Seasonal shift in spawning of Atlantic cod (Gadus morhua L.) by photoperiod manipulation: egg quality in relation to temperature and intensive larval rearing

Commercial intensive fry production of Atlantic cod will be dependent on production of viable eggs independent of season. This can only be done by manipulation of maturation by photoperiod, but little is known about potential effects on egg characteristics and larval viability. In two cod broodstocks, maturation was successfully advanced or delayed 6 months compared with normal spawning season (March–April) by manipulation of photoperiod. The advanced broodstock spawned both in spring and autumn the same year. In two of the spawning tanks during autumn, ambient temperature was reduced after reaching 13.7°C during the first half of the spawning period. Egg quality and viability were monitored, and several egg batches were incubated, hatched and start‐fed for examination of growth and survival. Temperatures above 9.6°C resulted in significant reductions in fertilization and normal egg development. Concurrently, fractions of dead and unfertilized eggs increased with elevated temperature. Actual relative fecundity was not affected by temperature. Egg characteristics improved when temperature was controlled and lowered below 9.6°C. Occurrence of irregular spawners suggests that handling of broodstock fish should be avoided during maturation and spawning. Cod larvae originating from eggs of the advanced or delayed broodstocks were successfully reared beyond metamorphosis. Survival was 9.0–46.6% and 29.3% in green and clear water respectively. Survival correlated with both initial and average feeding conditions, but growth rate did not correlate with either of survival and feeding conditions. Specific growth rates (8.3–13.6% day⁻¹) is comparable with other intensive rearing trials with cod, but were lower than reported from nature‐like systems.     

旱作水稻水肥耦合模型及经济效应

为了探讨膜下滴灌旱作水稻水分、肥料与产量之间的关系,采用通用旋转组合设计试验方法,进行膜下滴灌旱作水稻水肥耦合模型试验,并对其应用前景进行了比较分析.在供试土壤膜下滴灌条件下,灌溉定额、氮、磷与水稻产量之间符合三元二次回归模型,其一次项、二次项及水氮交互项回归系数均达显著水平,三因素的增产作用从大到小依次为灌溉定额、施氮量、施磷量.采用此模型计算的预测产量与实际产量之间呈高度正相关,预测准确度达99%.由此计算得出最高产量灌溉定额及其施肥量、经济最佳灌溉定额及其施肥量.提出实现目标产量的水肥最优组合方案:若以9 300~9 600 kg/hm²为目标产量,则灌溉定额、氮、磷用量分别为9 730~10 500 m³/hm²,272~363 kg/hm²,136~147 kg/hm²;若同时考虑经济效益,则最佳的灌溉定额、氮、磷肥用量分别为8 500~9 015 m³/hm²,225~240 kg/hm²,90~120 kg/hm².对比不同种植模式表明,膜下滴灌旱作水稻的产量与播后上水直播基本持平,其成本与育秧移栽种植持平,但水分生产效率(1.06 kg/m³)远远高于其他3种种植方式.与传统育秧移栽种植相比较,膜下滴灌旱作水稻节水50%,节约肥料30%以上.     

肉鸡血浆VLDL浓度的选择效应——对产蛋性能的影响

以零世代和一世代高、低脂系肉鸡为素材 ,个体记录高、低脂系母鸡产蛋性能 ,屠宰测定零世代 54周龄母鸡腹脂重 (率 ) ,探讨肥度性状与产蛋性能的关系 ,并研究零世代、一世代高、低脂系产蛋性能选择效应。结果表明 :在限饲条件下 ,腹脂重 (率 )与开产日龄、产蛋量表型相关很弱。腹脂重 (率 )与蛋重呈负表型相关趋势 ;零世代高、低脂系产蛋性能差异不显著。一世代低脂系比高脂系早开产 6.7d,低脂系 4 0周龄和 54周龄产蛋量显著高于高脂系 ,表明对血浆 VLDL浓度的选择使产蛋性能产生了有益的间接反应     

Alkaloids with Cardiovascular Effects from the Marine-Derived Fungus Penicillium expansum Y32

Three new alkaloids (1, 4 and 8), together with nine known analogues (2, 3, 5–7, and 9–12), were isolated from the marine-derived fungus Penicillium expansum Y32. Their structures including the absolute configurations were elucidated by spectroscopic and Mosher’s and Marfey’s methods, along with quantum electronic circular dichroism (ECD) calculations. Each of the compounds was evaluated for cardiovascular effects in a live zebrafish model. All of the compounds showed a significant mitigative effect on bradycardia caused by astemizole (ASM) in the heart rate experiments. Compounds 4–6 and 8–12 exhibited potent vasculogenetic activity in vasculogenesis experiments. This is the first study to report that these types of compounds show cardiovascular effects in zebrafish. The results suggest that these compounds could be promising candidates for cardiovascular disease lead compounds.     

