Effect of light irradiation on dynamics of vitamin A compounds in rotifers and Artemia

ABSTRACT:   The dynamics of vitamin A (VA) compounds in live food during enrichment were examined under different light conditions. Rotifers Brachionus plicatilis and Artemia nauplii ( Artemia ) were enriched with or without 10 mg VA palmitate (VAp) in 1 L of culture medium for 24 h under either bright (2000 lx), or dark (<1 lx) conditions. VAp, retinol (ROH), retinal (RAL) and retinoic acid (RA) contents were analyzed at 0 h (before enrichment) and at 3, 6, 12, 18 and 24 h after the onset of enrichment. Retinoid content in rotifers enriched in darkness was always higher than that enriched under light. VAp content showed two peaks at 3 and 18 h in rotifers enriched in darkness, but it showed one peak at 3 h in rotifers enriched under light. ROH and RA contents increased over the 24-h period in rotifers enriched in darkness, whereas they decreased 12 h onward in rotifers enriched under light. In Artemia , VAp and ROH contents were always higher than when enriched under the bright condition, but their dynamics showed a similar pattern in Artemia enriched under dark and bright conditions.     

Abundance,distribution and diet of the common dolphin,Delphinus delphis,in the northern Aegean Sea (Greece)

1. The abundance, distribution and diet of the short-beaked common dolphin were investigated as part of the first detailed study on cetacean populations in the North Aegean Sea. Since 2004, the area has been proposed by national and international entities as a marine protected area for common dolphins and other cetacean species owing to its high biodiversity.
2. Abundance and distribution were investigated between 2005 and 2013 through dedicated scientific marine transect surveys, covering 14,701 km, in sea conditions of Beaufort sea state 3 and below. The line-transect sampling method was used to estimate relative abundance, using Distance 6.0 software. Encounter rate for this species in the study area was estimated to be 0.24 groups/100 km (1.5 dolphins/100 km), with a mean group size of 6.88 (SE = 1.90).
3. Common dolphin sightings were analysed for correlations with eight environmental variables (distance from the coast, depth, slope, median salinity, gradient of salinity, median temperature, gradient of temperature and mean current) using generalized additive modelling. Common dolphin sightings were significantly correlated to depth, temperature and salinity.
4. Stomach-content analyses were performed on eight suitable samples from common dolphins stranded in the study area. The trophic level of the species was calculated, indicating that this species is a top predator.
5. This research provides the first estimates for abundance and distribution and the first diet analysis for this Mediterranean Endangered dolphin species in the study area based on a year-round long-term study.

     

Application of soya phosphatidylcholine in tuna orbital oil enrichment emulsions for Artemia

Oil-seawater emulsions of 12%, 8%, 4% and 2% soya phosphatidylcholine (PC) in tuna orbital oil (TOO) (w:w) were tested with respect to their suitability as Artemia enrichment media. Levels of essential fatty acids (EFA) accumulated by feeding Artemia nauplii were measured after enrichment periods of 0, 14, 18 and 20 h, and the stability of polyunsaturated fatty acids levels in the emulsions were also monitored throughout the enrichment process. Artemia enrichment efficiency in terms of %DHA (docosahexaenoic acid, 22:6w-3) and DHA:EPA (eicosapentaenoic acid, 20:5w-3) ratios were similar for all four types of emulsions (10-12% and 1.7-1.8, respectively). However, 8% and 12% soya PC/TOO emulsions yielded nauplii with slightly higher mean lipid contents than the other two treatments (235-243 and 217-229 mg lipid g-1 dry body weight, respectively). Stability of polyunsaturated fatty acids (PUFA) levels within the emulsions in seawater, and of DHA and EPA levels in particular, correlated with soya PC concentration. In 12% soya PC/TOO emulsions, PUFA levels remained high after 20 h enrichment whilst those in the 2% and 4% soya PC emulsions showed a marked reduction by 18 h enrichment time. It is suggested that soya PC may protect PUFA levels in the emulsions in a dose-dependent manner, probably by acting as an antioxidant. No significant improvement in Artemia total lipid content or DHA:EPA ratio occurred when enrichment was continued for longer than 18 h. When using this enrichment system, it is preferable, therefore, to employ the 12% soya PC/TOO emulsion and to terminate the enrichment process at 18 h, thus preventing the risk of PUFA levels deteriorating in the emulsion.     

