Retracted: Effectiveness of carp pituitary extract and luteinizing hormone releasing hormone analogue administration (by either injection or cholesterol pellet implantation) on spawning performance in female sturgeon,Huso huso          下载免费PDF全文

Mohammad Sadegh Aramli  Rajab Mohammad Nazari  Parham Farsi  Nooshin Mehdinejad  Salim Aramli  Ebrahim Sotoudeh 《Aquaculture Research》2017,48(4):1915-1922

The effectiveness of common carp pituitary extract (CPE), luteinizing hormone releasing hormone analogue (LHRH‐A₂) injections and LHRH‐A₂ implants for spawning induction in female sturgeon, Huso huso was examined. In the first trial, fish were injected with 7% physiological saline (control), 50 mg kg^?1 CPE or LHRH‐A₂ at 3.5, 7, 8 or 10 μg kg^?1. In the second trial, fish were treated with LHRH‐A₂ cholesterol pellet implants containing 0, 3.5, 7, 8 and 10 μg kg^?1 LHRH‐A₂. Ovulated eggs were removed using a minimally invasive surgical technique and were artificially fertilized. Injection of CPE and LHRH‐A₂ at doses of 3.5, 7, 8 and 10 μg kg^?1 resulted in the number of ovulated fish more than LHRH‐A₂ implants (similar doses) or controls, although there was no significant difference at doses of 8 and 10 μg kg^?1 (P ≥ 0.05). The latency period of fish receiving CPE and LHRH‐A₂ injections was approximately 20 h, which was significantly lower than in fish receiving LHRH‐A₂ implants (P ≤ 0.05). Furthermore, there were no significant differences in rates of fertilization or hatching among the progeny produced in any of the treatment groups (P ≥ 0.05). In conclusion, the data from this study could be useful for artificial propagation of not‐fully‐matured females of H. huso at sturgeon hatcheries.  相似文献   

Electrofishing in streams of low water conductivity but high biodiversity value: Challenges,limits and perspectives     

Gaetan Pottier  William R. Beaumont  Frdric Marchand  Pierre‐Yves Le Bail  Didier Azam  Jacques Rives  Rgis Vigouroux  Jean‐Marc Roussel 《Fisheries Management and Ecology》2020,27(1):52-63

Electrofishing in streams of low water conductivity has technical limitations leading to the widespread use of poison fishing. In theory, provided a high enough voltage gradient can be created in water, electrofishing should be possible in all but the lowest of conductivities (<10 µS/cm). Using custom‐made equipment delivering up to 1,500 V DC, tests were carried out in French Guiana on 27 streams with water conductivity as low as 16 µS/cm. Approximately 5,800 fish of 93 species were captured, with an electrofishing mortality rate of 1.83%. Poison treatments were used within enclosed sections to assess how efficient multiple pass electrofishing removal is when assessing species richness and population number. The Chao II estimator on 2 electrofishing passes gave the best results for species richness, but rare species can elude electrofishing. Estimates of total fish abundance (i.e. all species pooled) were possible with the use of depletion models. Capture efficiencies by species were highly biased, however, and abundance could be underestimated for the most difficult species to catch. These results show that with the right equipment and settings, electrofishing can be an efficient alternative to poison fishing surveys in small tropical streams of low water conductivity but high biodiversity value.  相似文献   

COMPARATIVE STUDY OF DIFFERENT SALTS (SODIUM CHLORIDE,SODIUM SULFATE,POTASSIUM CHLORIDE,AND POTASSIUM SULFATE) ON GROWTH OF FORAGE SPECIES     

Nayer Azam Khosh Kholgh Sima  Sara Tale Ahmad  Mohammad Pessarakli 《Journal of plant nutrition》2013,36(2):214-230

