The role of ectomycorrhizal fungi in alleviating pine decline in semiarid sandy soil of northern China: an experimental approach

The decline of Mongolian pine (Pinus sylvestris var. mongolica) trees on sandy land in northern China has caused serious ecological concerns. Mongolian pine is an ectomycorrhizal fungus (ECM)-dependent species. Three ECM species (Boletus sp., Lactarius deliciosus and L.sp.) were collected from Mongolian pine plantation stands to test their beneficial effects on Mongolian pine seedlings and their responses to environmental factors such as pH, drought stress and temperature. The results indicated that ECM inoculation significantly increased the rate of ECM colonization and the length of seedling shoots. The three ECM could grow in a pH range from 4 to 7, but did not grow under heavy drought stress (?1.53 MPa). High temperatures (over 37 °C) caused death of ECM. When related to soil pH, soil water content and temperature in the Mongolian pine plantations, water conditions and temperature were unfavorable for ECM growth in surface soil, but suitable in deeper soil. Therefore, it was concluded that the failure of natural regeneration in Mongolian pine plantations might be influenced by the lack of ECM in the surface soil because of high temperatures causing ECM death. Moreover, the majority of the root area is distributed in deeper soil, which alleviates the stresses on ECM development and arrests pine decline; this is beneficial for tree growth.     

A preliminary study of water use strategy of desert plants in Dunhuang,China

Water is a restrictive factor for plant growth and ecosystem stability in arid and semiarid areas. The dynamics of water availability in soils and water use by plants are consequently critical to ecosystem functions, e.g. maintaining a high resistance to the changing climate. Plant water use strategies, including water-use efficiency(WUE) and the main water source that a plant species utilizes, play an important role in the evaluation of stability and sustainability of a plantation. The water use strategies of desert plants(Tamarix chinensis, Alhagi sparsifolia, Elaeagnus angustifolia, Sophora alopecuroides, Bassia dasyphylla and Nitraria sphaerocarpa) in three different habitats(saline land, sandy land and Gobi) in Dunhuang(located in the typical arid area of northwestern China) were studied. The stable isotope of oxygen was used to determine the main water source and leaf carbon isotope discrimination was used to estimate the long-term WUE of plant species in the summer of 2010. The results suggest that: 1) the studied desert plants took up soil water below the depth of 80 cm; 2) T. chinensis in the three habitats used deeper soil water and T. chinensis in the Gobi site had higher WUE than those in the saline land and the sandy land. The results indicated that desert plants in Dunhuang depended on stable water source and maintained high WUE to survive in water limited environments.     

种衣剂中不同浓度杀虫剂成分对玉米苗期生长的安全性评价

选择克百威、丙硫克百威和丁硫克百威3种杀虫剂作为种衣剂有效杀虫成分,每种杀虫剂设置1%、2%、3%、…10%共10种浓度梯度,春天播种期进行玉米包衣播种,20 d后调查苗期植株的根长、根数、叶数和株高,验证3种杀虫剂不同浓度对玉米苗期的生长安全性。结果表明：在10%浓度以下,3种杀虫剂进行种子包衣处理,玉米苗期生长均未产生药害,植株生长正常。     

Real‐time PCR detection of Erwinia amylovora on blossoms correlates with subsequent fire blight incidence

Fire blight is the most devastating bacterial disease of rosaceous plants. Forecasting fire blight infections is important to allow for countermeasures that reduce economic damage in pome fruit production. Current computerized forecasting models are solely based on physical factors such as temperature and moisture, but not on the actual presence of the pathogen Erwinia amylovora. Although the inoculum concentration is considered to be crucial for infection and disease outbreak, most current approaches used for identification of fire blight inoculum including morphological, biochemical, serological, and DNA‐based methods are nonquantitative. Based on a real‐time PCR approach previously published, an improved protocol to be used directly on whole bacteria in the field is described. The method allows for early detection and quantification of the pathogen prior to the occurrence of first symptoms. There is a clear correlation between bacterial abundance and subsequent disease development. However, in some cases, no disease symptoms could be observed despite a pathogen load of up to 3·4 × 10⁶ cells per blossom. Integration of the amount of pathogen detected into refined prediction algorithms may allow for the improvement of applied forecasting models, finally permitting a better abatement of fire blight.     