锯缘青蟹幼体饵料的营养强化

用酵母、水球藻、鱼油强化和豆油强化四种不同方式培养轮虫，再分别投喂锯缘青蟹幼体，分析测定轮虫和体的生化组成，结果显示，（1）不同方式培养的轮虫之间以及摄食这些轮虫的锯缘青蟹幼体之间的蛋白质含量都没有显著差异；（2）轮虫的脂类含量和脂肪酸组成与培养方式密切相关，小球藻轮虫的脂类含量最高，20：5n-3(EPA)占总脂肪酸的比例也最高 ，为18.05%，鱼油轮虫则含有最多的22：6n-3(DHA)，占总脂肪酸3.16%，脂类含量仅次于小球藻轮虫；（3）锯缘青蟹幼体的脂类含量和脂肪酸组成受相应饵料营养成分的影响。另外，幼体培育实验也发现，饵料营养成分影响幼体的存活率，结果表明，提高轮虫的EPA和DHA含量，尤其晨DHA含量，将有利于锯缘青蟹幼体的存活和发育。     

养分与CO2交互作用对番茄幼苗生长及一些生理指标的影响

营养液栽培条件下,研究了不同CO2浓度及养分供应强度对番茄幼苗生长及一些生理指标的影响。 发现CO2施肥增加了株高、茎粗、整株的鲜干重,壮苗指数、叶片数、花蕾数、光合作用速率,胞间CO2浓度。 CO2施肥降低了蒸腾速率,气孔导度,这些指标对CO2的响应随营养液浓度的改变而改变。CO2施肥增加了高 养分供应条件下的根冠比,降低了低养分供应强度下的根冠比,反映了番茄在高浓度CO2条件下对养分浓度 改变的适应特征。CO2施肥不仅提高了番茄幼苗对养分的利用能力,而且也减轻了由于养分浓度过高而带来 的负面影响。     

密云水库上游铁矿区重金属在胡敏酸中的分布特征研究

以北京市密云水库上游铁矿区为研究对象,研究了不同深度(0~20 cm和20~40 cm)土壤样品和胡敏酸中重金属的分布特征以及重金属与胡敏酸之间的相关性。根据国际腐殖质协会提供的胡敏酸提取方法从土壤样品中提取胡敏酸,使用ICP-MS测定了土壤样品和胡敏酸中重金属V、Cr、Co、Ni、Cu、Zn、Cd和Pb的含量,并使用相关性分析法和富集因子法研究了重金属和胡敏酸之间的相互关系。结果表明:土壤样品中V、Cr、Co、Ni、Cu、Zn、Cd和Pb在0~20 cm的平均含量高于20~40 cm;胡敏酸中V、Co、Ni、Cu、Zn和Pb在0~20 cm的平均含量高于20~40 cm,Cr和Cd则相反。相关性分析表明V、Cr、Co、Ni、Cu、Cd和Pb的含量与有机质含量和胡敏酸含量均表现出显著相关性,V、Co、Cu、Cr、Ni和Zn的含量与胡敏酸和有机质含量之比(HA/OM)呈负相关。富集因子分析表明胡敏酸对V、Cr、Ni、Zn和Pb的结合能力不强,而对Cu元素的结合能力很强;0~20 cm的胡敏酸对V、Cr、Co、Ni、Cu、Zn和Pb的富集程度高于20~40 cm,Cd则在20~40 cm的胡敏酸中富集程度更高。     

The influence of seagrass donor source on small‐scale transplant resilience

1. Concern for conservation of seagrass habitat has prompted international transplantation‐style restoration efforts. A recent review of these restoration efforts has highlighted the low success associated with small‐scale restorations, yet scaling up transplantation effort may be too costly for underfunded regions. Small‐scale transplant survival can be enhanced with alleviation of two underlying issues: restoration site selection and donor site selection.
2. To investigate appropriate donor source selection, donor site environmental influence on seagrass (Halodule wrightii) transplant survival was examined by transplanting donor cores from two environmentally disparate sites to a transplantation site with limited environmental uncertainties. Donor sites were chosen to represent either end of a benthic light gradient (high versus low) to elucidate seagrass resilience to transplantation stress, with respect to donor site conditions.
3. After total loss of the first trial, a second trial was conducted with stabilizing mesh placed over transplants to reduce stingray bioturbation. The second trial resulted in 100% survival of high light transplants after 12 months and moderate survival (30–60%) of low light transplants for the first six months.
4. At 18 months, the second trial ended after sediment burial from a hurricane. One year post‐burial, a patch of H. wrightii recovered at the high light transplant site; after six years the patch expanded to approximately 74 m², an area 37‐fold larger than originally planted.
5. Results from this transplant experiment provide evidence that donor environment plays a role in transplant resilience. The transplants sourced from high light had 47% greater leaf area per shoot, were more resistant to transplantation stress, and recovered following an extreme event relative to low light transplants. Therefore, selection of donor plants with more resilience features, a transplantation site with limited environmental uncertainties, and adaptive intervention can enhance seagrass resilience at a small planting scale.

