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Factors affecting rhizobia in the seed environment of the legumes Cajanus cajan, Centrosema pubescens, Glycine max, and Psophocarpus tetragonolobus were investigated. These included the effects of fungicides, insecticides, and herbicides on the survival and growth of rhizobia on agar and in liquid cultures. The pesticides used varied in their toxicity towards rhizobia but many fungicides and insecticides could be used in the vicinity of inoculated seeds. Certain fungicides and insecticides were shown to have little or no effect on the Rhizobium-legume symbiosis of C. cajan, C. pubescens, G. max, and P. tetragonolobus when added directly to inoculated seed. Various protective pelleting procedures were investigated including preparation of coating materials containing rock phosphates from different localities, talc, and bonemeal. These were applied to the seed in mixtures suspended in aqueous solutions of substituted celluloses, or gum arabic. Talc and Christmas Island rock phosphate both proved satisfactory, while “Cellofas” is recommended as the adhesive in this formulation. Soaking seeds before pelleting in an effort to remove anti-rhizobial substances from G. max seeds was beneficial in the case of soyabean cultivar KS437, but harmful when applied to Palmetto seeds. 相似文献
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Quang-Vuong Le Kushan Udayanga Tennakoon Faizah Metali 《Journal of Sustainable Forestry》2019,38(3):230-243
Seedlings of invasive species often exhibit superior physiological traits that facilitate their spread at early stages of invasion, although it is unclear whether these traits persist at the post-establishment stage. To determine whether mature exotic Acacia spp. possess superior traits over mature native plants, we compared foliar gas exchange and chlorophyll a fluorescence of Acacia auriculiformis and Acacia mangium coexisting with tropical heath forest tree species Buchanania arborescens and Dillenia suffruticosa in Brunei Darussalam. The CO2 assimilation rates of Acacia spp. were significantly higher than those of heath species at current prevailing conditions of ~400 ppm ambient CO2, 1,500 µmol m?2 s?1 photosynthetically active radiation and 30°C leaf temperature. The photosystem II of Acacia spp. exhibited significantly higher maximum quantum yield of primary photochemistry at comparable temperatures, and was more sensitive to an elevated temperature (42°C for 1 h). Better photosynthetic performance of Acacia spp., due to larger stomatal openings, better light harvesting efficiency, and greater plasticity in photosystem II, may enable adult Acacia trees to sustain a competitive growth advantage and suppress native tropical heath forest species. The competitive advantage maintained by Acacia spp. in post-establishment stage likely facilitates the establishment of monospecific Acacia stands in invaded heath forests. 相似文献
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Tran Nguyen Duy Khoa Suhairi Mazelan Sabri Muda Faizah Shaharom‐Harrison 《Aquaculture Research》2019,50(7):1885-1892
Asian seabass (Lates calcarifer) culture in marine cages have been developed rapidly in Malaysia. The high intensity of culture might facilitate several disease infection including caligid infestation. This study was conducted to evaluate the effect of neem oil (Azadirachta indica) against caligid parasites on seabass. The prevalence and clinical pathogen of Caligus infection has been described through a sampling of 150 fish from floating cage at different cultured periods. Acute toxic tests with different concentrations of neem oil were carried out on the parasite and fish host. Results revealed that the 96‐hr median lethal concentration (LC50) of Caligus and fish (10.3 ± 2.5 g of body weight) were 2 and 20 ppm respectively. The in vivo test indicated that 10 ppm of neem oil could result in 100% antiparasitic efficacy within 96 hr. These results therapeutically demonstrated the efficacy of neem oil in caligid control. 相似文献
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Conditions affecting the growth of two rhizobia (RRIM 968 isolated from Centrosema pubescens and CB 1809 from Glycine max) in the coir-dust-soil compost used in Malaysia were examined. Whilst differences in growth between the two isolates were observed, recommended conditions for rhizobial production are: compost—(coir-dust 8 g; Sungei Buloh series soil—25 g ; calcium carbonate—5 g; and distilled water—60 ml) incubation—at 25°C for 12d; storage—commercially for about 3 months at 20°C. Under these conditions more than 109 viable rhizobial cells·g?1 compost are obtainable, while more than 108·g?1 survive 5 months in storage.Addition of a “sticker” (methyl-ethyl cellulose) to the compost during incubation was encouraging. 相似文献
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Snapper had been cultured in Malaysia since 1980 due to the fry availability and the high demand. However, details on the caligids infestation were not properly documented. This study was carried out to determine the prevalence, mean intensity and site preference of Caligus rotundigenitalis (Caligidae, Siphonostomatoida) a parasitic copepod on cage cultured crimson snapper, Lutjanus erythropterus from Bukit Tambun, Penang, Malaysia. A total of 70 specimens of cultured snapper were examined based on different infestation sites such as head, body as well as operculum. The specimens were separated into three groups according to the size of the fish. C. rotundigenitalis was found to be the only species infesting L. erythropterus with the prevalence and the mean intensity of 81.4% and 5.6±4.4, respectively. There was a significant difference between the prevalence of site infestation of the body and inner operculum sites. The prevalence of C. rotundigenitalis was highest on inner operculum of the fish followed by the body and head. However, there was no significant difference in the distribution of C. rotundigenitalis over the different infestation sites derived from the three groups. The information obtained from this study can be used for more effective control measures of ectoparasitic copepod infestation in floating cages. 相似文献