藏药角茴香属植物药学研究概况

角茴香属主要有直立角茴香（H.erectum L.）、节裂角茴香（H.leptumHook.fet Thoms.）等,使传统的藏药植物。但其药用价值、临床应用有待于进一步深入研究。在广泛文献检索基础上,笔者对中药角茴香的化学成分、药理作用及临床应用等进展作了综述,为角茴香的利用提供了参考。     

开花后水分亏缺对小麦生理影响与化学调控的补偿效应

旱棚PVC管栽培冬小麦“京冬 8号”试验研究结果表明 ,小麦开花后水分亏缺影响氚水 (3H2 O)在其根系和旗叶中动态、初生根和穗下节维管束特征、根系活力、叶片蒸腾速率、气孔阻力和14C同化物输出速率及比例。用植物生长延缓剂HK 6拌种和起身期叶面喷施处理 ,可增加初生根大导管和维管束鞘横截面积 ,提高根系活力 ,促进根系3H2 O的吸收和向地上部器官运输 ;增加穗下节大维管束横截面积 ,并可能促进水分向穗部运输 ;增加旗叶中气孔阻抗 ,维持适当水分蒸腾速率 ,缓解水分胁迫下叶片3H2 O的减少 ;提高单株水分利用效率 ,化学控制处理可缓解和补偿水分胁迫对小麦生理造成的不良影响 ,对小麦节水栽培和抗旱增产具有应用潜力     

入世对我国金融安全影响的综合分析

入世意味着我们必须遵守与贸易有关的投资措施的协议,本文分析了这一进程中对我国金融安全的积极影响和消极影响,在此基础上探讨了我们今后应改进的对策.     

超高产水稻产量形成的气候生态特点研究

在云南和湖南异地异季种植，研究了水稻超高产形成的相应气候生态条件，结果表明：超高产水稻具有大穗、多穗、高结实率的特点．云南试区具有日较差大、日照时数多、相对湿度低，平均温度较低的气候特点，故水稻生育期较长，同化物积累多，成穗率高，灌浆强度大．湖南试区阴雨寡照是影响产量的重要因素．     

内生枯草芽孢杆菌B-001对烟草幼苗的促生作用及其生长动态

为了明确内生枯草芽孢杆菌B-001对烟草的促生机制和对烟草青枯病的防治效果,采用温室盆栽试验、内源激素检测及处理烟草植株B-001菌量追踪测定等方法研究内生枯草芽孢杆菌B-001的作用机制及其自身在烟草体内的群体数量动态等。结果表明:施用B-001菌株后,烟草幼苗鲜重增加了43.01%～57.70%;烟草中吲哚乙酸、赤霉素和玉米素核苷的含量增加,而脱落酸的含量降低;苗期至旺长期的烟草K326中B-001数量大幅增加,但到成熟期数量大幅下降;1×107、1×108、1×109、1×1010cfu/mL的菌悬浮液对烟草青枯病的防治效果分别为50.3%、62.8%、70.2%、70.3%。     

Do cover crops change the lability of phosphorus in a clayey subtropical soil under different phosphate fertilizers?

Plants have developed different mechanisms to absorb and solubilize phosphorus (P) in the soil, especially in environments with low P availability. This study evaluated the effects of different winter cover crops on soil P availability in a clayey subtropical (Hapludox) soil receiving soluble P fertilizer and a rock phosphate applied to the summer crop, under no‐tillage. The experiment was carried out over 3 yrs (2009–2011) with five different cover crop species: common vetch, fodder radish, ryegrass, black oat, white clover and fallow as control. The soil was sampled after the third year of cover crop cultivation and analysed for inorganic and organic P forms according to the well‐established Hedley fractionation procedure. Phosphate fertilizers promoted accumulation of both labile and nonlabile P pools in soil in the near surface layer, especially under rock phosphate. Fertilizer applications were not able to change P fractions in deeper layers, emphasizing that the Brazilian clayey soils are a sink of P from fertilizer and its mobility is almost nil. Although the cover crops recycled a great amount of P in tissue, in a short‐term evaluation (3 yrs) they only changed the content of moderately labile P in soil, indicating that long‐term studies are needed for more conclusive results.