Osmotic and specific ion effects are the most frequently mentioned mechanisms by which saline substance reduces plant growth. However, the relative importance of osmotic and specific ion effect on plant growth seems to vary depending on the salt tolerance of the plant under study. Tall wheatgrass (TW), perennial ryegrass (PR), African millet (AM) and Rhodesgrass (Rh) were grown in nutrient solution with sodium chloride (NaCl), sodium sulfate (Na₂SO₄), potassium chloride (KCl), and potassium sulfate (K₂SO₄) salinity up to electrical conductivity (EC) 27 dS m^?1. Growth of all plant species decreased significantly at high level (EC 27 dS m^?1) of NaCl and Na₂SO₄ salts. However, the growth of none of the plant species was affected significantly by KCl and K₂SO₄ at any level. Even leaf and shoot fresh weights were enhanced by K₂SO₄ in all plant species, except AM. Chlorine (Cl) was taken up in similar quantities from KCl and NaCl solutions and the content of the respective cations was similar to each other. Further sensitivity to sulfate and chloride was equal when sodium concentrations in shoots were equal, regardless of the anion composition of the media. The sodium (Na) concentration of the leaves of the plant species increased with increased NaCl and Na₂SO₄ levels in the nutrient solutions. The leaf Na concentration of TW was lower than that of the other plant species. However, the root Na concentration of TW was higher than that of the other plant species. Increased NaCl and Na₂SO₄ concentrations had a marked effect on leaf water potential of all plant species, and the TW showed higher leaf water potential at all levels of salts. Tall wheatgrass adjusted osmotically by accumulating electrolytes from the nutrient solution and by accumulation of glycinebetaine. Sodium was generally found more injurious than Chloride in all the four forage species. Salt tolerance could be ascribed as greater exclusion of Na ion.  相似文献   

Effect of some pesticides on plant growth,root nodulation and chlorophyll content of chickpea     

Sartaj A. Tiyagi  Shamim Ajaz  M. F. Azam 《Archives of Agronomy and Soil Science》2013,59(6):529-533

Different concentrations, viz. 5, 10 and 25 ppm of aldicarb, carbofuran, phorate fensulfothion and fenamiphos were observed for their pesticidal effects on chickpea plant in terms of various plant growth parameters such as plant length as well as weight, pod numbers, root-nodulations and chlorophyl content. Significant improvement in plant growth was noted in lower concentrations such as 5 and 10 ppm of different pesticides but 5 ppm concentration proved highly effective and non-phytotoxic. The phytotoxic effect was noted in those plants treated with 25 ppm concentration of all the pesticides. Carbofuran was found to be most effective for improvement of over all plant growth and fensulfothion the least.  相似文献   

Intercropping with garlic alleviated continuous cropping obstacle of cucumber in plastic tunnel     

Xuemei Xiao  Huanwen Meng  Muhammad Azam Khan  Hezi Li 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(8):696-705

Abstract

Continuous cropping obstacle is prevalent for protected cultivated cucumber in China. Intercropping garlic may effectively relieve this obstacle due to its allelopathic and antimicrobial effects. A two-growing season investigation was carried out during autumn 2009 to spring 2010 in plastic tunnel to determine the effects of intercropped garlic and green garlic on the overall growth of cucumber and soil biological properties. Results showed that green garlic exhibited the inhibitory effect on the growth of cucumber in spring cultivation 2010. Garlic–cucumber intercropping system increased yield of cucumber differently depending on garlic cultivars, with only cv. G005 showing significant increase (13.4%). Intercropping systems were evaluated as a greater net benefit system as compared to monoculture cultivation. Populations of soil bacteria and actinomyces were stimulated, while fungi were inhibited under intercropping system. Activities of soil invertase, urease, and alkaline phosphatase were encouraged under intercropping system in spring cultivation 2010 compared with monoculture. The promotion effect of intercropped garlic on urease and alkaline phosphatase maintained till garlic harvest. These results suggest that intercropping system can improve soil biology environment and alleviate continuous cropping obstacle of cucumber at different levels.  相似文献   

Bacterial 5-nucleotidase in aquatic ecosystems: a novel mechanism of phosphorus regeneration     

Ammerman JW  Azam F 《Science (New York, N.Y.)》1985,227(4692):1338-1340

Zooplankton excretion and algal alkaline phosphatase are presumed to be responsible for phosphorus recycling in aquatic ecosystems; the role of bacteria has been unclear. High levels of bacterial cell-surface 5-nucleotidase were discovered in samples of picoplankton from California coastal waters. 5-Nucleotidase rapidly generated orthophosphate from 5-nucleotide added in nanomolar amounts and could supply half the orthophosphate required by plankton. Unlike alkaline phosphatase, 5-nucleotidase was not inhibited by orthophosphate at any concentration found in aquatic environments. Initial results indicate even greater 5-nucleotidase activity in fresh water (Lake Hodges, California) and brackish water (Baltic). Release and uptake of orthophosphate were tightly coupled.  相似文献   

