Corrigendum to “Site-specific nutrient management for intensive rice cropping system in Asia” [Field Crops Res. 74 (2002) 37–66]     

A. Dobermann  C. Witt  D. Dawe  S. Abdulrachman  H.C. Gines  R. Nagarajan  S. Satawathananont  T.T. Son  P.S. Tan  G.H. Wang  N.V. Chien  V.T.K. Thoa  C.V. Phung  P. Stalin  P. Muthukrishnan  V. Ravi  M. Babu  S. Chatuporn  M. Kongchum  J. Sookthongsa  Q. Sun  R. Fu  G.C. Simbahan  M.A.A. Adviento 《Field Crops Research》2008

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Insecticidal, antifeedant and oviposition deterrent effects of the essential oil and individual compounds from leaves of Chloroxylon swietenia DC     

Kiran SR  Reddy AS  Devi PS  Reddy KJ 《Pest management science》2006,62(11):1116-1121

Essential oil from the leaves of Chloroxylon swietenia DC. was obtained by hydrodistillation and cold extraction, and the chemical composition was determined by gas chromatography and gas chromatography-mass spectrometry. The major identified components were limonene, geijerene, pregeijerene, germacrene D and trans-beta-ocimene. Laboratory bioassays of the essential oil and four constituents of essential oil isolates were evaluated for insecticidal, antifeedant and oviposition deterrent effects on tobacco cutworm, Spodoptera litura (F.). Toxicity was determined by topical application of the isolates at varying concentrations. Pure oil, geijerene and pregeijerene were found to be more toxic, with LD50 values of 28.6, 35.4 and 40.7 microg per larva respectively. Maximum feeding deterrence was noted for geijerene and pregeijerene, with DC(50) values of 82.5 and 95.1 microg cm(-2) respectively. Furthermore, pure oil, geijerene and pregeijerene displayed oviposition deterrence, even at low concentrations. These results indicate that these natural products may lead to useful, biodegradable, environmentally safe insect control agents.  相似文献   

Effect of Dietary Estradiol‐17β on the Feminization of Silver Perch,Bidyanus bidyanus (Mitchell, 1838)          下载免费PDF全文

Sulaeman  Ravi Fotedar 《Journal of the World Aquaculture Society》2017,48(3):444-452

The silver perch, Bidyanus bidyanus (Mitchell 1838), displays sexual dimorphism in size, with females reaching larger maximum size than males. In an attempt to produce all‐female populations, larvae at 30 d posthatching were fed an estradiol‐17β (E2) diet at dosages of 0, 60, and 120 mg/kg for 30 d. Histological examination of gonads revealed that all E2‐supplemented diets resulted in significantly higher (P < 0.05) feminization rates (97.22–100%) than did the control (39.69%) but with no difference between the two E2 diets (P > 0.05). Female and male gonads were observed in fish fed the 60 mg E2/kg diet. No significant differences were observed in the survival rate, weight gain, gonad weight and length, specific growth rate (SGR), or gonadosomatic indexes, except for gonad length and SGR at the end of the experiment. Although the ovary length of fish fed the 60 mg E2/kg diet was significantly shorter than that of the control groups, no abnormalities were detected. In contrast, fish fed 120 mg E2/kg grew faster than the other fish and showed sexual dimorphism. Our results suggest that supplementation of E2 at 60–120 mg/kg diet could be applied to establish all‐female populations of silver perch.  相似文献   

Participatory modelling to enhance social learning,collective action and mobilization among users of the mafungautsi forest,Zimbabwe     

Wavell Standa-Gunda  Tendayi Mutimukuru  Richard Nyirenda  Ravi Prabhu  Mandy Haggith  Jerome K Vanclay 《Small-Scale Forestry》2003,2(2):313-326

