大青山水源涵养林小气候观测研究

对大青山白石头沟流域内的两种主要林分 :白桦次生林和油松人工林与对照区进行了小气候对比观测 ,结果表明 :白桦林和油松林均起到了改变太阳辐射调节了近地层地表及地下温度 ,缩小温差、降低风速、减少大气蒸发 ,提高土壤及大气湿度 ,有效的截留了降水等重要生态作用 ,但白桦林的小气候环境优于油松林。     

N-氨甲酰谷氨酸在猪生产中的研究进展

N-氨甲酰谷氨酸(NCG)是精氨酸合成链中N-乙酰谷氨酸(NAG)的类似物,可替代NAG作为机体合成精氨酸的外源前体物质,在畜禽生产具有增强机体免疫能力、促进生长发育、提高繁殖性能、改善胴体品质等作用.文章结合近年国内外研究结果就NCG的主要生物学作用及其在猪生产的应用效果作一综述,以期为NCG在猪生产中的广泛应用提供...     

夏玉米冠层温度变化的时滞效应及其对土壤水分监测的影响

考虑冠层温度变化的时滞效应,可能在一定程度上能够提高土壤含水率的监测精度.该研究以灌浆期的夏玉米为研究对象,利用精密红外温度传感器(SI-411)连续监测I1(田间持水量的85％～100％)、I2(田间持水量的70％～85％)和I3(田间持水量的50％～65％)3个不同水分处理下的冠层温度,并同步获取试验地地面净辐射、...     

憎水性红曲黄色素的制备与表征

用乙酐处理水溶性红曲黄色素,得到了憎水性红曲黄色素,其最大吸收波长为490nm．由FTIR测定结果推测,在反应中可能产生酮与酸酐的缩合反应．反应后的红曲黄色素可以溶于多种较低极性的溶剂．在加热过程中,添加Al^3 的色素溶液稳定性较差,添加Sn^2 或Mg^2 的色素溶液比较稳定,而添加Fe^3 或Ca^2 后,色素溶液光密度则略有上升,色素溶液光密度随光照或水浴加热时间延长而呈接近线性下降．     

安太堡露天煤矿排土场景观结构及其分形研究

将平朔安太堡露天煤矿复垦区的5个排土场按照植被覆盖和地形划分为8个基本景观类型,包括耕地、草地、草灌混交、灌木混交、乔草混交、乔灌混交、新造复垦地和退化地,总计496个斑块。利用3S技术和分形理论对景观结构进行了分析,并讨论了景观特性及其变化的分形性质。结果表明：分维数的大小反映了景观斑块面积、斑块数量和平均斑块面积等因素的相互作用,反映了排土场内景观斑块的不规则程度和复杂程度;乔灌混交地和灌木混交地保持着较高的分维数,新造复垦地和草地的分维数较低,其它景观类型的分维数则差别不大;植被景观受多种因子的影响,在南排土场、西排土场受地表物质组成和地形的影响为主,其多样性指数较高,在内排土场、西排扩大区受植被类型的影响为主;草灌混交地的景观多样性远高于其它现有的复垦植被区,但其景观优势度则保持在较低水平上。南排、西排及西排扩大区的景观过程以控制水土流失、增加植被覆盖为主,内排则着重发展兼顾经济、生态和社会多种效益的生态农业和高效农业。     

Effect of dietary chitosan oligosaccharide complex with Ce (IV) on growth,immunity and disease resistance against Vibrio splendidus of sea cucumber,Apostichopus japonicas

An 8‐week feeding trial was conducted to investigate the effects of dietary chitosan oligosaccharide complex with cerium (Ce IV) (COS‐Ce) on growth performance, nonspecific immunity and disease resistance of sea cucumber, Apostichopus japonicas. Five isonitrogenous (18.6%) and isolipidic (1.1%) practical diets were formulated with graded level of COS‐Ce (0, 150, 300, 600 and 1200 mg kg^?1 dry feed), which were named as COS‐Ce/0, COS‐Ce/150, COS‐Ce/300, COS‐Ce/600, COS‐Ce/1200 respectively. Each diet was allocated to four replicates of sea cucumbers (Initial weight: 6.72 ± 0.02 g). Sea cucumbers were fed to apparent satiation once daily (19:00 hours) for 56 days. During the experiment, water temperature was kept at 16 ± 0.5°C, pH 7.8–8.2, dissolved oxygen beyond 5 mg L^?1, ammonia nitrogen below 0.5 mg L^?1 and salinity from 30‰ to 31‰. Results showed that the specific growth rate of sea cucumbers was significantly higher in COS‐Ce/600 than that in other four treatments. Activities of phagocytosis, respiratory burst, acid phosphatase and alkaline phosphatase in COS‐Ce/600 were significantly higher than that in COS‐Ce/0 (P < 0.05) respectively. On the contrary, cumulative mortality was the lowest in COS‐Ce/600 following 14 days exposure to Vibrio splendidus (P < 0.05). In conclusion, these results confirmed that dietary COS‐Ce had beneficial effects on growth performance, nonspecific immunity and disease resistance of sea cucumber.     