Microbiology. Chitin, cholera, and competence     

Bartlett DH  Azam F 《Science (New York, N.Y.)》2005,310(5755):1775-1777

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The indigenous hill-farming system of Khasia tribes in moulvibazar district of Bangladesh: Status and impacts     

Narayan Saha  M. Atiqul Azam 《Small-Scale Forestry》2004,3(2):273-281

Rapid economic growth of the Khasia people has resulted from a most successful betel leaf farming system practiced within the fringe of reserved forests, where government policies have facilitated effective use of the local people as a labour force for production, protection and conservation of biodiversity of the surrounding forests. Khasia tribes have traditionally grown betel leaf plants on naturally occurring trees. Deforestation is a serious problem in Bangladesh, whereas the Khasia people living within forests are protecting trees for their livelihood, including selling betel leaf, collecting fuelwood and consuming and selling fruits from support trees. It is a profitable yet sustainable forest production system, maintaining soil fertility, stable production and optimal family size, and has created employment opportunities for the people living within and outside the forests. It has enhanced the supply of socially required betel leaf to the local markets, contributed to price stability, and generated some export revenue. However, the revenue of growers has been reduced by plant diseases and the capture of resource rent by middlemen. Economic benefits could be further increased through government initiatives to improve management and the marketing system. This paper is based on a presentation at the International Conference on Economics of Sustainable Forest Management, University of Toronto, Canada, May 20–22, 2004.  相似文献   

Effects of ammonium and nitrate on mineralization of nitrogen from leguminous residues   总被引：2，自引：0，他引：2  

F. Azam  R. L. Mulvaney  F. W. Simmons 《Biology and Fertility of Soils》1995,20(1):49-52

A laboratory incubation experiment was conducted to compare the effects of NH _inf4 ^sup+ and NO _inf3 ^sup- on mineralization of N from ¹⁵N-labelled vetch (Vicia villosa Rotn) in an Illinois Mollisol, and to determine the effect of a nitrification inhibitor (nitrapyrin) on mineralization of vetch N when used with NH _inf4 ^sup+ . The addition of either NH _inf4 ^sup+ or NO _inf3 ^sup- (100 and 200 mg N kg^-1 soil) significantly increased mineralization of vetch N during incubation for 40 days. The effect was greater with NH _inf4 ^sup+ than with NO _inf3 ^sup- , and a further increase occurred in the presence of nitrapyrin (10 mg kg^-1 soil). The addition of NO _inf3 ^sup- retarded the nitrification of NH _inf4 ^sup+ -N derived from vetch.  相似文献   

Immobilization of ammonium and nitrate and their interaction with native N in three Illinois Mollisols     

F. Azam  F. W. Simmons  R. L. Mulvaney 《Biology and Fertility of Soils》1993,15(1):50-54

Summary Three Illinois Mollisols were incubated for 2 weeks at 25°C after treatment with different amounts of glucose and/or ¹⁵N-labelled (NH₄)₂SO₄ or ¹⁵N-labelled KNO₃. The objectives were: (1) to compare the immobilization and interaction of NH _inf4 ^sup+ –N and NO _inf3 ^sup- –N with the native soil N, and (2) to study the relationship between immobilization of applied N and the added N interaction. As determined, immobilized N refers to forms not extractable with 2 MKCl (immobilized ¹⁵N+clay-fixed ¹⁵NH _inf4 ^sup+ ). In all cases, both NH _inf4 ^sup+ –N and NO _inf3 ^sup- –N were actively immobilized and transformed into organic forms in the presence of glucose. In the absence of glucose, a higher proportion of NH _inf4 ^sup+ than NO _inf3 ^sup- was recovered in organic forms. Although the three soils differed considerably in the amounts of applied N immobilized, similar trends in N immobilization were observed. A positive added N interaction occurred with all soils, the magnitude increasing with the rate of N addition. In the absence of glucose, higher added N interactions were obtained for NH _inf4 ^sup+ than NO _inf3 ^sup- , whereas there was very little difference between NH _inf4 ^sup+ and NO _inf3 ^sup- in the presence of glucose. The results indicate that under conditions of rapid immobilization (e.g., in the presence of glucose), NH _inf4 ^sup+ and NO _inf3 ^sup- will show comparable interaction with the native soil N, whereas in unamended soil, the extent of this interaction will be greater with NH _inf4 ^sup+ than with NO _inf3 ^sup- . Significant correlations were observed between applied N immobilized and the added N interaction only in one soil having a high initial mineral N content.  相似文献