壬菌铜30%微乳剂防治葡萄霜霉病田间药效试验

试验表明壬菌铜30%微乳剂对葡萄霜霉病有很好的防治效果,使用浓度为200、300mg/kg时,对葡萄霜霉病的防治效果分别为79.9%、85.3%,与氢氧化铜46%水分散粒剂230mg/kg、烯酰吗啉40%悬浮剂250mg/kg处理的防效相当,且耐雨水冲刷,持效期长,价格低廉,值得推广使用。     

西双版纳橡胶盔蚧天敌调查

通过对西双版纳州各大国有农场(景洪、勐养、勐捧、勐腊、橄榄坝、东风)、民营胶园(三达山、嘎栋、嘎洒、勐罕)及西双版纳热带花卉园内幼林地的调查,初步了解到橡胶盔蚧的天敌31种,其中云南省天敌新记录9种,分为2个纲、7个目、11个科,其中优势种为普通草蛉、川上座壳孢和寄生蜂,分别占天敌总量的26.43%、32.35%和27.48%。比较有利用前景的为普通草蛉和寄生蜂。     

3株来源于青稞白酒糟醅的生防菌株鉴定及其生物活性

为寻找高效安全且来源于生物源的除草活性物质,以此为先导化合物开发生物源除草剂。从青稞白酒糟醅中分离到的菌株中筛选到3株高效除草活性菌株,经形态特征和分子生物学鉴定后,确定JZ2?1?2为多粘类芽孢杆菌,JZ2?4?5、JZ2?5?2为枯草芽孢杆菌。3株芽孢杆菌的发酵液对供试禾本科杂草野燕麦的种子萌发具有抑制作用,同时对其幼苗发育影响明显,对野燕麦幼苗根长抑制率分别为92.48%、100.00%、100.00%。枯草芽孢杆菌JZ2?4?5发酵液通过茎叶喷施后,盆栽野燕麦植株7 d后大部分死亡,JZ2?5?2、JZ2?1?2对野燕麦防除效果次之。野燕麦叶片的相对含水量、叶绿素含量均有显著降低,MDA含量和SOD酶活性也变化明显。同时证明了3株芽孢杆菌属菌株对油菜菌核病原菌具有较好的拮抗作用。作物安全性结果表明,3株芽孢杆菌属菌株对小麦、青稞安全,对油菜、蚕豆风险高。综上所述,从青稞白酒糟醅中分离到的多粘类芽孢杆菌JZ2?1?2,枯草芽孢杆菌JZ2?4?5、JZ2?5?2具有作为麦田生物源除草剂开发的潜力。     

急性感染猪瘟病毒猪体外排毒规律的观察

为研究CSFV感染后在体外的传播途径、排毒规律,针对CSFV基因组设计了一对引物和一条探针,建立了一套CSFV荧光定量PCR(FQ-PCR)检测方法,并以质粒为标准品得到扩增标准曲线.对18个CSFV阳性质控样本检测全阳性,6个CSFV阴性质控样本检测全阴性,显示良好敏感性和特异性.应用此方法对石门株感染的16头60日龄长白猪和1头阴性对照猪的粪便、尿液、眼分泌物和唾液中病毒含量进行了动态测定,结果表明从感染后第1天到频死前第8天,粪便中均能检测出病毒;尿液和眼分泌物至少能从第3天,唾液从第4天开始检测出病毒,且病毒含量呈增加趋势.本研究对急性感染猪瘟病毒猪体外排毒规律进行了系统研究,为弄清CSFV感染病程、致病机理及临床诊断奠定了重要理论基础.     

链霉菌NND－52菌株及其次生代谢物的鉴定

对从土壤中分离的ＮＮＤ－５２菌株的形态、培养特征、生理生化特征及其拮抗性进行综合分析，确定该菌株属于吸水链霉菌。该菌表现了对水稻纹枯菌、小麦赤霉菌等植物病原菌的抑制活性。发酵上清液对稗草、马唐等杂草显示除草活性。上清液中活性成分经提纯结晶并经紫外吸收光谱、红外吸收光谱、核磁共振波谱、质谱检测及元素分析，证实其结构为除莠霉素Ａ（ｈｅｒｂｉｍｙｃｉｎＡ）。ＮＮＤ－５２菌株的菌丝体干粉添加于饲料中喂鸡，表现出抗鸡球虫并使鸡增重的效果。