激光人工陈化大曲酒的探讨

He-Ne激光处理大曲酒,使酒的乙醛、甲醇减少,乙酸乙脂、高级醇增加。取得与自然陈化相同的快速陈化效果。     

基于无人机影像的冠层光谱和结构特征监测甜菜长势

甜菜是中国北方地区重要的经济作物。快速、准确、高通量的获取甜菜的地上部和块根鲜质量、块根含糖率、叶绿素含量对甜菜生产具有重要意义。该研究采用无人机搭载数码和多光谱相机,获取甜菜叶丛快速生长期、块根及糖分增长期和糖分积累期的数码影像和多光谱影像,提取了冠层的结构特征和光谱特征。选择随机森林回归（Random Forest Regression,RFR）和偏最小二乘回归（Partial Least Squares Regression,PLSR）2种建模方法基于获取的冠层特征,构建甜菜全生育期的地上部和块根鲜质量、块根含糖率和SPAD（Soil and Plant Analyzer Development）值估算模型。研究结果表明,随机森林回归模型和偏最小二乘回归模型对地上部和块根鲜质量、含糖率都做出较好的预测,R2范围分别为0.9～0.94、0.88～0.9,rRMSE范围分别为7.6%～17%、8.8%～20%。对SPAD值的预测均较弱,R2分别为0.66和0.67。为了减小输入变量集的大小以及去掉对预测不敏感的变量,该研究采用置换重要性（Permutation Importance,PIMP）来筛选冠层光谱特征和结构特征中对预测有重要影响的变量。结果表明基于筛选出的重要性特征构建的随机森林回归模型和偏最小二乘回归模型对地上部和块根鲜质量、含糖率都做出较好的预测,R2范围分别为0.89～0.94、0.74～0.91,rRMSE范围分别为7.3%～19%、7.6%～19%。对SPAD值的预测均较弱,R2分别为0.65和0.68。进一步表明随机森林回归模型在精度上略好于偏最小二乘回归模型。同时基于PIMP筛选变量的方法在保持原有精度的同时能实现降低数据收集复杂性的目的。研究结果为基于无人机遥感技术快速、准确监测甜菜长势和估测块根类作物的根部活性物质提供了参考。     

河北省张家口黑龙山国家森林公园生态效益分析与评价

通过选择合理的评价模型,采用等价替代或等效益替代等方法,对黑龙山国家森林公园生态效益进行客观、科学地实证研究,为该森林公园可持续发展、保护与合理开发以及生态效益补偿提供科学依据。     

福尔马林防治鮸鱼Miichthys miiuy(Basilewsky)刺激隐核虫(Cryptocaryon irritans)的研究

本文采用在淡水和海水中加入不同浓度的福尔马林,进行鮸鱼刺激隐核虫防治的研究.结果发现,福尔马林质量浓度为221.3 mg/L的海水中,鮸鱼12 h内无死亡,海水福尔马林对鮸鱼12 h,24 h,48 h,72 h,96 h时的半致死浓度分别为475.6,413.8,248.1,212.7,200.7 mg/L,安全浓度为56.08 mg/L;淡水浸泡鮸鱼的半致死时间为126 min;淡水处理刺激隐核虫的半致死时间为26 min,海水福尔马林中,处理2 h和12 h的半致死浓度为62.5,23.3 mg/L.全池泼洒20～80 mg/L福尔马林可防治刺激隐核虫,淡水浸泡30 min后泼 25 mg/L福尔马林效果更佳.研究结果表明,海水和淡水福尔马林对刺激隐核虫的致死浓度处于鮸鱼安全范围之内,淡水浸泡30 min后泼洒25 mg/L福尔马林可有效防治刺激隐核虫.     

Comparative genomic insights into the taxonomy of Edwardsiella tarda isolated from different hosts: Marine,freshwater and migratory fish

Edwardsiella tarda, a Gram‐negative member of the family Enterobacteriaceae, has been isolated from many animal species worldwide, especially fish species. Its broad host range indicates the diversity in taxonomy, which attracted the attention of many researchers. Here, we added genome of E. tarda strain isolated from freshwater fish to comparative genomics study for the first time. We sequenced and assembled the genome of E. tarda ASE201307 which was isolated from freshwater Asian swamp eel. ASE201307 genome contained a single circular chromosome of 3.68M with G+C 57.09% content. Comparative genomics including SNP calling, synteny block, Core/Pan genes analysis and phylogeny analysis was conducted among ASE201307 and other Edwardsiella strains isolated from different fish species. Results of SNP analysis and synteny block demonstrated the close relative of ASE201307, FL95.01 and DT which were all isolated from freshwater fish. In further analysis heat map of dispensable genes and phylogenetic tree, all E. tarda strains were divided into two groups. One was isolated from freshwater fish and the other was isolated from marine/migratory fish. Based on all studies above, we proposed the living environment of hosts as a new taxonomic character and divided E. tarda isolated from diseased fish into freshwater group and marine/migratory group.     

