北京春季沙尘天气特征和预报

根据北京地区资料分析了沙尘的年代变化、月变化,春季是沙尘天气的高发期并以浮尘和扬沙为主。造成沙尘天气的冷空气主要有三条路径,它与蒙古气旋、冷锋、高空急流等大尺度天气系统紧密相连。     

Effects of straw and silicon soil amendments on some foliar and stem-base diseases in pot-grown winter wheat

Four foliar and two stem-base pathogens were inoculated onto wheat plants grown in different substrates in pot experiments. Soils from four different UK locations were each treated in three ways: (i) straw incorporated in the field at 10 t ha⁻¹ several months previously; (ii) silicon fertilization at 100 mg L⁻¹ during the experiment; and (iii) no amendments. A sand and vermiculite mix was used with and without silicon amendment. The silicon treatment increased plant silica concentrations in all experiments, but incorporating straw was not associated with raised plant silica concentrations. Blumeria graminis and Puccinia recondita were inoculated by shaking infected plants over the test plants, followed by suitable humid periods. The silicon treatment reduced powdery mildew ( B. graminis ) substantially in sand and vermiculite and in two of the soils, but there were no effects on the slight infection by brown rust ( P. recondita ). Phaeosphaeria nodorum and Mycosphaerella graminicola were inoculated as conidial suspensions. Leaf spot caused by P. nodorum was reduced in silicon-amended sand and vermiculite; soil was not tested. Symptoms of septoria leaf blotch caused by M. graminicola were reduced by silicon amendment in a severely infected sand and vermiculite experiment but not in soil or a slightly infected sand and vermiculite experiment. Oculimacula yallundae (eyespot) and Fusarium culmorum (brown foot rot) were inoculated as agar plugs on the stem base. Severity of O. yallundae was reduced by silicon amendment of two of the soils but not sand and vermiculite; brown foot rot symptoms caused by F. culmorum were unaffected by silicon amendment. The straw treatment reduced severity of powdery mildew but did not detectably affect the other pathogens. Both straw and silicon treatments appeared to increase plant resistance to all diseases only under high disease pressure.     

A mutation confers Monochoria vaginalis resistance to sulfonylureas that target acetolactate synthase

Acetolactate synthase (ALS) is the target enzyme for four distinct families of compounds: sulfonylureas (SUs), imidazolinones, triazolopyrimidine sulfonanilides, and pyrimidinyl oxybenzoates. We cloned and sequenced the fragments encoding ALS genes from biotypes of Monochoria vaginalis susceptible (S) and resistant (R) to SU-herbicides. The nucleotide sequences of the 39 bp Domain A region for R M. vaginalis biotype differed from that of the S biotype by a single nucleotide substitution at variable Pro codon of Domain A (CCT to TCT), predicting a Pro in the S but a Ser in the R biotype. No nucleotide differences between S and R M. vaginalis were observed in Domain D. We suggest that the amino acid substitution at Domain A region is responsible for resistance to SU-herbicides in M. vaginalis collected from Ushiku City, Ibaraki Prefecture, Japan.     

2019年湖南省部分地区鸡、鸭、猪源大肠杆菌耐药性调查

旨在调查2019年湖南省部分地区不同来源的大肠杆菌对抗生素的耐药水平,为养殖合理用药提供参考。从4个市畜禽养殖场采集猪、鸡和鸭粪便285份,使用麦康凯琼脂培养基和伊红美蓝培养基对大肠杆菌筛选,利用基质辅助激光解析电离飞行时间质谱进行鉴定,采用微量肉汤稀释法检测16种抗生素对大肠杆菌的最小抑菌浓度(MIC)。共分离出203株大肠杆菌(鸡源146株、鸭源20株和猪源37株),对四环素和氨苄西林耐药率最高,分别达到89.2%和84.7%;对头孢他啶、奥格门丁、黏菌素耐药率较低,分别为2.5%、2.0%和0.5%;所有菌株均对美罗培南敏感。抗3种及以上抗生素的菌株数目占比为87.7%,而仅5.42%的菌株对所有检测的抗生素敏感。另外,来源于减抗示范养殖场的大肠杆菌对大部分抗生素的耐药率,与来源于非减抗养殖场大肠杆菌相比未见显著差异。上述结果表明,湖南省动物源大肠杆菌的耐药水平仍处在较高水平,重视兽药使用管理并持续开展对大肠杆菌的耐药性监测十分必要。     

卷丹转基因体系构建及岷江百合LrCCoAOMT的导入

以卷丹(Lilium lancifolium Thunb.)无菌小鳞片为试材,通过切片处理、优化农杆菌侵染浓度与时间以及重悬液和共培养基成分,构建农杆菌介导的高效遗传转化体系。结果表明,MS+1.5 mg·L^-16-BA+0.5 mg·L^-1 NAA+30 g·L^-1蔗糖是切片芽分化的最佳培养基,添加100 mg·L^-1抗坏血酸能有效抑制褐化并促进不定芽增殖。MS+2.0 mg·L^-1 NAA+30 g·L^-1蔗糖是生根诱导的最佳培养基。抗生素敏感性测试发现,培养基中添加Kan 100 mg·L^-1或Hyg 75 mg·L^-1结合Cef 400 mg·L^-1适宜抗性筛选。GUS染色分析表明,以去除大量元素的改良MS+100μmol·L^-1AS和去除大量元素的改良MS+1.0mg·L^-16-BA+1.0mg·L^-1NAA+100...     

