize-derived carbon was highest in CO2 (42-79%), followed by Cmic (23-46%), DOC (5-30%) and SOC (5-14%) in the surface soils and subsoils of the maize plots. The percentage of maize-derived C was higher for the NPK plot than for the unfertilized plot and higher for the surface soils than for the subsoils. Specific production rates of DOC, CO2-C and Cmic from the maize-derived SOC were 0.06-0.08% for DOC, 1.6-2.6% for CO2-C and 1.9-2.7% for Cmic, respectively, and specific production rates from rye-derived SOC of the continuous maize plot were 0.03-0.05% for DOC, 0.1-0.2% for CO2-C and 0.3-0.5% for Cmic. NPK fertilization did not affect the specific production rates. Strong correlations were found between C4-derived Cmic and C4-derived SOC, DOC and CO2-C (r≥0.90), whereas the relationship between C3-derived Cmic and C3-derived SOC, DOC and CO2-C was not as pronounced (r≤0.67). The results stress the different importance of former (older than 40 years) and recent (younger than 40 years) litter C inputs for the formation of different C pools in the soil. 相似文献
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