闽南—台湾浅滩渔场鲐鲹鱼类群聚资源生产量和允许总渔获量

以海洋生态系营养动力学为基础,采用Steele模式估算闽南—台湾浅滩渔场中上层鱼类资源年生产量为86.14×10~4t,进而以鲐鲹鱼类群聚资源在中上层鱼类资源的比例,估算鲐鲹鱼类群聚资源的年生产量为51.76×10~4t。Gulland和MSY简单模式估算鲐鲹鱼类群聚资源的最大持续产量分别为25.00×10~4t和25.88×10~4t。Schaefer和Fox剩余产量模式估算鲐鲹鱼类群聚资源的最大持续产量分别23.60×10~4t和23.41×10~4t,最大持续捕捞力量分别为1140.41×10~4kw·d和1266.66×10~4kw·d。折算为福建灯光围网渔船分别为424和471组,并从开发现状和种群生态学及捕捞死亡等参数分析鲐鲹鱼类群聚资源的开发前景。     

乌拉圭林业的经验与启示

近 10多年来乌拉圭林业迅速崛起,成为潜在的世界木材主要出口国。意识到国际市场上木材需求量不断增长、价格稳定,1987年调整林业发展方向,重点发展出口导向型商业人工林。借鉴新西兰和智利的经验,通过补贴造林、减免税收、软贷款等优惠政策和刺激措施,加上地势平坦、气候土壤条件优越、人力资源素质高、社会经济秩序稳定以及交通便利,吸引了众多国内外投资者对人工林的大量投资,投资的年内部收益率大约是14%～27%。但是,大量采用桉树和松树等外来树种营建速生丰产林,会面临地力衰退和生物多样性丧失的危险。     

圆草捆自动缠网装置设计与试验

设计了一种圆草捆自动缠网装置,该装置采用凸轮机构作为传动和控制机构,使用摆动连杆机构作为凸轮从动件,对引网作业机构、缠网计数机构和切网作业机构进行控制,实现了对圆草捆缠网、记录缠网圈数和切网的自动作业。性能试验结果表明:该装置可对宽度为80～120 cm的干草捆或宽度为80～100 cm的青贮圆草捆进行自动作业,装置对1.2 m宽干草捆缠网3圈、对1.0 m宽青贮玉米圆捆缠网4圈时,作业性价比最高。     

Modelling soil tillage and mulching effects on soil water dynamics in raised-bed vegetable rotations

Reduced tillage and mulching may bring about new production systems that combine better soil structure with greater water use efficiency for vegetable crops grown in raised bed systems. These are especially relevant under conditions of high rainfall variability, limited access to irrigation and high soil erosion risk. Here we evaluate a novel combination of empirical models on water interception and infiltration, with a soil-water balance model to evaluate water dynamics in raised bed systems on fine Uruguayan soils to analyze the effect of reduced tillage, cover crops and organic matter addition on soil physical properties and water balance. In the experiment mulching increased water capture by 9.5% and reduced runoff by 37%, on average, leading to less erosion risk and greater plant available water over four years of trial. Using these data we calibrated and evaluated different models that predicted interception + infiltration efficiently (EF = 0.93 to 0.95), with a root mean squared error (RMSE) from 0.32 to 0.40 mm, for an average observed interception + infiltration of 28.8 mm per day per rainfall event. Combining the best model with a soil water balance resulted in predictions of total soil water content to 1 m depth (SWC_T) with RMSE ranging from 4.5 to 10.3 mm for observed SWC_T ranging from 180.4 to 380.6 mm. Running the model for a four-year crop sequence under 10 years of Uruguayan historical weather revealed that reduced tillage required on average 141 mm yr⁻¹ less irrigation water than conventional tillage combined with organic matter application, thus enabling a potential increase in irrigated area of vegetable crops and crop yields. Results also showed the importance of inter-annual rainfall variability, which caused up to 3-fold differences in irrigation requirements. The model is easily adaptable to other soil and weather conditions.     

Assessing Relationships Between Genetic Evaluations Using Robust Regression with an Application to Holsteins in Uruguay

Globalization of dairy cattle breeding has created a need for international sire proofs. Some early methods for converting proofs from one population to another are based on simple linear regression. An alternative robust regression method based on the t-distribution is presented, and maximum likelihood and Bayesian techniques for analysis are described, including the situation in which some proofs are missing. Procedures were used to investigate the relationship between Holstein sire proofs obtained by two Uruguayan genetic evaluation programs. The results suggest that conversion equations developed from data including only sires having proofs in both populations can lead to distorted results, relative to estimates obtained using techniques for incomplete data. There was evidence of non-normality of regression residuals, which constitutes an additional source of bias. A robust estimator may not solve all problems, but can provide simple conversion equations that are less sensitive to outlying proofs and to departures from assumptions.     

