Tolerance of juvenile black sea bass Centropristis striata to acute ammonia and nitrite exposure at various salinities

ABSTRACT:   Experiments were conducted to determine the acute tolerance of juvenile (mean weight ± standard error, 9.9 ± 0.9 g) black sea bass Centropristis striata to environmental un-ionized ammonia-nitrogen (NH₃-N) and nitrite-nitrogen (NO₂-N) exposure at various salinities. Specifically, median lethal concentrations (LC50 values) of NH₃-N and NO₂-N at 24, 48 and 96 h of exposure were determined at salinities of 10, 20 and 30 g/L at 22°C. With the exception of LC50 values determined at 48 h, median lethal concentrations of NH₃-N to black sea bass were not influenced by environmental salinity; 24, 48, and 96 h LC50 values ranged from 0.81 to 0.85, 0.65–0.77, and 0.46–0.54 mg-NH₃-N/L, respectively. In contrast, tolerance of black sea bass to environmental NO₂-N was compromised at reduced salinities. Median lethal concentrations of NO₂-N to fish at 24, 48 and 96 h of exposure ranged from 288.3 to 429.0, 258.4 to 358.8 and 190.0 to 241.9 mg-NO₂-N/L, respectively. Results indicate that while juvenile black sea bass are relatively sensitive to acute NH₃-N exposure, they are highly resistant to NO₂-N exposure.     

甘露青鱼肌肉营养分析和评价

取材太湖流域无锡甘露水产公司养殖的大青鱼,采用化学及仪器分析手段,对青鱼含肉率及肌肉营养成分进行了分析测定,含肉率为71 08%,肌肉中蛋白质含量为16 56%,脂肪含量为14 08%,其中70 73%为不饱和脂肪酸,18种氨基酸总量为14 91%,8种人体必需氨基酸的含量为6 07%,4种鲜味氨基酸的含量为5 62%,还含有多种微量元素,通过大量基础数据综合评价甘露青鱼的营养价值。     

Impact of novel endophytes in perennial ryegrass on herbage production and insect pests from pastures under dairy cow grazing in northern New Zealand

Perennial ryegrass (Lolium perenne L.) infected with a novel endophyte (AR37 or AR1), Wild‐type endophyte or no endophyte (Nil) was sown with white clover (Trifolium repens L.) in autumn 2005. The pastures were rotationally grazed by dairy cows from 2005–2009. Annual dry matter (DM) yield did not differ but AR37 pastures had a higher ryegrass tiller density, especially after the 2008 summer drought (+130%), and less white clover than did AR1 pastures. Concentrations of alkaloids produced by the Wild‐type association (lolitrem B, ergovaline) followed the same seasonal trends as did the AR37 alkaloids (epoxy‐janthitrems) but summer drought reduced concentrations of lolitrem B and epoxy‐janthitrems to less than half the mid‐summer (February) peak concentrations in the other years. Insect pests were monitored annually between 2006 and 2009. Tiller damage by Argentine stem weevil (Listronotus bonariensis (Kuschel)) was significantly reduced by all endophyte treatments. African black beetle (Heteronychus arator (F.)) populations in soil samples increased during the experiment with Nil > AR1 > Wild‐type = AR37. Root aphid (Aploneura lentisci (Pass.)) infestations followed the pattern AR1 > Nil > Wild‐type = AR37. A lower pest pressure from all insect pests in AR37 pastures is likely to have contributed to this treatment having the highest ryegrass tiller densities.     

千岛湖茶区红茶生产发展的实践与思考

本文通过对淳安千岛湖茶区红茶生产现状的分析及红茶生产工作中的实践,提出了下一步调整茶类产品结构,实施“绿＋红”战略,利用鸠坑种资源优势,进一步推进名优绿茶、红茶共同发展,实现千岛湖茶区茶产业的第二次飞跃.     

茗科1号和金牡丹工夫红茶游离氨基酸组成特征分析

采用氨基酸自动分析仪测定分析了茗科1号和金牡丹工夫红茶游离氨基酸组分,结果表明：茗科1号工夫红茶游离氨基酸总量为38.43 mg/g,金牡丹工夫红茶为37.20 mg/g。含量较高的氨基酸组分为茶氨酸、谷氨酸、天冬氨酸、丝氨酸,其中茗科1号工夫红茶茶氨酸比例为（73.02±3.63）%,金牡丹工夫红茶茶氨酸比例为（66.82±7.94）%。茗科1号和金牡丹工夫红茶的氨基酸组分含量总体差异较小,与铁观音工夫红茶均有较大差异。通过主成分分析结果表明,丙氨酸、苏氨酸、丝氨酸和赖氨酸可以作为金牡丹工夫红茶区分茗科1号、铁观音工夫红茶的氨基酸特征组分;半胱氨酸、天冬氨酸及酪氨酸可以作为茗科1号工夫红茶区分金牡丹、铁观音工夫红茶的氨基酸特征组分。     

