毛茛科植物提取物添加量对瘤胃微生物体外动态发酵的影响

试验采用活体外产气量法研究毛茛科植物提取物不同添加水平对瘤胃微生物体外发酵的影响。试验采用单因子完全随机化试验设计,以小麦面粉为底物进行体外发酵。瘤胃液供体动物为3头装有永久性瘤胃瘘管的本地黄牛,日粮精料水平为30%(日饲喂2次)。植物提取物添加水平分别为0、100、200、300和400mg/L。结果表明:随着毛茛科植物提取物添加水平的提高,小麦面粉24h的DM消化率呈线性下降(P=0.0002),活体外产气速度呈二次曲线规律降低(P=0.0001),而产气延滞期线性增加(P=0.0001),理论最大产气量呈二次曲线规律增加(P=0.0001)。随着植物提取物添加水平的提高,发酵液pH值呈二次曲线增加(P<0.024)。各培养时间点乳酸含量均较低(P<1mmol/L),且各处理之间差异不显著(P>0.10)。提高植物提取物添加水平导致tVFA产量呈二次曲线趋势下降(P<0.01)。通过本试验可得出:毛茛科植物提取物可以通过降低瘤胃发酵的产气速度、提高发酵液pH值以及乙酸和丁酸摩尔比例来调控瘤胃微生物体外发酵,其中植物提取物的适宜添加水平为200～300mg/L。     

小麦分泌的有机酸影响钙质土中锌的释放

Rhizosphere drives plant uptake of sparingly soluble soil zinc(Zn).An investigation with three experiments was conducted to study organic acid exudation by two contrasting wheat genotypes(Sehar-06 and Vatan),Zn fractions in 10 different calcareous soils from Punjab,Pakistan,and release of different soil Zn fractions by organic acids.The two genotypes differed significantly in biomass production and Zn accumulation under deficient and optimum Zn levels in nutrient solution.At a deficient Zn level,Sehar-06 released more maleic acid in the rhizosphere than Vatan.Ten soils used in the present study had very different physicochemical properties;their total Zn and Zn distribution among different fractions varied significantly.Zinc release behaviour was determined by extracting the soils with 0.005 mol L-1 citric acid or maleic acid.The parabolic diffusion model best described Zn release as a function of time.Parabolic diffusion model fitting indicated more maleic acid-driven than citric acid-driven soil Zn mobility from different fractions.Cumulative Zn release in six consecutive extractions during 24 h ranged from 1.85 to 13.58 mg kg-1 using maleic acid and from 0.37 to 11.84 mg kg-1 using citric acid.In the selected calcareous soils,the results of stepwise linear regression indicated significant release of Fe-Mn oxide-bounded soil Zn by maleic acid and its availability to the Zn-effcient genotype.Hence,release of maleic acid by plants roots played an important role in phytoavailability of Zn from calcareous soils.     

茶树病程相关蛋白基因CsPR5的克隆及表达分析

为探究茶树中病程相关蛋白5(pathogenesis-related protein 5,PR5)在茶树中的功能,采用cDNA末端快速扩增(rapid amplification of cDNA end,RACE)技术克隆了PR5基因的全长;通过荧光定量PCR方法检测了CsPR5在龙井43茶树不同组织部位、植物激素(茉莉酸、乙烯利和水杨酸)处理、茶炭疽病菌Colletotrichum camelliae侵染和小贯小绿叶蝉Empoasca onukii为害后的表达特征。结果表明,CsPR5基因开放阅读框为843 bp,编码281个氨基酸。CsPR5基因在茶树根、茎、嫩叶、花和种子5个组织中的相对表达量分别为0.187、3.093、0.928、0.045和0.012,且五者之间差异显著,主要在茎和叶中表达,其分别为根中相对表达量的16.54倍与4.96倍。水杨酸处理6 h及乙烯利处理6、12 h后,茶树CsPR5基因的相对表达量分别为1.622、2.344和1.845,分别比对照显著上调2.20倍、3.18倍和2.35倍;但是外施茉莉酸对茶树CsPR5基因的相对表达量无影响。茶炭疽病菌侵染显著诱导了茶树CsPR5基因的相对表达量,处理后的相对表达量为1.977,是对照的1.90倍;小贯小绿叶蝉取食显著抑制了其为害部位CsPR5的相对表达量,为7.273,仅为对照的38.80%,但该诱导不具系统性。     

光质对植物离体培养的影响

植物的生长是光形态建成的过程,光质对植物组织培养的一些形态发生过程起重要的调节作用。本文从植物愈伤组织的生长与诱导分化、植物离体器官培养、植物体内内源物质合成3个方面阐述了光质对植物离体培养的影响。     

Characterization of the first two viruses described from wild populations of hammer orchids (Drakaea spp.) in Australia

