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81.
浸虫法测定5种农药对甘蓝蚜的室内毒力 总被引:3,自引:0,他引:3
通过采用浸虫法,对甘蓝蚜室内毒力测定结果表明,阿维菌素、吡虫啉、毒死蜱、苏云菌.薄荷10%乳油和苏云菌.薄荷3%乳油,处理24h后LD50分别为0.962 1、2.103 6、9.442 1、996.397和2 283.659 2;处理48h后LD50分别为0.005 1、0.018 3、0.274 9、86.465 1和91.725 6;处理72h后LD50分别0.000 3、0.001 3、0.024 6、0.741 0和24.804 4。 相似文献
82.
对按月采自海州湾至莱州湾的987尾鲻进行了生物学测定,以鳞片作年龄鉴定依据,研究了鲻的年轮形成时期,体长与鳞长的相关、体长与体重的关系及鲻性成熟年龄。 相似文献
83.
黄钩蛱蝶是药用植物葎草的重要食叶害虫.在南昌一年发生5代为主,部分6代,少数7代,世代重迭,以未交配的成虫过冬.10月初羽化的成虫,当年不再交配和产卵,故越冬成虫即包含了五六七代成虫.受高温干旱的影响,夏季和秋初雌虫的产卵量及卵的孵化率明显低于春季和夏初.因此五六月份为全年发生的为害烈期. 相似文献
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海南禾本科一新记录种,洋野黍(Panicum dichotomiflorum Michx),分布于儋州、陵水、三亚、保亭、琼海。 相似文献
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87.
《Journal Of Applied Aquaculture》2013,25(3-4):191-195
Abstract Resistance of juvenile cobia, Rachycentron canadum, to low salinity, low temperature and high nitrite concentrations was examined under laboratory conditions. After acclimating juveniles to a salinity of 20 g/L (27.3°C), salinity was decreased by 2 g/L/day. The first fish died at a salinity of 8 g/L and 80% offish were dead within 24 hours of exposure to 2 g/L. Acclimation offish to 22.6°C (21 g/L salinity) followed by a temperature reduction of 0.53°C/day resulted in initial mortality at 12.9°C. The median-lethal temperature was 12.1°C and all fish were dead by the time the temperature reached 10.4°C. Fish exposed for 96 hours to nominal ? 32 mg/L nitrite-N survived. Results of this study indicate that cobia juveniles require a salinity and temperature of > 8.0 g/L and > 12.9°C, respectively, and that environmental nitrite should not be deleterious at concentrations normally found in aquaculture systems. 相似文献
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89.
Effects of dietary manganese sources and levels on growth performance,relative manganese bioavailability,antioxidant activities and tissue mineral content of juvenile cobia (Rachycentron canadum L)
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Jia‐quan Nie Xiao‐hui Dong Bei‐ping Tan Shu‐yan Chi Qi‐hui Yang Hong‐yu Liu Zhang Shuang 《Aquaculture Research》2016,47(5):1402-1412
This study was conducted to compare the effects of manganese sulphate (Mn‐S), glycine manganese(Mn‐Gly) and manganese 2‐hydroxy‐4‐(methylthio)butyrate (Mn‐HMB) on juvenile cobia, Rachycentron canadum L. Treatments consisted of 0, 2, 4, 8, 16 or 32 mg supplemental Mn kg?1 from Mn‐S, Mn‐Gly or Mn‐MHB. Growth performance, manganese status, antioxidant activities and tissue mineral content were analysed after a 70‐day feeding period. Specific growth rate (SGR) increased with feeding 6.29 to 12.65 mg Mn kg?1 diet from the Mn‐S or 6.86 to 12.39 mg Mn kg?1 from the Mn‐Gly or 6.50 to 8.33 mg Mn kg?1 from the Mn‐HMB and then plateaued above these levels. Feed conversion ratio (FCR) show decreasing first and then increased trend. Survival rate (SR) were not affected by the dietary treatments (P > 0.05). Fish fed diets supplemented with manganese at levels of 4–32 mg Mn kg?1 had obviously higher hepatic Mn‐SOD activity (P < 0.05); on the contrary, hepatic has lower malondialdehyde (MDA) content (P < 0.05) than fish fed the basal diet. The manganese concentrations of whole body and vertebrae increased with increasing dietary Mn levels from 2–32 mg Mn kg?1 (independent on manganese sources). Dietary Mn supplementation did not significantly influence the copper concentrations of whole body and vertebrae, the zinc concentrations of whole body and liver. Analysis by the broken‐line regression of SGR indicated that the optimal dietary Mn requirements in juvenile cobia were 15.42, 11.22 and 10.50 mg Mn kg?1 diet from Mn‐S, Mn‐Gly or Mn‐HMB respectively. 相似文献
90.