显性核不育油菜圆叶纯合两型系Gd1AB的选育

采用杂交、兄妹交和自交等育种手段,育成园叶显性纯合两型系Gd1AB。利用该两型系与花叶临保系进行全不育系制种,圆叶可作为苗期育性的指示性状,能有效地区别纯合两型系内可育株迟拔或漏拔而产生的杂株,从而提高全不育系的纯度。     

Transgenic mouse offspring generated by ROSI

The production of transgenic animals is an important tool for experimental and applied biology. Over the years, many approaches for the production of transgenic animals have been tried, including pronuclear microinjection, sperm-mediated gene transfer, transfection of male germ cells, somatic cell nuclear transfer and the use of lentiviral vectors. In the present study, we developed a new transgene delivery approach, and we report for the first time the production of transgenic animals by co-injection of DNA and round spermatid nuclei into non-fertilized mouse oocytes (ROSI). The transgene used was a construct containing the human CMV immediate early promoter and the enhanced GFP gene. With this procedure, 12% of the live offspring we obtained carried the transgene. This efficiency of transgenic production by ROSI was similar to the efficiency by pronuclear injection or intracytoplasmic injection of male gamete nuclei (ICSI). However, ICSI required fewer embryos to produce the same number of transgenic animals. The expression of Egfp mRNA and fluorescence of EGFP were found in the majority of the organs examined in 4 transgenic lines generated by ROSI. Tissue morphology and transgene expression were not distinguishable between transgenic animals produced by ROSI or pronuclear injection. Furthermore, our results are of particular interest because they indicate that the transgene incorporation mediated by intracytoplasmic injection of male gamete nuclei is not an exclusive property of mature sperm cell nuclei with compact chromatin but it can be accomplished with immature sperm cell nuclei with decondensed chromatin as well. The present study also provides alternative procedures for transgene delivery into embryos or reconstituted oocytes.     

Two new records of helminth parasites of domestic cat from Uruguay: Alaria alata (Goeze, 1782) (Digenea, Diplostomidae) and Lagochilascaris major Leiper, 1910 (Nematoda, Ascarididae)

Eight helminth taxa were recovered from the necropsy of four stray domestic cats from Colonia Miguelete, county of Colonia, Uruguay. Two of them are recorded for the first time for domestic cats in that country: Alaria alata (Goeze, 1782) from the small intestine (which is also the first trematode species found in domestic cat in Uruguay), and Lagochilascaris major Leiper, 1910 from the pharynx. The remaining helminth species found were Toxocara mystax (Zeder, 1800) and Spirometra sp. from the small intestine, Trichuris serrata (von Linstow, 1879) from the caecum, Eucoleus aerophilus (Creplin, 1839) from the trachea, and Pearsonema feliscati (Diesing, 1851) from the urinary bladder. Moreover, four female specimens of an unidentified Spiruroidea were collected from the stomach and small intestine of one host.     

Characterization of Equine Phospholipase C Zeta: A Review and Preliminary Results on Expression Defects in Subfertile Stallions

In all mammalian species studied thus far, fertilization results in a series of intracellular Ca²⁺ ([Ca²⁺]_i) increases, referred to as oscillations, responsible for driving oocyte activation and embryonic development. Current evidence supports the notion that sperm-borne phospholipase C zeta (PLCZ) is responsible for the initiation of these [Ca²⁺]_i oscillations. Although this appears to be a highly conserved mechanism for oocyte activation, differences in PLCZ sequence, activity, and expression do exist among different species. Herein, we summarize the information supporting PLCZ as the oocyte-activating factor in mammals and present our current knowledge regarding the characterization of this protein in the horse. The equine sequence yielded a protein of high relative [Ca²⁺]_i-releasing activity. Equine PLCZ was expressed over the head region overlying the acrosome, equatorial segment, connecting piece between the head and midpiece, and on the principal piece of the flagellum of stallion sperm. Equine PLCZ expressed both over the head and tail sperm regions was catalytically active, with the latter representing a characteristic unique to the horse. We also present preliminary data in subfertile stallions displaying PLCZ expression defects, although further research is required to establish a clear association between these defects and fertility problems in the horse. In summary, the information presented raises the questions of whether equine PLCZ could play diverse roles in sperm physiology and/or become a marker for the evaluation of stallion fertility, both of which are worthy of further investigation.     

优质圆粒加工专用型裸燕麦新品种“坝莜19号”选育

“坝莜19号”是张家口市农业科学院采取野生燕麦与裸燕麦远缘杂交、裸燕麦品种间复合杂交和系谱法选育而成。2021年4月通过河北省科学技术厅成果登记,登记号：20210501,是我国第一个籽粒为卵圆形的裸燕麦品种,综合性状优异,免疫燕麦坚黑穗病,高产稳产,适应性广,在同类研究中居国际先进水平。