枸杞岛海藻场两种大型海藻碎屑分解和沉降特征

岛礁水域海藻场是近岸海域典型的生态系统,大型海藻分解产生的碎屑是海藻场生态功能的重要基础。为探究大型海藻碎屑对海藻场生态功能潜在规模的贡献,本研究以枸杞岛海藻场孔石莼和舌状蜈蚣藻为对象,通过现场挂袋实验和室内静水沉降测试,分析了两种海藻碎屑的组分、粒径和沉降特征。结果显示,分解过程中舌状蜈蚣藻和孔石莼的碎屑密度均逐渐减小,且各自在不同分解时期无显著差异。舌状蜈蚣藻碎屑中有机C含量和有机N含量对密度变化影响不显著,孔石莼碎屑中有机C含量对密度没有显著影响,而有机N含量对密度有显著影响。孔石莼碎屑的δ¹³C和δ¹⁵N对其密度有显著影响,舌状蜈蚣藻碎屑的密度只受δ¹³C影响。两种海藻碎屑的密度都受木质素含量的显著影响,受纤维素含量的影响不显著。粒径是两种海藻碎屑沉降速度的决定性要素之一,研究表明,舌状蜈蚣藻大型碎屑(粒径>0.830 mm)、中型碎屑(0.380～0.830 mm)和小型碎屑(0.180～0.380mm)的沉降速度分别为0.016～0.023、0.008～0.015和0.004～0.005 m/s,孔石莼...     

日光温室负压自动灌溉下番茄蒸腾规律研究

针对农业生产中蔬菜栽培灌溉费水费时的现状,采用一种自制负压自动灌溉系统,将供水压力设定在负值,利用土壤自动吸水的特性,达到自动灌溉和节水的效果.在此系统灌溉下采用茎热平衡技术测定番茄植株的茎流规律,分析了茎流变化规律与环境因子之间的关系,同时分析了番茄植株不同部位茎流差异以及剪叶对番茄植株茎流的影响.结果表明,在设定灌溉系统负压为60 hPa下,温室土壤含水量基本控制在阴天20.19%、晴天18.75%左右;茎流数据表明番茄植株蒸腾与太阳辐射值呈显著正相关,适当遮阴降温可以减少植株蒸腾.实验也进一步证明了叶片是植株蒸腾的主要器官,植株底层叶片蒸腾速率相对较微弱.     

黄海北部中国对虾合理放流数量的讨论

在黄海北部放流虾的渔获量(y 百万尾)与放流数量(x 亿尾)之间有着统计学上可置信的关系,α=0.05,用 y=ax+bx~2描述,a=14.63,=0.45。最大放流量为16亿尾,最佳经济放流量为15亿尾(计数误差20%)。在目前条件下,我们认为控制放流量在11亿尾(计数准确率90%)是合理的。预测了前景,提出了可供选择的方案。     

长江径流对河口及邻近海区渔业影响的初步研究

根据对近年调查资料的分析，本文试就长江径流变化对邻近海区理化环境的影响、对河口及邻近海区的浮游动物的数量分布以及渔业的影响等方面进行了讨论。长江径流的变化关系到邻近海区温、盐度和冲淡水的分布，并且存在着较强的相关；不少经济鱼类的渔场正位于浮游动物总生物量高区，而近海浮游动物总生物量与长江径流量之间有着显著的正相关关系；径流量的变化不仅改变渔场位置，而且影响海区渔获量的变化。文中着重讨论了长江口、舟山和鱼山渔场的带鱼、鲐鲹鱼的分布，渔场形成，渔获量的大小与径流量关系．     

Dietary vitamin E requirement of sub‐adult genetically improved farmed tilapia strain of Nile tilapia (Oreochromis niloticus) reared in freshwater

A two‐factor orthogonal test was conducted to determine the dietary vitamin E (VE, dl ‐α‐tocopheryl acetate) requirement for sub‐adult GIFT strain of Nile tilapia (Oreochromis niloticus) at two lipid levels, and evaluate its effect on antioxidant responses. A basal diet containing 60 or 130 g/kg of soybean oil was supplemented with 0, 20, 40, 60, 120 and 240 mg VE/kg, respectively. Each diet was fed to three replicate groups of tilapia with initial weight (80.3 ± 0.7) g for 10 weeks. Results showed that the weight gain, feed efficiency and hepatic VE retention of fish were significantly increased by the increased VE in diets. In groups with 60 and 130 g/kg lipid, fish fed diets supplemented with VE had higher serum superoxide dismutase (SOD) and catalase activity, and lower malondialdehyde content than fish fed the VE un‐supplemented diet (p < .05). The proximate composition of fish had no significant difference in the group with 130 g/kg lipid, whereas crude lipid and ash content were significantly affected by dietary VE in the group with 60 g/kg lipid. Based on broken‐line regression analysis, dietary VE requirement to support the maximum weight gain and serum SOD were 43.2–45.8 and 66.0–76.1 mg/kg in diets with 60 and 130 g/kg lipid, respectively.