狭果秤锤树自然种群分布格局

  目的  揭示狭果秤锤树Sinojackia rehderiana自然种群不同生活史个体分布格局，为该种群的保护提供科学依据。  方法  以自然分布于江西省永修县的狭果秤锤树种群为对象，采用相邻格子样方调查法、空间代替时间和O-ring完全随机零模型法，对狭果秤锤树自然种群不同生活史阶段个体的空间分布格局和空间关联性进行分析，探讨其空间分布格局形成原因。  结果  狭果秤锤树径级结构和高度级结构完整，幼苗和幼树的数量在整个种群中占绝对优势，种群更新状态良好，属增长型种群。狭果秤锤树种群在从幼苗发育到成树的过程中，在小尺度上聚集分布，大尺度上为随机分布至均匀分布；随着龄级的增加，聚集分布趋势减弱。在较小的尺度上，不同生活史阶段个体表现出正相关或不相关，在较大的尺度上则表现为不相关或负相关；负相关性主要表现在幼苗与中树、幼树与中树、幼树与成树间（P < 0.05）。  结论  在自然状态下，狭果秤锤树分布格局受自身生物学特性和种内、种间竞争影响，幼苗和幼树生长受限但数量较多，种群目前尚未达到稳定状态。     

Effects of irrigation and planting geometry on cotton(Gossypium hirsutum L.)fiber quality and seed composition

Background:Cotton fiber quality and seed composition play vital roles in the economics of cotton production systems and the cottonseed meal industry.This research aimed to examine the effects of different irrigation levels and planting geometries on fiber quality and seed composition of cotton(Gossypium hirsutum L.).We conducted a 2-year study in 2018 and 2019 in a warm,humid area in the Southeast United States on Dundee silt loam soil.There were three irrigation treatments in the study.The treatments included irrigating every furrow,or full irrigation(FI),every alternate furrow,or half irrigation(HI),and no irrigation,or rain-fed(RF).Planting geometries were on ridges spaced 102 cm apart and either a single-row(SR)or twin-rows(TR).Results:The results of high-volume instrument(HVI),advanced fiber information systems(AFIS)and near-infrared reflectance spectroscopy(NIRS)showed that irrigation and planting treatments played a significant role in fiber quality and seed composition.Across irrigation treatments,significant differences were seen in fiber properties,including fineness,maturity ratio,micronaire,neps,short fiber,strength,uniformity,upper half mean length(UHML),upper quartile length by weight(UQLw),and yellowness(+b).Irrigation and planting geometry(PG)had a significant effect on micronaire,strength,and UHML while their interaction was significant only for micronaire.The micronaire was negatively affected by irrigation as FI-SR,FI-TR,HI-SR,and HI-TR recorded 11%~12%lower over the RF-SR and TR treatments.The PG played a minor role in determining fiber quality traits like micronaire and nep count.Irrigation treatments produced significantly lower(3%~4%)protein content than rain-fed,while oil content increased significantly(6%~10%).Conclusions:The study results indicate a potential for improving cotton fiber and seed qualities by managing irrigation and planting geometries in cotton production systems in the Mississippi(MS)Delta region.The HI-TR system appears promising for lint and seed quality.     

黏虫CYP9A113基因的克隆及外源物质对基因表达的诱导效应

黏虫是我国作物上最重要的害虫之一。细胞色素P450能够参与昆虫外源物质代谢。本研究采用RACE技术克隆了一条编码黏虫P450基因的cDNA序列,并通过Real-time PCR技术,检测了4种外源物质对该基因表达的诱导效应。该基因被国际P450命名委员会命名为CYP9A113,GenBank登录号为KY436739。利用2.5%高效氯氟氰菊酯乳油的LD_(50)处理黏虫3 h,LD_(10)、LD_(30)和LD_(50)处理12 h和24 h,可诱导表达CYP9A113基因;20%氯虫苯甲酰胺悬浮剂的LD_(10)处理黏虫12、24和48 h,LD_(30)和LD_(50)处理24 h,CYP9A113基因表达呈诱导效应;0.1和0.5 mg/mL香豆素处理6、12、24和48 h,CYP9A113基因表达均呈诱导效应;0.1和0.5 mg/mL吲哚-3-甲醇处理3、6、12、24和48 h,CYP9A113基因表达均呈诱导效应。     

褐壳蛋鸡的蛋壳颜色(综述)(续1)

上期回顾:上一期介绍了褐壳蛋鸡所产鸡蛋的蛋壳中色素主要成分是原卟啉Ⅸ,但也存在微量的胆绿素及其锌螯合物,并介绍了计算蛋壳颜色的方法。     

Does intra-ruminal nitrogen recycling waste valuable resources? A review of major players and their manipulation