Participatory modelling can be a useful process to encourage critical examination of livelihood options and foster sustainable natural resource use through enhanced social learning, collective action and mobilization. The broom-grass group in the Mafungautsi Forest Reserve serves as a case study of the process and outcomes of such participatory modelling. Innovative group facilitation methods enhanced participation in the modelling process. The modelling process complements broader efforts to achieve higher levels of adaptive collaborative management. This work was conducted as part of the Adaptive Co-Management project of CIFOR, the Center for International Forestry Research. We are grateful to the UK’s Department for International Development (DFID) and the European Community for financial support of this project.  相似文献   

ZimFlores: A model to advise co-management of the mafungautsi forest in Zimbabwe     

Ravi Prabhu  Mandy Haggith  Happyson Mudavanhu  Robert Muetzelfeldt  Wavell Standa-Gunda  Jerome K. Vanclay 《Small-Scale Forestry》2003,2(2):185-210

ZimFlores (version 4) is the outcome of a participatory modelling process and seeks to provide a shared factual basis for exploring land-use options for the communal lands surrounding the Mafungautsi forest. The ZimFlores experience underscores the importance of a sharing a common problem and a common location in which all participants have an interest. Participatory modelling has proved an effective way to consolidate a diverse body of knowledge and make it accessible. Results demonstrate the importance of model outputs that are diagnostic, and which offer insights into the issues under consideration. Many people contributed in many ways to help realize ZimFlores. Some of the people who contributed include Elias Ayuk, Ivan Bond, Ephraim Chabayanzara, Muyeye Chambwera, Vijay Datadin, Wil de Jong, Peter Frost, James Gambiza, Jode Garbe, Peter Gondo, Emmanuel Guveya, Chiedza Gwata, John Hansell, Gideon Kamumvuri, Godwin Kowero, Dominic Kwesha, Chris Legg, Tim Lynam, Hilton Madevu, Simba Mandota, Everisto Mapedza, Frank Matose, Gutura Matoso, Chipo Mlambo, John Mudekwe, Maxwell Mukwekwerere, Dorcas Mungwari, Tendayi Mutimukuru, Mkhululi Ngwenya, Richard Nyirenda, Bill Ritchie, Lizwelabo Sibanda, Manasa Sibanda, Fergus Sinclair, Jivas Sithutha, Jasper Taylor, Michael Thomas, Zivanai Tsvuura and Steve Twomlow. We are grateful to the UK’s Department for International Development (DFID) and the European Community for financial support of this project.  相似文献   

Antioxidant activity of Botryococcus braunii extract elucidated in vitro models     

Rao AR  Sarada R  Baskaran V  Ravishankar GA 《Journal of agricultural and food chemistry》2006,54(13):4593-4599

Botryococcus braunii is a green colonial microalga that is used mainly for the production of hydrocarbons, exopolysaccharides, and carotenoids. In the present study, the antioxidant properties of acetone extracts of B. braunii were evaluated using in vitro model systems such as 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxy radical scavenging, and lipid peroxidation in human low-density lipoprotein and rat tissues. Acetone extracts of B. braunii (equivalent to 10 ppm total carotenoid) exhibited 71 and 67% antioxidant activity in DPPH and hydroxyl radical scavenging model systems, respectively. Similarly, the extract also showed 72, 71, and 70% antioxidant activity in the liver, brain, and kidney of rats. Low-density lipoprotein oxidation induced by Cu2+ ions was also protected (22, 38, and 51%) by the algal extract in a dose-dependent manner (4, 6, and 8 ppm levels of total carotenoid). Thiobarbituric acid reactive substances concentration in the blood, liver, and kidney of rats was also significantly decreased in B. braunii treated samples compared with those of control. Carotenoids (violaxanthin, astaxanthin, lutein, zeaxanthin, chlorophylls a and b, and alpha, beta-carotene) identified in the B. braunii acetone extract may be exhibiting antioxidant activity. Among the carotenoids, lutein represents more than 75% of the total carotenoids. B. braunii extract was shown to be effective for protecting biological systems against various oxidative stresses in vitro. This is the first report on the antioxidant properties of B. braunii.  相似文献   

Sunflower necrosis disease from India is caused by an ilarvirus related to Tobacco streak virus     

