Grazing management for more resilient mixed livestock farming systems on native grasslands of southern South America

Droughts in southern South America affect grazing systems in many ways. They reduce biomass productivity; decrease livestock feed intake, weight and reproductive performance; increase farmers’ costs; and reduce farm income. It was hypothesized that simple grazing management variables affect the resilience of grazing systems to droughts at the paddock and farm scales. The effects of grazing management on herbage and animal production were assessed at paddock level, and how technological and structural variables relate to the production and economic performances at farm level. Results of a grazing experiment controlling herbage allowance at paddock level showed that resistance of herbage accumulation and animal live weight to drought was significantly higher for paddocks with higher pre‐drought herbage allowance than for those managed to low herbage allowance treatments. A strong positive linear relationship was found between pre‐drought herbage height and resistance of herbage accumulation rate (p < .01). In a longitudinal study of nine farms in Uruguay, resistance of cow pregnancy rate to drought was positively correlated with cow pregnancy rate (r = .72, p = .02) and farm net income (r = .78, p = .02), and negatively correlated with sheep‐to‐cattle ratio (r = ?.80, p = .01). These correlations suggest that farms with higher incomes and low proportions of sheep in the herd withstand drought better (in terms of pregnancy rate). Four common regional production strategies were identified that react differently when farmers face drought, and these results can aid farmers in those regions to design more resilient mixed livestock farming systems and can inform policymakers about effective strategies for mitigating drought impacts in the region.     

SA、MeJA、ACC和苹果轮纹病病原菌诱导湖北海棠MhWRKY1基因的表达

 【目的】从湖北海棠叶片中克隆MhWRKY1转录因子的全长cDNA序列,分析该基因在各种组织中(叶、茎、根)的表达特性,并分析SA、MeJA、ACC在叶、茎、根中诱导MhWRKY1基因的表达模式以及苹果轮纹病病原菌诱导条件下湖北海棠叶片中该基因的表达特性。【方法】利用电子克隆技术和RT-PCR验证相结合的方法,从SA诱导的湖北海棠全长cDNA文库中,克隆MhWRKY1转录因子的全长序列;利用生物信息学的方法对其进行结构和功能的初步分析;利用实时荧光定量RT-PCR技术分析该基因在不同组织中的表达以及在SA、MeJA、ACC和苹果轮纹病病原菌诱导下的表达特性。【结果】克隆了MhWRKY1基因的全长cDNA序列为1 338 bp,GenBank数据库登录号为FJ598139。生物信息学分析表明,该基因最大开放阅读框为993 bp,编码330个氨基酸。推导的氨基酸序列与杨树WRKY26、杨树WRKY20、大豆WRKY,马铃薯WRKY2、烟草WRKY、拟南芥WRKY7、水稻WRKY53的同源性分别为68%、68%、66%、60%,59%,49%和43%。该转录因子含有1个WRKY结构域,其N端含有1个WRKYGQK结构域,C端含有1个C2H2锌脂结构,属于第Ⅱ类型的转录因子。表达分析结果表明,MhWRKY1在叶和茎中的表达量较大,分别是根的4.81和3.75倍。在湖北海棠叶、茎、根中,SA、MeJA、ACC都可以诱导该基因的表达。另外,在所研究的72 h内,苹果轮纹病病原菌可以诱导该基因表达,且表达量在12 h达到最大,是未处理之前的9倍左右。【结论】MhWRKY1转录因子可能参与SA、MeJA和ET介导的植物抗病防卫反应的基本信号通路,并且参与对苹果轮纹病病原菌引起的防卫反应,在湖北海棠的的抗病过程中可能起着非常重要的作用。     

法国现代园林艺术风格简析

对20世纪后期法国园林的杰出代表巴黎雪铁龙公园、拉.维莱特公园以及贝尔西公园进行介绍,从点、线、面层次上分析其设计要素,在此基础上简析了其艺术与文化风格,以了解法国现代园林设计的不同特点,并总结法国现代园林中优秀的设计方法。     

番茄晚疫病菌研究进展

本文从番茄晚疫病菌的交配型、生理小种、线粒体DNA单倍型、同工酶基因型、DNA指纹图谱等方面的研究进行了综述,并对目前生产和研究中存在的问题和今后的研究方向进行了概述.     

鸭梨几丁质PbChiIV的克隆与表达

【目的】从鸭梨果实中克隆PbChiIV的全长cDNA序列,检测PbChiIV在根、茎、叶、果实以及在水杨酸（SA）和梨轮纹病菌诱导下的表达特性,以探讨该基因与SA信号转导及抗梨轮纹病菌的相关性。【方法】设计特异引物,克隆PbChiIV的全长序列,将测序得到的核苷酸序列和推导的氨基酸序列在NCBI上用BLAST进行序列相似性分析,利用BiotEdit软件对氨基酸序列进行比对,利用MEGA6.0构建系统发育树,利用实时荧光定量PCR技术分析该基因在梨不同组织以及在SA和梨轮纹病菌诱导下的表达。【结果】克隆了PbChiIV的cDNA序列为819 bp,GenBank数据库登录号为KJ872676。生物信息学分析表明,PbChiIV编码272个氨基酸,与沙梨的同源性达100%,与毛果杨（XP_006376418.1）、葡萄（NP001268173.1）、拟南芥（CAA74930.1）、紫花苜蓿（ACL36992.1）、蒺藜苜蓿（AAR87869.1）、豇豆（CAA61281.1）、榛子（AEM97876.1）、东方山羊豆（AAP03085.1）、葡萄（NP_001268075.1）、华东葡萄（ABY66958.1）、葡萄（AAB65777.1）、烟草（BAF44533.1）和海岛棉（AER29902.1）的同源性分别为79%、73%、73%、72%、72% 、72%、69%、68%、67%、67%、65%、67%和62%,属于第IV类几丁质酶基因。表达分析表明,PbChiIV在根中的表达量最大,分别是茎和叶的4.32和2.96倍,其次是在果实中的表达量,分别是茎和叶的2.48和1.70倍,在叶片和茎中的表达相对较低。在鸭梨幼果和成熟期果实中,SA和梨轮纹病菌均可诱导该基因表达。SA处理后基因的最大表达量是对照的2.83和3.8倍,病原菌处理后基因的最大表达量是对照的1.82和1.66倍,SA、病原菌处理后基因的最大表达量是对照的2.49和3.43倍,表达量分别在72、24和72 h达到最大值。【结论】PbChiIV可能参与SA介导的植物抗病防卫反应的信号通路,推测其参与梨轮纹病菌引起的防卫反应,在鸭梨抗病过程中起作用。     