Nitrogenous emissions from ruminant livestock production are of increasing public concern and, together with methane, contribute to environmental pollution. The main cause of nitrogen-(N)-containing emissions is the inadequate provision of N to ruminants, leading to an excess of ammonia in the rumen, which is subsequently excreted. Depending on the size and molecular structure, various bacterial, protozoal and fungal species are involved in the ruminal breakdown of nitrogenous compounds(NC). Decelerating ruminal NC degradation by controlling the abundance and activity of proteolytic and deaminating microorganisms, but without reducing cellulolytic processes, is a promising strategy to decrease N emissions along with increasing N utilization by ruminants. Different dietary options, including among others the treatment of feedstuffs with heat or the application of diverse feed additives, as well as vaccination against rumen microorganisms or their enzymes have been evaluated. Thereby, reduced productions of microbial metabolites, e.g. ammonia, and increased microbial N flows give evidence for an improved N retention. However, linkage between these findings and alterations in the rumen microbiota composition, particularly NC-degrading microbes, remains sparse and contradictory findings confound the exact evaluation of these manipulating strategies, thus emphasizing the need for comprehensive research. The demand for increased sustainability in ruminant livestock production requests to apply attention to microbial N utilization efficiency and this will require a better understanding of underlying metabolic processes as well as composition and interactions of ruminal NC-degrading microorganisms.     

3种集虫装置对斜纹夜蛾诱捕器效果的影响

为了探索斜纹夜蛾性诱捕器的最佳使用效果,对诱捕器的3种集虫装置(瓶型、网袋型、塑料袋型)进行比较试验。结果表明,北京地区瓶型集虫装置效果最好,每个日均诱捕量为31.4头;泉州地区塑料袋型装置效果最好,日均诱捕量为54.7头。虫情动态分析可知,北京和泉州两地斜纹夜蛾的发生为害高峰期分别为9月上中旬和10月上中旬。     

Towards the sustainable intensification of agriculture—a systems approach to policy formulation

The sustainable intensification of agriculture involves providing sufficient food and other ecosystem services without going beyond the limits of the earth’s system. Here a project management approach is suggested to help guide agricultural policy to deliver these objectives. The first step is to agree measurable outcomes, integrating formal policy goals with the often much less formal and much more diverse goals of individual farmers. The second step is to assess current performance. Ideally, this will involve the use of farm-scale metrics that can feed into process models that address social and environmental domains as well as production issues that can be benchmarked and upscaled to landscape and country. Some policy goals can be delivered by supporting ad hoc interventions, while others require the redesign of the farming system. A pipeline of research, knowledge and capacity building is needed to ensure the continuous increase in farm performance. System models can help prioritise policy interventions. Formal optimization of land use is only appropriate if the policy goals are clear, and the constraints understood. In practice, the best approach may depend on the scale of action that is required, and on the amount of resource and infrastructure available to generate, implement and manage policy.     

山羊的饲养管理及疫病防控策略分析

在我国经济形势多样化发展的大背景下,当下社会建设对产业输出的需求也逐渐从传统的模式中脱离出来,不再以单一的物种为经济增长的根本,而是更加强调多元化建设。这种变化就要求相应的产业发展,也应当调整自身的节奏和步伐,顺应社会群众多样需求的整体趋势。而畜牧业作为保证社会日常供给的重要基础,在这种情况下也应当受到更加高度的重视和关注,特别是就山羊的饲养而言,要尤为强调其有序管理和疾病的防控。本文以山羊的饲养为出发点,重点对其饲养管理和疾病防治的策略进行分析。     

UCP1基因变异与绵羊生长及胴体性状的关联分析

试验旨在探讨解耦联蛋白1（UCP1）基因核苷酸变异对绵羊生长性状的性别差异和胴体性状的影响，以期能够筛选出可以提升绵羊生长及胴体性状的核苷酸变异，为提高绵羊相关重要经济性状的分子遗传标记提供材料。以9个绵羊品种为研究对象，用PCR-SSCP方法检测不同性别绵羊中UCP1基因内含子5区和外显子6区变异。利用Minitab 16.0软件中一般线性模型分析内含子5区等位基因与不同性别绵羊生长性状、公羔胴体性状的关联性。结果显示，绵羊UCP1基因内含子5区和外显子6区共检测到8个核苷酸变异，其中位点c.910 G/A突变导致p.Ala304Thr氨基酸变异。生长性状关联分析结果表明，内含子5区等位基因对绵羊生长性状的影响存在性别特异性，母羔中携带等位基因A₁的群体较缺失群体具有较低的初生重（P<0.05），公羔中携带等位基因C₁的群体较缺失群体具有较高的断尾重（P<0.05），未发现其他等位基因与羔羊的生长性状存在性别特异性。胴体性状关联分析结果表明，携带等位基因A₁的群体具有较低后腿瘦肉量、腰部瘦肉量和较高的肩部瘦肉比例（P<0.05），携带等位基因C₁的群体具有较低的后腿瘦肉比例（P<0.05），其他胴体性状均没有发现与等位基因存在显著相关，基因型分析结果与等位基因分析结果一致。结果提示，UCP1基因对绵羊的生长性状影响具有性别特异性，且携带等位基因A₁的公羔群体具有较低的胴体生产性状，为提高公羔胴体生产性能提供了理论依据。     

以遗传潜力推算最佳生长及经济效益的生猪饲料配方及自动化饲喂计划

饲养策略是针对整个猪群,这必然会导致自然资源的低效利用,甚至可能会扩大猪在屠宰时的个体差异。通过管理猪群均匀度做到精准饲喂有助于提高动物生产系统的效率。这个解决办法依赖于对营养供给与动物生产性能之间的精准预测、生产性能的持续监测和调节营养供给的饲喂系统。