Occurrence and Effects of the Rhizocephalan Parasite,Polyascus gregarius,in the Chinese Mitten Crab,Eriocheir sinensis,Cultured in a Freshwater Pond,China

An epizootic outbreak of the parasitic barnacle, Polyascus gregarius, was reported for the first time in cultured commercial mitten crab, Eriocheir sinensis. Observations were made in a freshwater culture pond in Shenjia Dang, Zhejiang province, China, from June to October 2007. The surface morphology and appearance of the interna, externa, or scar of P. gregarius were recorded in 1464 crabs, including 871 males and 593 females. Overall prevalence of infection was 37.8 and 31.7% in male and female crabs, respectively. The monthly variation of infection was mainly dependent on the mortality of the host, with the highest prevalence (58.0% of males and 51.3% of females infected) in June, and the lowest (13.4% of males and 6.3% of females) in October. A host with multiple externae or scars was encountered frequently, with the maximum of 28 externae or 19 scars on a single crab. Being restricted in the culture pond, the hosts could not escape and return to the brackish water of the estuary; therefore, the externae were never exposed to male cyprids and remained unfertilized. As a result, all the externae degenerated and dropped off finally after 2–3 mo. This parasite caused castration, anecdysis, and increased mortality in the host, and therefore, had both direct and indirect effects on the commercial culture of E. sinensis. Infected males were castrated and displayed morphological modifications of secondary sexual characters. The size of infected crabs was significantly smaller than that of uninfected crabs because the molting was reduced by infection. After all the externae dropped off, the scarred host crabs finally died. A high mortality (possibly >50%) due to parasitism was observed in this study.     

几种添加剂对宽体舌鳎盐溶蛋白凝胶特性的影响

鱼肉盐溶蛋白的凝胶特性与鱼糜制品的质地密切相关,而盐溶蛋白的凝胶特性又受到许多因素影响。为研究添加转谷氨酰胺酶(TGase)、海藻酸钠、卡拉胶、魔芋胶对宽体舌鳎盐溶蛋白凝胶特性的影响,本实验通过四元二次通用旋转试验设计,采用响应面法建立了宽体舌鳎盐溶蛋白凝胶保水性(Y)和凝胶强度(y)与各添加剂用量的二次多项回归方程,确定了TGase、海藻酸钠、卡拉胶、魔芋胶的适宜添加量分别为0.36%,1.00%,1.00%,0.71%,添加后舌宽体鳎盐溶蛋白凝胶网状结构致密均匀,保水性和凝胶强度分别为60.36%和55.20 g,比对照组分别增加了36.41%和351.80%。结果说明,合适的添加剂组合可以显著的增加宽体舌鳎盐溶蛋白凝胶的保水性和凝胶强度。     

沙化土地信息提取研究

采用LandsatETM 多时相影像,在地类光谱特征分析的基础上,用分层分离的方法,提取出沙化土地信息。以全国沙漠化普查地类划分标准中的植被覆盖度为确定沙化土地程度的依据,通过建立NDVI和实测植被覆盖度的回归模型,确定不同程度沙化土地对应的植被覆盖度与NDVI的对应关系,用NDVI阈值进行划分,得到沙化土地程度图。     

黑龙江地区鲤疱疹病毒3型的流行病学调查及其主要囊膜蛋白的抗原表位预测

2015-2016年对来自黑龙江地区46个养殖场送检的鲤鱼进行锦鲤疱疹病毒(Koi herpes virus,KHV)的分离鉴定,并应用DNAStar等软件对检出的阳性样本的主要囊膜蛋白(Major envelop protein,MEP)基因进行生物信息学分析。结果显示,KHV的检出率约为6.5%,3株阳性样本具有相同的MEP基因序列,称之为KHV-HLJ1516。MEP基因开放阅读框为771 bp,编码256个氨基酸,相对分子质量为28 280.58,等电点为8.40。对KHV-HLJ1516的MEP基因序列同源性分析表明,其与KHV-GZ11分离株仅有1个碱基不同,但并未导致氨基酸发生改变,碱基相似性为99%;而与HZ419分离株相比,KHV-HLJ1516的MEP基因有3个碱基发生突变,相应的氨基酸由Asn变为IIe。聚类分析结果显示,KHV-HLJ1516与KHV-GZ11处于同一分支,而HZ419位于另一分支。B细胞抗原表位预测结果显示,KHV-HLJ1516的MEP的抗原表位主要位于4~11,24~40,42~63,82~110,209~218,238~249氨基酸区段。