Sequences representing the genomes of two distinct virus isolates infecting wild plants of two members of the genus Drakaea (hammer orchids) in Western Australia are described. The virus isolated from Drakaea livida has a bipartite genome of 4490 nt (RNA1) and 2905 nt (RNA2) that shares closest sequence and structural similarity to members of the genus Pecluvirus, family Virgaviridae, described from legumes in the Indian subcontinent and West Africa. However, it differs from pecluviruses by lacking a P39 protein on RNA2 and having a cysteine‐rich protein gene located 3′ of the triple gene block protein genes. It is the first peclu‐like virus to be described from Australia. The name Drakaea virus A is proposed (DVA; proposed member of the family Virgaviridae, genus unassigned). The second virus isolate was identified from Drakaea elastica, a species classed as endangered under conservation legislation. The genome sequence of this virus shares closest identity with isolates of Donkey orchid symptomless virus (DOSV; proposed member of the order Tymovirales, family and genus unassigned), a species described previously from wild Caladenia and Diuris orchids in the same region. These viruses are the first to be isolated from wild Drakaea populations and are proposed to have an ancient association with their orchid hosts.     

Causes of death in beef cattle in southern Brazil

We determined the prevalence of diseases and pathogens associated with mortality in beef cattle in the State of Rio Grande do Sul, Brazil, based on pathology laboratory submissions. Postmortem examinations were conducted on 1,277 beef cattle that died between 2008 and 2018. Information regarding age, time of the year, breed, and regional location were analyzed statistically. Most cattle were from the surrounding region of Porto Alegre, and 78.7% of the analyzed cases had diagnostic value. The diagnostic category with most cases was infectious and/or parasitic diseases (60%), followed by toxic and toxicoinfectious (25%). Most cases occurred in the fall. Major disease conditions identified included hemoprotozoal infection (18.2%), rabies (8.2%), and plant intoxications by Senecio spp. (8.5%) and Pteridium arachnoideum (4.6%). Hemoprotozoal infection occurred at a higher frequency in young cattle, mainly in animals up to 1 y old. Intoxication by Senecio spp. was more frequent in cattle 2–3 y old.     

Antimycotic Screening of 58 Malaysian Plants against Plant Pathogens

Ethanolic extracts of 58 Malaysian plants belonging to 24 different families were screened for antifungal activity against seven plant pathogens using the filter paper disc diffusion technique. Two varieties of Piper betle, showed strong activity against all the pathogens tested (Colletotrichum capsici, Fusarium pallidoroseum, Botryodiplodia theobromae, Alternaria alternata, Penicillium citrinum, Phomopsis caricae-papayae and Aspergillus niger), with inhibition diameters significantly (P<0·01) bigger than 2·5 mg ml⁻¹ prochloraz or 10 mg ml⁻¹ clotrimazole. The minimum inhibitory concentrations of the ethanolic extracts of P. betle against these plant pathogens ranged between 0·01 mg ml⁻¹ and 1 mg ml⁻¹. Thirty-four other plants (Kucing gala, Limau batik, Bertholletia excelsa, Bixa orellana, Caesalpinia pulcherrima, Cerbera odollam (fruits and leaves), Colocasia gigantea, Curcuma domestica, Curcuma manga, Derris eliptica, Elephantopus scaber, Eleusine indica, Eugenia polyantha, Euphorbia hirta, Euphorbia tirucalli, Gardenia florida, Hedyotis auricularia, Hibiscus rosa-sinensis, Juniperus chinensis (three varieties), Lawsonia inermis, Lecythis ollaria, Mentha arvensis, Mimusops elengi, Ocimum sanctum, Phyllanthus niruri, Piper nigrum, Piperomia pellucida, Pedilanthus tithymaloides, Polygonum minus, Spondias dulcis, Solanum nigrum, Tinospora tuberculata) showed selective antifungal activity, while 21 species were inactive.     

浅析我国植物检疫领域标准样品研究现状

本文介绍了标准样品研制工作在我国植物检疫领域的发展历程,梳理分析了已发布/立项标准样品的相关数据,结合作者单位在该领域研制标准样品实践经验,对植物检疫领域标准样品存在的问题进行了讨论,以供今后工作参考.     

不同植物生长促进剂对香蕉假植大苗培育的调控作用

采用盆栽试验,在香蕉假植大苗培育过程中分别喷施浓度均为20 mg/L的赤霉素、复硝酚钠、胺鲜酯、α-萘乙酸钠等植物生长促进剂,以喷施清水为对照,通过不同处理假植大苗生长、物质累积及生理指标的分析,明确不同植物生长促进剂在香蕉假植大苗调控的作用。结果表明,本试验采用的4种植物生长促进剂对香蕉假植大苗培育的调控作用不同。与对照相比,叶面分别喷施20mg/L赤霉素、复硝酚钠均能有利于香蕉假植大苗假茎高及叶面积增加,提高叶绿素含量及叶绿素a、b含量,且以上两种植物生长促进剂平均提高叶绿素含量26.46%;喷施20mg/Lα-萘乙酸钠能提高假植苗假茎粗,提高干物质累积量16.11%积及吸氮量9.95%,促进氮磷钾养分吸收。叶面喷施赤霉素、复硝酚钠、α-萘乙酸钠和胺鲜酯均能显著提高香蕉假植大苗抗性,平均降低丙二醛含量14.64%、提高脯氨酸含量64.36%和SOD含量16.74%,且赤霉素还能显著提高POD含量82.13%。