K. S. Ravi  A. Buttgereitt  A. S. Kitkaru  S. Deshmukh  D. E. Lesemann  S. Winter 《Plant pathology》2001,50(6):800-800

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The effect of combined Azospirillum inoculation and nitrogen fertilizer on plant growth promotion and yield response of the blanket flower Gaillardia pulchella     

Ravi S. Gadagi  P. U. Krishnaraj  J. H. Kulkarni  Tongmin Sa 《Scientia Horticulturae》2004,100(1-4):323-332

The investigation was carried out to examine the performance of Azospirillum isolates on growth and N uptake of Gaillardia pulchella with two nitrogen levels. Azospirillum strain OAD-2 inoculation significantly increased plant height, number of leaves per plant, branches per plant and total dry mass accumulation in G. pulchella than other inoculations and/or uninoculated control. The application of 150 kg N ha⁻¹ further enhanced the above plant growth parameters significantly over application of 112 kg N ha⁻¹. The N uptake of G. pulchella was enhanced due to Azospirillum strain OAD-2 inoculation, which was further augmented in the presence of nitrogen. The combination of Azospirillum strain OAD-2 and 150 kg N ha⁻¹ showed the highest N uptake at 120 DAT. Plant growth and yield parameters also increased when inoculated with the non-diazotrophic, but efficient IAA producing, Azospirillum strain OAD-57. From this investigation, it can be concluded that Azospirillum strains OAD-2 and OAD-11 can play an important role in the N nutrition of G. pulchella.  相似文献   

饲料酶制剂在动物营养中的应用--最新动态及展望   总被引：3，自引：0，他引：3  

Ravi Ravindran  何梅  赵世芳 《中国家禽》2005,27(17):1-5

1饲料酶制剂 家禽及猪饲料添加酶制剂以提高生产性能已经有许多年历史。但仅在过去的20年里，人们对酶昕作用的底物的结构及化学性质才有更好的了解，这才使针对特定的底物来调制酶制剂成为可能：在生物技术方面，特别是在发酵和微生物技术方面已有了突破性进展，这也才使最近10年里能够生产足够物美价廉的饲用酶制剂成为现实，以保证在家禽口粮中的应用。  相似文献   

How molecular methods change our views of FeLV infection and vaccination     

Hofmann-Lehmann R  Cattori V  Tandon R  Boretti FS  Meli ML  Riond B  Lutz H 《Veterinary immunology and immunopathology》2008,123(1-2):119-123

FeLV was discovered 40 years ago and vaccines have been commercially available for almost two decades. So far, most FeLV pathogenesis and vaccine studies were conducted assaying parameters, such as virus isolation and antigen detection. Accordingly, regressive infection was characterized by transient or undetectable viremia, while persistent viremia is typically observed in cats with progressive infection. Using real-time polymerase chain reaction assays, the spectrum of host response categories to FeLV infection was recently refined by investigating proviral and plasma viral RNA loads. Cats believed to be immune to FeLV infection were found to turn provirus-positive after virus exposure. Moreover, efficacious FeLV vaccines were found unable to prevent provirus-integration and minimal viral replication. Remarkably, no difference was found in initial proviral and plasma viral RNA loads between cats with different infection outcomes. Only subsequently, the infection outcome is associated with FeLV loads. FeLV provirus was found to persist for years; reoccurrence of viremia and disease development was observed in some cats. Thus, aviremic provirus-positive cats are FeLV carriers and, following reactivation, may act as an infection source. However, integrated viral DNA may also be essential for solid protection and long-lasting maintenance of protective immunity. In conclusion, real-time TaqMan PCR and RT-PCR assays are highly sensitive and specific. They yield a more sensitive measure for FeLV exposure than antigen detection, virus isolation or immunofluoresence assays. We recommend the use of real-time PCR assays to identify FeLV exposed cats, particularly in catteries, and investigate obscure clinical cases that may be FeLV-associated. The use of sensitive molecular methods will contribute to a more in-depth understanding of the FeLV pathogenesis.  相似文献