The sea cucumber fishery in Australia's Great Barrier Reef Marine Park follows global patterns of serial exploitation

Tropical sea cucumber fisheries follow a predictable pattern of serial depletion. Overfishing is exacerbated in developing countries where management systems lack capacity to control large numbers of fishers influenced by poverty. In contrast, the tropical sea cucumber fishery in Australia's World Heritage listed Great Barrier Reef Marine Park (GBRMP) is operating in a developed high‐income country with relatively few licensed fishers to manage. The development of this fishery is reviewed here in a meta‐analysis of catches from 1991 to 2011. The fishery expanded to replace high‐value teatfish species (Holothuria whitmaei and H. fuscogilva), fished heavily in initial stages of the fishery, with newly commercialized medium‐value species such as burying blackfish (Actinopyga spinea) and curryfish (Stichopus herrmanni). These two species now constitute 80% of total catch. The annual average catch of burying blackfish was 208 tonnes years 2004–11 and curryfish catches increased rapidly at an average annual pace of 200% from 2007–11. This serial harvest pattern occurred in the absence of baseline studies and without independent resource assessments, information required to inform relevant harvest predictions and to determine fishery impacts. This situation does not support ecologically relevant and adaptive decision‐making in management and the unfolding catch patterns in the GBRMP follow those in low‐income developing countries. The missing knowledge and lack of data serve as arguments to support precautionary reductions in harvests and extending fallow periods in fishing zones.     

汉阴县2014年油菜菌核病发生特点原因及对策

油菜菌核病是汉阴县油菜生产上的主要病害,2014年汉阴县油菜菌核病具有发生面广,危害严重等特点。通过调查分析油菜盛花期阴雨偏多是造成2014年油菜菌核病大发生的主因;长期连作,菌源充足,田间管理不到位,农户疏于防治均是造成今年菌核病偏重发生的原因。农业部门加强监测预警,从选用抗耐病品种,加强田间管理,提高油菜自身抗病能力,重点加强初花期至盛花期的药剂防治工作,以减轻或控制来年菌核病的危害程度。     

苹果种质资源果实轮纹病抗性的评价

利用5个不同来源的苹果轮纹病菌株,对279份苹果种质资源的果实抗病性进行室内接种鉴定。结果表明：不同种质资源在果实的发病率、潜伏期和病斑大小上均存在极显著差异;同一种质资源分别接种5种轮纹病菌,在发病率、潜伏期和病斑大小上也存在显著差异。对抗病性指标进行相关性分析,多数菌株的各个抗病指标间都存在显著相关性。通过综合抗性筛选,发现‘珍宝’、‘金沙依拉姆’和‘红玉’为高抗材料;‘詹姆斯格里斯’、‘红夏’‘耍红’、‘伊朗桃苹’‘超等蔷薇’和‘极早红’为高感材料。     

Parameter optimized Morlet wavelet de noising method based on cross validation method

A new de noising method based on parameter optimized Morlet wavelet is put forward. The Morlet wavelet is chosen as the mother wavelet because its shape is similar to the mechanical shock signals. The mother Morlet wavelet is improved by adding two parameters which decide the shape of the mother wavelet in time domain. The added parameters and the appropriate scale parameter for the wavelet transformation are designed by the cross validation method. Finally, the useful components of the signal can be obtained by the improved Morlet wavelet de noising method. The gear fault diagnosis experimental result shows that the proposed method has a good de nosing performance and it is effective in fault feature extraction.     

十一种杀菌剂防治马铃薯晚疫病的适宜施用时期

为了明确当前市场上具有代表性的11种防治马铃薯晚疫病杀菌剂的适宜施用时期,采用人工接种马铃薯叶片的方法,测定了其中5种药剂在接种晚疫病菌前10 d内不同时间施用的预防效果和其中7种药剂在接种后24 h内不同时间施用的治疗效果。结果显示:在保证良好防治效果的前提下,药剂在病原菌接种前保护性施用的适宜时期比在接种后治疗性施用的适宜时期要长。在测试浓度下,接种前5种供试药剂保持100%防治效果的适宜施用时期为接种前3~10 d;而接种后7种供试药剂保持相同防效的适宜施用时期仅为接种后6~12 h,在生产实际中难以操作。研究结果说明,在田间马铃薯晚疫病的化学防治中,为了取得良好防治效果,每次用药均应在病菌侵入之前采用保护性施用,尽量避免在病菌侵入之后进行治疗性施用。