不同制粉方式对运黑161全麦粉加工特性的影响

为探讨不同制粉方式及不同粒度对黑小麦流变学特性及加工品质的影响,将运黑161黑小麦经直接粉碎法和回添法制得的全麦粉分别过80、100、120目筛,以运黑161黑小麦面粉为对照,分析全麦粉淀粉含量、水合特性、发酵特性以及流变学特性。结果表明,直接粉碎且过80目筛的全麦粉支链淀粉含量最高,为80.18%,破损淀粉含量最低,为9.93%,溶解度、膨润力最小,分别为2.5%和3%。回添法制备的全麦粉面团发酵高度、持气率小于直接粉碎法。直接粉碎且过80目筛全麦粉的粉质质量指数最高,为59.5,形成时间和稳定时间分别为3.45和3.2 min,较接近于黑小麦面粉,且该全麦粉的阻力值、最大阻力值在醒发时间135 min时最大,用该全麦粉制作的面包感官得分最高。综上,以直接粉碎且过80目筛制备的全麦粉为原料制作的全麦面包品质较好。本研究结果为黑小麦全麦面包研发提供了理论基础。     

Soil Organic Carbon,Black Carbon,and Enzyme Activity Under Long- Term Fertilization

The present study aims to understand the effects of long-term fertilization on soil organic carbon （SOC）, black carbon （BC）, enzyme activity, and the relationships among these parameters. Paddy field was continuously fertilized over 30 yr with nine different fertilizer treatments including N, P, K, NP, NK, NPK, 2NPK （two-fold NPK）, NPK＋manure （NPKM）, and CK （no fertilization）, N, 90 kg urea-N ha^-1 yr^-1; P, 45 kg triple superphosphate-P205 ha^-1 yr^-1; K, 75 kg potassium chloride-K20 ha^-1 yr^-1; and pig manure, 22 500 kg ha^-1 yr^-1. Soil samples were collected and determined for SOC, BC content, and enzyme activity. The results showed that the SOC in the NPKM treatment was significantly higher than those in the K, P, and CK treatments. The lowest SOC content was found in the CK treatment. SOC content was similar in the N, NP, NK, NPK, 2NPK, and NPKM treatments. There was no significant difference in BC content among different treatments. The BC-to-SOC ratios （BC/SOC） ranged from 0.50 to 0.63, suggesting that BC might originate from the same source. Regarding enzyme activity, NPK treatment had higher urease activity than NPKM treatment. The urease activity of NPKM treatment was significantly higher than that of 2NPK, NP, N, P, K, CK, and NPKM treatment which produced higher activities of acid phosphatase, catalase, and invertase than all other treatments. Our results indicated that long-term fertilization did not significantly affect BC content. Concurrent application of manure and mineral fertilizers increased SOC content and significantly enhanced soil enzyme activities. Correlation analysis showed that catalase activity was significantly associated with invertase activity, but SOC, BC, and enzyme activity levels were not significantly correlated with one another. No significant correlations were observed between BC and soil enzymes. It is unknown whether soil enzymes play a role in the decomposition of BC.     

常规优质稻品种比较试验

为筛选适宜宁化县种植的高产、优质、高效的常规稻优良品种,引进5个常规优质稻品种与当地种植面积较大的5个杂优品种进行品比试验,以谷优929作对照品种,结果表明：金农丝苗、合美占、合丰占3个品种的产量与对照品种差异不显著,综合表现较好,可进一步试种.     

夏黑葡萄控产优质高效栽培技术

夏黑葡萄在福建省葡萄主产区福安市引种栽培,通过实施双十字“水槽”型的整形修剪、小拱棚避雨栽培、控产提质的花果管理、科学肥水管理和病虫防控等配套栽培技术,种植第2年每667 m2产量536.5 kg,第3年产量1332 kg,利润上万元,经济效益十分显著.     

皮蛋加工辅料的作用及新工艺配方研究

研究了皮蛋加工中使用的红茶末、氯化钠、生石灰3种辅料的作用.结果表明,红茶末能提高料液中金属离子的浓度,控制蛋内碱度的变化,其作用可以被杜仲碎末替代;氯化钠没有实际作用,所以加工中可以用氯化钾代替,从而提高皮蛋的钾钠比;生石灰没有实际作用,可不用.试验得到最佳料液比是每100 mL水加入氢氧化钠5 g、氯化钾1 g、五水硫酸铜0.3 g、杜仲(碎末)9g,浸泡期为30 d,后熟期为30d,所得皮蛋与传统用红茶末加工的皮蛋无感官和味道差异,还使皮蛋产生了一定的保健功效.