     

CO2增施与养分交互作用对日光温室番茄生长的影响

以“中杂105”番茄为试验材料,在日光温室基质栽培条件下研究了CO2增施浓度和养分水平对番茄生长的影响。试验设置4个CO2水平,分别为不增施（C0）、(700±50)μmol/mol（C1）、(1000±50)μmol/mol（C2）、(1300±50)μmol/mol（C3）;以山崎番茄配方营养液浓度1个剂量（S）为基准设3个养分水平,分别为1/2S（F1）、1S（F2）、2S（F3）。结果表明：在相同CO2处理条件下,提高养分有利于番茄茎粗、叶片SPAD值、植株干、鲜质量和第一穗果质量的增加,并使开花日期提前;在相同养分处理条件下,增施CO2可以显著增加番茄的茎粗、叶片SPAD值、植株干、鲜质量和第一穗果质量,显著降低第一花序节位,并使开花日期提前;增施（1000±50）μmol/mol和（1300±50）μmol/mol的CO2可以显著提高叶片中氮含量。中低养分条件下,增施（1000±50）μmol/mol CO2即可使番茄第一花序节位降低1.0个节位、开花日期提早5~8d,还使第一穗果质量显著高于对照。高养分条件下,增施（1300±50）μmol/mol CO2的处理番茄第一花序节位最低,比对照（C0F3）降低1.7个节位,开花日期最早,比对照提前10d,第一穗果质量最大,比对照高出24.15%。番茄的第一花序节位、开花日期和第一穗果质量对CO2响应的程度依赖于养分水平,高养分使这些指标对CO2响应的程度提高。综合各项生长指标,C3F3处理番茄茎粗最大、第一花序节位最低、开花最早,是最优水平组合。     

青海乐都富硒区6种主要蔬菜富硒能力研究

【目的】研究青海乐都富硒区主要蔬菜对于硒的生物富集能力。【方法】2010年,以研究区内6种主要蔬菜(大蒜、萝卜、胡萝卜、甜菜、菊芋、马铃薯)为研究对象,共采集135个植物样品和65个土壤样品,测定样品中的硒含量,并依据我国粮食中硒含量生态景观界限值对不同蔬菜的富硒水平进行评价。【结果】青海乐都富硒区6种主要蔬菜的硒含量为1.4~574.9μg/kg,大蒜、萝卜、胡萝卜、甜菜、菊芋、马铃薯6种蔬菜硒含量平均值依次为181.4,103.0,97.8,88.2,119.8和80.3μg/kg,其对土壤硒的富集能力依次表现为大蒜萝卜胡萝卜菊芋甜菜马铃薯。6种蔬菜中,有90.4%的大蒜样品达到富硒水平,明显高于其他蔬菜。【结论】不同蔬菜对硒的累积能力存在差异,其中大蒜对土壤硒的富集能力最强。     

许氏平鲉微卫星标记的开发及评价

采用磁珠富集法筛选具多态性的许氏平鲉微卫星标记,并用一个野生群体对其多态性进行了评价。三引物PCR法筛选出58个阳性克隆进行了测序,共得到47个含微卫星核心的DNA序列,筛选出15对具有多态性的微卫星引物。所有位点上共得到66个等位基因片段,每个位点的观测等位基因数(A)为2~14个,平均等位基因数为4.4,观测杂合度(Ho)、期望杂合度(He)范围分别为0.062 5~0.968 8、0.061 5~0.929 1。每个位点的多态信息含量(PIC)显示,有6个位点表现出高度或中度多态。经Bonferroni校正后,HJ2-32、HJ4-27、HJ4-45和HJ4-47四个位点的等位基因频率显著偏离了Hardy-Weinberg平衡。连锁不平衡检测表明,各位点间无连锁不平衡现象。