低鱼粉饲料中添加酶解豆粕对凡纳滨对虾生长性能和抗胁迫机能的影响

为研究在养殖过程中降低鱼粉用量的同时保持凡纳滨对虾良好的生长性能和抗逆能力,实验在含10%鱼粉的基础饲料中,分别添加酶解豆粕(PSM) 0%(A)、2.5%(B)、3.5%(C)、4.5%(D)、5.5%(E)制成5组等氮等能饲料,分别投喂初始体质量为(0.45±0.02) g的凡纳滨对虾幼虾8周,检测对虾生长性能及抗胁迫机能。结果显示,8周养殖实验结束后,各实验组对虾的终末体质量为14.65～15.38 g/尾,各组间对虾终末均重、成活率和饲料系数指标均无显著性差异;A组对虾肌肉粗蛋白质含量显著低于其他各实验组;C组、D组和E组对虾肌肉粗脂肪含量显著高于A组;各组间灰分和水分均无显著性差异;D组和E组对虾肝胰腺蛋白酶、淀粉酶、脂肪酶、血清溶菌酶和血清总超氧化物歧化酶活性(T-SOD)均显著高于A组;A组对虾血清丙二醛(MDA)含量显著高于D组和E组。人工急性感染高剂量副溶血性弧菌的胁迫实验中,A组对虾在弧菌感染48和60 h时的累积死亡率均显著高于D组对虾同期的累积死亡率;低剂量副溶血性弧菌人工急性感染后,在凡纳滨对虾鳃组织中检测Toll受体、免疫缺陷(IMD)和溶菌酶3种免疫相关基...     

不同温度下TMV侵染枯斑三生烟的LncRNA差异表达

【目的】筛选不同温度下烟草花叶病毒(Tobacco mosaic virus,TMV)侵染后枯斑三生烟(Nicotiana tabacum var. Samsun NN)差异表达的长链非编码RNA(long non-coding RNA,lncRNA),研究lncRNA在枯斑三生烟抗性反应中的作用。【方法】N基因的温度敏感性使枯斑三生烟在25℃时具备对TMV的抗性、在31℃抗性丧失,在这两个温度条件下对枯斑三生烟接种TMV和磷酸盐缓冲盐水(phosphate buffered saline,PBS),48 h后提取系统叶总RNA,构建链特异性文库后进行深度测序。对测序结果进行过滤后利用HTSeq将有效数据与近缘品种TN90(N. tabacum var. TN90)基因组比对,筛选得到lncRNA后利用FPKM法估计lncRNA的表达水平。通过edgeR筛选差异表达lncRNA(differentially expressed lncRNA,DElncRNA),并利用qRT-PCR技术对这一结果进行验证。通过共定位及共表达分析预测DElncRNA的靶基因,通过参考基因组注释、GO和KE...     

外源海藻糖对高温胁迫下肺形侧耳氧化损伤的缓解效应

高温胁迫影响食用菌的品质和产量,由高温引起的氧化胁迫是导致损伤的主要原因.以肺形侧耳(Pleurotus pulmonarius)热敏感菌株CCMSSC 00494和耐热菌株CCMSSC 00499为试验材料,研究了外源海藻糖对其菌丝体高温胁迫下氧化损伤的缓解效应.结果表明,高温(40℃)胁迫48 h,热敏感菌株中硫代巴比妥酸反应物(TBARS)含量(代表氧化损伤程度)高于耐热菌株.外源海藻糖处理可以显著降低高温胁迫下菌丝体内O2-产生速率、H2O2含量、脂氧合酶(LOX)活性和TBARS含量水平,缓解高温胁迫所引发的氧化损伤.另外,外源海藻糖对超氧化物歧化酶(SOD)活性有保护和提高的作用,对过氧化氢酶(CAT)和抗坏血酸过氧化物酶(APX)活性有抑制作用,对过氧化物酶(POD)活性影响不明显.外源海藻糖对热敏感菌株的保护效应高于耐热菌株.     

优质抗病厚皮甜瓜新品种苏甜2号的选育

苏甜2号为中早熟厚皮甜瓜杂交种。全生育期95d左右,果实发育期约35d。植株长势较强,抗白粉病和蔓枯病,较耐低温,易坐果。果实短椭圆形,果皮白色、光滑无网纹;肉厚3.8～4.2cm,果肉浅绿色,肉质软嫩,具有浓香味,中心可溶性固形物14.7%～16.8%。耐贮运。单果质量1.0～2.0kg,667m2产量2000～2300kg。适于华东地区及气候相似地区保护地栽培。     

脱锻炼期间金叶女贞对冷冻温度与持续时间的响应

以1 a 生金叶女贞苗木为研究材料,通过设置不同的低温水平,维持不同的冷冻时间模拟自然界突发的降温环境,测定其成活率、生长量等指标.结果表明:保定地区温度降至-2～0℃时,不需要对金叶女贞进行防寒措施便可安全度过霜期;但降到-6℃则需要采取必要的保护措施.