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排序方式: 共有59条查询结果,搜索用时 62 毫秒
31.
A three-step sequencing batch reactor was used for nutrient (COD, NH4-PO4-P) removal from synthetic wastewater by using different carbon sources. The operation consisted of anaerobic, anoxic and oxic (An/Ax/Ox) phases with durations of 2/1/4.5 h. Different carbohydrates, glucose, lactose, sucrose, maltose and a mixture of glucose/maltose (50/50), were used as the sole carbon source in the first phase of experiments. Sludge age was kept constant at 10 days. Glucose was found to be the most suitable carbohydrate source with percent COD, NH4-N and PO4-P removals of 96%, 99% and 94%, respectively. Nutrient removals obtained with sucrose as the sole carbon source were close to those obtained with glucose. A mixture of glucose and organic acids (50/50) such as acetic, citric, propionic and butyric acid were used as carbon source in the second phase of the experiments. Maximum percent COD, NH4-N and PO4-P removals were 93%, 97% and 96%, respectively when a mixture of glucose and acetic acid (50/50) was used. Glucose-citric acid (50/50) combination also resulted in comparable nutrient removals. 相似文献
32.
L Celik O Oztürkcan T C Inal N Canacankatan L Kayrin 《Archives of Animal Nutrition》2003,57(2):127-136
The present study was initiated to determine whether dietary supplemental L-carnitine and niacin affect growth performance, carcass yield, abdominal fat and plasma L-carnitine concentration of broiler chicks. One-day-old broiler chicks (COB500) were used in the experiment. A two by two factorial arrangement was employed with two levels (0 and 50 mg/l) of supplemental L-carnitine and two levels (0 or 50 mg/l) of supplemental niacin in drinking water as main effects. Body weight gain was significantly improved by L-carnitine, or L-carnitine + niacin supplementation during the first 3 weeks. However, supplemental L-carnitine and niacin did not change body weight gain during the last 3 weeks of the experimental period. Supplemental L-carnitine significantly improved feed intake during the first 3 weeks. Supplemental L-carnitine or niacin did not influence carcass weight, carcass yield and abdominal fat weight. L-carnitine content in the plasma was significantly higher in the groups receiving supplemental L-carnitine and L-carnitine + niacin. It is concluded that dietary supplemental L-carnitine or L-carnitine + niacin could have positive effects on body weight gain and feed intake during the early stages of growing. However, supplemental L-carnitine or L-carnitine + niacin were not of benefit regarding the complete growth period. 相似文献
33.
Fikret Demirci Murat Muştu M. Bora Kaydan Selma Ülgentürk 《Journal of pest science》2011,84(3):337-342
Citrus mealybug Planococcus citri (Risso) (Hemiptera: Pseudococcidae) is one of the main pests on citrus trees. Biological control of the pest is based on
the release of hymenopterous parasitoids and coccinellid predators at present. The effectiveness of entomopathogen fungus
Isaria farinosa (Holmsk.) Fries ([Sordariomycetes: Hypocreales] (Syn: Paecilomyces farinosus), as an alternative biological control agent on citrus mealybug, was investigated using four different inoculum densities
and different relative humidities (RH). The entomopathogen caused 89.39% mortality in ovisacs, 84.07% mortality in second
larval stage, 84.53% mortality in adult females, and 78.71% mortality in first larval stage at 95% RH and at 1 × 108 conidia ml−1 inoculum concentration. Percent mortalities were between 50 and 60 in ovisac, first and second larval stage at 95% RH and
at 1 × 107 conidia ml−1. Percent mortality was decreased parallel to the decrease in humidity level and inoculum densities; however, the fungus caused
significant infection in 70% and 80% RH. These results demonstrated that the effectiveness of the entomopathogen is promising
for biocontrol of citrus mealybug. 相似文献
34.
A glasshouse study was conducted to investigate the effects of interspecific complementary and competitive root interactions and rhizosphere effects on phosphorus (P) and iron (Fe) nutrition of mixed grown chickpea (Cicer arietinum L.) and barley (Hordeum vulgare L.). In order to provide more physiological evidence on the mechanisms of interspecific facilitation, we determined phosphatase activities in plant and rhizosphere, and root ferric reducing capacity (FR), Fe-solubilizing activity (Fe-SA) and rhizosphere pH. The results of the experiment revealed that biomass yield of barley was significantly increased by associated chickpea as compared to monocultured barley, while mixed cropping caused a slight decreases in the biomass yield of chickpea. The rhizosphere was strongly acidified under chickpea and chickpea/barley mixed cropping and this acidification, in turn, increased the available P, Fe(II) and DTPA-Fe concentrations in the rhizosphere. Fe-solubilizing activity (Fe-SA) and ferric reducing (FR) capacity of the roots were higher in both species grown in mixed culture relative to their monoculture which may improve Fe nutrition of both species. Leaf acid phosphatase (APase, EC 3.1.3.2) activity was higher in both plants under mixed cropping that may improve P nutrition of barley by chickpea. 相似文献
35.
