鲜活黄鳝剖切装置设计与试验

针对目前鳝鳅类淡水鱼类人工剖切劳动强度大、工作效率低、安全性差等问题,该研究以黄鳝（Monopterus albus）为试验对象,基于黄鳝生活习性及鱼体特征,在黄鳝鱼体夹持受力特性分析的基础上,开展了黄鳝鱼体头尾及腹背定向和鱼体夹送剖切方法研究,设计并研制了鲜活黄鳝剖切装置。剖切装置由倾斜料斗、进鱼通道、夹持对辊、剖切刀盘等组成,其中进鱼通道长180 mm,入口处直径28 mm;夹持辊边缘为上宽下窄的锯齿状结构;剖切刀盘直径114 mm。以夹持辊直径、夹持辊初始间隙、夹持辊转速、刀盘露出高度为影响因素,以剖切可接受性评分为评价指标开展相关试验,通过单因素试验探究了各因素对黄鳝剖切效果的影响。试验结果显示,当夹持辊直径为180 mm时夹送效果较好;夹持辊初始间隙为8 mm时鱼体腹部剖面感官评分最高;夹持辊直径一定时,高转速下的夹送效果明显优于低转速;随着刀盘露出支撑面高度的增加,黄鳝腹部剖切效果的感官评分逐渐增加。正交试验结果表明：夹持辊转速为180 r/min、刀盘露出支撑面高度为22 mm、夹持辊初始间隙为8 mm时,黄鳝腹部剖切效果的感官评分最高;通用性试验结果表明：该装置能够较好地适用于不同规格大小的黄鳝,满足实际加工要求,生产量可以达到24.3条/min。研究结果可为鳝鳅类淡水鱼剖切装置的研发提供参考。     

‘富有’甜柿砧木种质早期亲和性研究

以25个柿砧木为材料,对‘富有’甜柿进行嫁接亲和力比较试验,通过连续多年观测多项生理生化指标,并辅以数学多元统计的方法,分析比较不同砧木嫁接‘富有’甜柿后生长差异情况,评价不同砧木嫁接‘富有’甜柿的亲和性,初步筛选并获得具有推广潜力的‘富有’系亲和性砧木。结果表明,柿不同近缘种嫁接‘富有’甜柿的嫁接成活率、嫁接保存率、嫁接口愈合情况差异显著,本砧嫁接‘富有’甜柿嫁接亲和性相对稳定,不因本砧品种而异。综合评价结果表明,君迁子824和君迁子848与‘富有’的早期亲和性较好。     

昆明市景观格局变化及其生态环境效应研究

以昆明城市景观为研究对象,采用景观格局指数、景观生态风险指数和生态系统服务价值系数探究1990—2018年景观格局变化及其生态环境效应,利用GWR模型分析生态环境效应与建设用地扩展的相关性。结果表明：市域景观类型变化程度在1990—2000年的城市化起步阶段相对稳定,在2000年后的城市化加速阶段动态变化加剧;景观格局指数变化呈稳定—不稳定趋势,1990—2000年,景观破碎度、形状不规则程度轻微下降,2000年后景观边界复杂程度加剧,优势景观的控制作用在减小,景观总体趋于破碎和均匀。景观格局变化带来了生态过程的变化,市域景观生态风险和生态系统服务价值均在降低;景观生态风险、生态系统服务价值在城市化水平最高的滇池流域内呈现出低等级区的环湖之势,其扩展路径与城市发展路径基本一致。生态环境效应总体均呈现出与建设用地扩展的负相关,且2010—2018年的负相关达到峰值,说明城市化加快带来了景观生态风险和生态系统服务价值的降低;建成区边缘的景观生态风险与建设用地扩展呈正相关,是景观生态风险的重点防控区。     

棉铃虫V-ATP酶E亚基基因克隆及表达分析

为进一步探明V-ATP酶亚基的功能,克隆了棉铃虫V-ATP酶E亚基开放阅读框;并通过荧光定量PCR,测定了V-ATP酶E亚基在棉铃虫不同发育阶段和不同组织中的基因表达量。结果表明,棉铃虫V-ATP酶E亚基开放阅读框长681 bp,编码226个氨基酸;V-ATP酶E亚基是一个保守亚基,与斜纹夜蛾的氨基酸序列一致性高达92%;V-ATP酶E亚基在棉铃虫卵、幼虫、蛹和成虫等发育阶段都有表达,以5龄幼虫表达量为最高,在触角、头、胸、腹、足、翅、外生殖器和中肠等组织中亦均有表达,其中在4龄中肠中表达量最高。说明V-ATP酶E亚基在棉铃虫的生长发育及代谢过程中发挥着重要作用。     

Drought effects on water use efficiency, freezing tolerance and survival of Eucalyptus globulus and Eucalyptus globulus × nitens cuttings