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Srijaya Thekkeparambil Chandrabose Pradeep Padmaja Jayaprasad Hassan Anuar Chatterji Anil Shaharom Faizah Jeffs Andrew 《International Aquatic Research》2014,6(1):1-13
A set of feeding trials was carried out for different microalgal species and processed diets for the culture of the New Zealand pipi, Paphies australis. Five microalgal species (Isochrysis galbana clone T-ISO, Pavlova lutheri, Tetraselmis suecica, Chaetoceros muelleri, and Thalassiora pseudonana clone 3H) and three formulated diets (baker's yeast, wheat flour, and corn flour) were fed to spat, juvenile, and adult pipi for 21 days. Unfed pipi were used in the control group. The spat and juvenile pipi showed a major shell increase with I. galbana while the greatest wet weight increase was obtained with P. lutheri. The shells of adult pipi grew better with corn flour, and the P. lutheri-fed group obtained the greatest wet weight. Results of proximate analysis in adult pipi revealed that proteins and lipids were accumulated in the tissue for all fed groups, while carbohydrate levels were depleted in all treatments including the control group. It is suggested that the gonads have developed during the experiment. 相似文献
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Impact of Cuscuta australis infection on the photosynthesis of the invasive host,Mikania micrantha,under drought condition 
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下载免费PDF全文 Quang‐Vuong Le Kushan U. Tennakoon Faizah Metali Linda B.L. Lim Jay F. Bolin 《Weed Biology and Management》2015,15(4):138-146
Cuscuta species (dodders) are widespread stem holoparasites that depend on host plants for their entire mineral and water and most carbohydrate requirements. Dodders negatively affect host photosynthesis but precise information on their impact on hosts in the presence of environmental stress factors (i.e. drought) is little known. In a pot experiment, the leaf traits, gas exchange and chlorophyll a fluorescence of the invasive climber, Mikania micrantha, parasitized by Cuscuta australis, were investigated in order to study variations of host photosynthesis in response to parasitism and drought. The results showed that the concomitant presence of C. australis infection and drought significantly impacted the leaf traits (i.e. increased leaf dry mass content), gas exchange (i.e. decreased stomatal conductance and transpiration rates and increased water‐use efficiency) and quantum yield of chlorophyll a fluorescence of M. micrantha. The presence of a single stress factor (C. australis infection or drought), however, only significantly affected the leaf traits and gas exchange of M. micrantha. These results suggested that the combined additive effects of C. australis parasitism and drought significantly suppressed the photosynthesis of M. micrantha in relation to both stomatal and non‐stomatal limitation of host photosynthesis. This study provides insights into Cuscuta–host interactions under drought conditions in the tropics. 相似文献
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Bego?a Valdazo-González Anna Timina Alexey Scherbakov Nor Faizah Abdul-Hamid Nick J Knowles Donald P King 《Veterinary research》2013,44(1):76
Foot-and-mouth disease virus (FMDV) is a highly contagious and genetically variable virus. Sporadic introductions of this virus into FMD-free countries may cause outbreaks with devastating consequences. In 2010 and 2011, incursions of the FMDV O/SEA/Mya-98 strain, normally restricted to countries in mainland Southeast Asia, caused extensive outbreaks across East Asia. In this study, 12 full genome FMDV sequences for representative samples collected from the People’s Republic of China (PR China) including the Hong Kong Special Administrative Region (SAR), the Republic of Korea, the Democratic People’s Republic of Korea, Japan, Mongolia and The Russian Federation were generated and compared with additional contemporary sequences from viruses within this lineage. These complete genomes were 8119 to 8193 nucleotides in length and differed at 1181 sites, sharing a nucleotide identity ≥ 91.0% and an amino acid identity ≥ 96.6%. An unexpected deletion of 70 nucleotides within the 5′-untranslated region which resulted in a shorter predicted RNA stem-loop for the S-fragment was revealed in two sequences from PR China and Hong Kong SAR and five additional related samples from the region. Statistical parsimony and Bayesian phylogenetic analysis provide evidence that these outbreaks in East Asia were generated by two independent introductions of the O/SEA/Mya-98 lineage sometime between August 2008 and March 2010. The rapid emergence of these viruses from Southeast Asia highlights the importance of adopting approaches to closely monitor the spread of this lineage that now poses a threat to livestock industries in other regions. 相似文献
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A total of 140 bacterial isolates have been successfully isolated from various organs of diseased American bullfrog （Rana catesbeiana） cultured in Malaysia. The most frequently isolated bacteria was Edwardsiella spp. （46 isolates） followed by Aeromonas spp. （33 isolates）, Flavobacterium spp. （31 isolates）, and Vibrio spp. （30 isolates）. Majority of the bacterial isolates were found sensitive to furazolidone （85.0%）, chloramphenicol （85.0%）, oxolinic acid （90.0%）, florfenicol （95.0%）, and flumequine （97.5%）. On the other hand, most of the bacterial isolates were resistant to oleandomycin （77.5%） and lincomycin （87.5%）. Nitrofurantoin and flumequine can be inhibited the growth of all of Vibrio spp. whereas all isolates of Edwardsiella spp. were found sensitive to florfenicol and flumequine. Multiple antibiotic resistance （MAR） index were in range of 0.30-0.40, indicating that bacterial isolates from cultured bullfrogs may have received high risk exposure to the tested antibiotics. In addition, 90-100% of the isolates were resistant to copper, cadmium, and chromium. These results provided insight information on tolerance level of bacterial isolates from cultured bullfrogs to 21 antibiotics as well as heavy metals. 相似文献
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