Pepper (Capsicum annuum L.) plants grown in pots were irrigated with the nutrient solutions containing 50, 75, and 100 mM NaCl or a control solution. Salinity markedly decreased plant growth. Increasing salinity levels increased stomatal resistance and sodium (Na), chloride (Cl), proline contents of the plants. Potassium (K), total‐nitrogen (N), and chlorophyll content of the plants were decreased under high salinity conditions. 相似文献
36.
The effects of Isaria farinosa (Holm.) and Beauveria bassiana (Balsamo) on adult stages of sunn pests Eurygaster integriceps Puton and Eurygaster austriaca (Schrk.) were investigated at 27±1°C, 95% r.h. and 16L:8D in the laboratory. Two concentrations, 1×106 and 1×108 conidia ml-1, were used. Mortality of inoculated and non-inoculated adults was counted at 6, 9 and 12 days after treatment. Beauveria bassiana caused higher mortality of both species than I. farinosa. Neither caused significantly high mortality at 1×106 conidia ml-1. Both were more pathogenic at 1×108 conidia ml-1 and caused more than 85% mortality 12 days post treatment. Both were more pathogenic to E. austriaca. 相似文献
37.
38.
Previous studies have shown that salicylic acid (SA) plays a role in the response of plants to salt and osmotic stresses. Therefore, an experiment was conducted to investigate the impact of exogenous salicylic acid on the growth, physiology and antioxidant activity of carrot (Daucus carota L. cv. Nantes) grown under combined stress of salinity and boron toxicity. The treatments consisted of salt (control, NaCl, and Na2SO4), boron (−B: 0 and +B: 25 mg B kg−1) and salicylic acid (−SA: 0 and +SA: 0.5 mmol SA kg−1). The diameter of the storage root was increased by NaCl salinity in the absence of B toxicity, however, it was increased by Na2SO4 salinity under B toxicity. For the storage root yield, NaCl salinity was more toxic than Na2SO4 salinity. With its role in plant growth regulation, SA application positively affected the storage root dry weight, S concentration, carotenoids and anthocyanin content and increased the total antioxidant activity (AA) of the shoot and storage root. SA application regulated proline and toxic ion (B, Cl) accumulation in the storage root and shoot. This study reports the long term effects of SA under stress conditions and reveals that SA was not as effective as in alleviating abiotic stress as reported in the literature conducted with short-term studies. That means long-term effects of SA would be significantly different from its short-term effects. 相似文献
39.
Zehra Selcuk Serap Ustaoglu Tiril Fikret Alagil Volkan Belen Mustafa Salman Sena Cenesiz Omer Hakan Muglali Feraye Berkay Yagci 《Aquaculture International》2010,18(2):213-221
An experiment was conducted to determine the effects of supplemental dietary l-carnitine, chromium picolinate (Cr-Pic) and their combination on growth performance and serum total protein, cholesterol,
triglyceride and glucose of rainbow trout (Oncorhynchus mykiss). A total of 276 rainbow trout were randomly allocated to four groups. Fish (average initial body weight = 151 ± 1.69 g)
were fed a basal diet without supplemental l-carnitine and chromium picolinate in the control group. The basal diet was supplemented with either 500 mg/kg l-carnitine, 1.6 mg/kg chromium picolinate or 500 mg/kg l-carnitine plus 1.6 mg/kg chromium picolinate for experimental groups 1 (C), 2 (Cr-Pic) and 3 (C + Cr-Pic), respectively.
Fish were fed twice a day to apparent satiation for 58 days. Weight gain, growth rate, feed consumption and feed conversion
ratio (feed/gain) were calculated for the whole period. At the end of the study, six fish were chosen randomly from each tank
to represent the experiment and frozen at −20°C for subsequent dorsal muscle analysis. The results showed no significant differences
in final body weight, weight gain or feed conversion ratio among groups. There were also no significant differences in serum
total protein, cholesterol, triglyceride or glucose concentrations among groups. Significantly higher lipid concentration
of dorsal muscle was observed in experimental groups 1 and 3. In conclusion, supplemental dietary l-carnitine, chromium picolinate and their combination have no beneficial effects on improving growth performance and feed
conversion ratio in rainbow trout. However, dietary l-carnitine slightly increased lipid concentration in dorsal muscle of rainbow trout. 相似文献
40.