Genetic improvement of Eucalyptus genotypes for drought and frost resistance is essential for successful intensive management of commercial plantations. Understanding the physiological mechanisms that relate water use and frost resistance for highly deployed genotypes may allow for better prediction of their future performance, genetic selection and seedling management for site specific purposes. We studied whether instantaneous water use efficiency (WUE _i ) may serve as drought, freezing and photoinhibition tolerance predictor by studying its response on six E. globulus clones (Eg1–Eg6) and four E. globulus × E. nitens hybrid seedlings (Egn1–Egn4) under drought and irrigated (control) treatments. Net photosynthesis (A) and transpiration (E) were studied using a gas exchange system in order to calculate WUE _i (A/E). Simultaneous chlorophyll a fluorescence measurements were performed to assess the non photochemical quenching components. Frost tolerance of plants under control and drought treatments were evaluated by measuring temperatures that exert 50% photoinactivation of photosystem II. Finally, drought tolerance was evaluated by plant survival within each genotype after rehydration. Our results showed significant genotype variability in the rate of soil and xylem water potential decrease during drought. While most of the genotypes reached ?4.0 MPa in about 35 days of drought, genotypes Eg6 and Egn4 required 56 days of drought to reach this xylem water potential. WUE _i exhibited significant differences among genotypes and irrigation treatments. Genotypes Eg5 and Egn4 increased their WUE _i between 70 and 80% after drought. This was associated with a more conservative control of water loss at the stomatal level combined with maintenance of relatively higher rates of net photosynthesis than the other genotypes under drought conditions. Plants exposed to drought were more freezing tolerant than control plants, having in average 3°C lower LT₅₀ than well irrigated ones. There was no a clear correlation between WUE _i and drought tolerance or drought-induced photoinhibition, however WUE _i was inversely correlated with LT₅₀. Our results suggest that WUE _i is not suitable by itself to select drought tolerant genotypes, but may provide evidence for discarding drought sensitive genotypes. In addition, it could provide valuable information to select for freezing tolerance.     

A set of novel RNAs transcribed from the chloroplast genome accumulates in date palm leaflets affected by brittle leaf disease

Brittle leaf disease or maladie des feuilles cassantes (MFC) is a lethal disorder of date palms that has assumed epidemic proportions in the oases of southern Tunisia. After a prolonged period during which palms are declining, the disease ends with the death of the palms. Whereas no pathogen could ever be associated with the disease, leaflets of affected palms have been previously shown to be deficient in manganese. Analysis of RNA preparations from leaflets of MFC-affected palms revealed the presence of a set of novel RNAs (MFC-RNAs) of sense and antisense polarities, which are homologous to various regions of the date palm chloroplast genome, such as the regions containing genes rrn5S-trnR(ACG) and trnM(CAU)-atpE. In the RNA preparations obtained from leaflets of affected palms, some of these RNAs are present as double-stranded species (MFC-dsRNAs), as witnessed by results from cellulose chromatography, end labeling, RNase digestion, and northern hybridization with strand specific probes. These MFC-RNAs represent a novel type of host-derived RNAs, and their presence in MFC-affected date palms is of diagnostic value.     

Exploitation shifted trophic ecology and habitat preferences of Mediterranean and Black Sea bluefin tuna over centuries

During recent decades, the health of ocean ecosystems and fish populations has been threatened by overexploitation, pollution and anthropogenic-driven climate change. Due to a lack of long-term ecological data, we have a poor grasp of the true impact on the diet and habitat use of fishes. This information is vital if we are to recover depleted fish populations and predict their future dynamics. Here, we trace the long-term diet and habitat use of Atlantic bluefin tuna (BFT), Thunnus thynnus, a species that has had one of the longest and most intense exploitation histories, owing to its tremendous cultural and economic importance. Using carbon, nitrogen and sulphur stable isotope analyses of modern and ancient BFT including 98 archaeological and archival bones from 11 Mediterranean locations ca. 1st century to 1941 CE, we infer a shift to increased pelagic foraging around the 16th century in Mediterranean BFT. This likely reflects the early anthropogenic exploitation of inshore coastal ecosystems, as attested by historical literature sources. Further, we reveal that BFT which migrated to the Black Sea–and that disappeared during a period of intense exploitation and ecosystem changes in the 1980s–represented a unique component, isotopically distinct from BFT of NE Atlantic and Mediterranean locations. These data suggest that anthropogenic activities had the ability to alter the diet and habitat use of fishes in conditions prior to those of recent decades. Consequently, long-term data provide novel perspectives on when marine ecosystem modification began and the responses of marine populations, with which to guide conservation policy.     

蛋用鹌鹑IGF-1R基因的多态性与体尺性状相关性分析

类胰岛素生长因子1型受体(IGF-1R)基因是类胰岛素生长因子(IGFs)在生物体内发挥作用的主要效应器,对机体生长发育进程中有重要影响。为探讨IGF-1R基因多态性与蛋用鹌鹑体尺性状的相关性,采用PCR产物直接测序方法对中国黄羽鹌鹑、北京白羽鹌鹑、朝鲜鹌鹑3种蛋用鹌鹑的IGF-1R基因进行多态性分析,并对IGF-1R基因的多态性与鹌鹑体尺性状进行相关性分析。结果表明,在3个蛋用鹌鹑群体中检测到IGF-1R基因A57G和A72T两个突变位点,A57G位点发生了A/G碱基突变,有AA、AG和GG三种基因型;A72T位点发生了A/T碱基突变,有AA、AT和TT三种基因型。中国黄羽鹌鹑的A57G位点对胫长、胸骨长和胫围有显著影响(P<0.05),A72T位点对体质量和胸骨长有显著影响(P<0.05),组合基因型AGAA对体质量有显著影响(P<0.05),组合基因型AAAA对胫长、胸骨长、胫围有明显影响(P<0.05)。北京白羽鹌鹑的A57G位点对体质量、胫长、体长、胫围有显著影响(P<0.05),A72T位点对胸骨长有显著影响(P<0.05),组合基因型AAAA对体质量和胸骨长有显著影响(P<0.05),组合基因型AAAT、GGAA、GGAT对胫长有显著影响(P<0.05),组合基因型GGAA对胸深有显著影响(P<0.05)。朝鲜鹌鹑的A57G位点对体质量有显著影响(P<0.05),A72T位点对胸骨长和胫围有显著影响(P<0.05),组合基因型AGAA对体质量有显著影响(P<0.05),组合基因型AGAT对胫长和胸宽有显著影响(P<0.05)。因此,IGF-1R基因可以作为候选基因应用于蛋用鹌鹑体尺性状的分子标记辅助选择。