烟草根结线虫天敌真菌的分离与鉴定

本文采用３种不同的分离方法，从烟草根结线虫病根及土壤中，分离鉴定出５种捕食线虫真菌，节丛孢属的Ａｒｔｈｒｏｂｏｔｒｙｓｏｌｉｇｏｓｐｏｒａ、Ａ．ｃｌａｄｏｄｅｓ、Ａ．ｍｕｓｉｆｏｒｍｉｓ，单顶孢霉属的Ｍｏｎａｃｒｏｓｐｏｒｉｕｍｌｙｓｉｐａｇａ、Ｍ、ｍｅｇａｌｏｓｐｏｒｕｍ；１种内寄生真菌，轮枝霉属Ｖｅｎｔｉｃｉｌｌｉｕｍｓｐ。     

烟草根结线虫天敌真菌的分离与鉴定

本文采用３种不同的分离方法，从烟草根结线虫病根及土壤中，分离鉴定出５种捕食线虫真菌，节丛孢属的Ａｒｔｈｒｏｂｏｔｒｙｓ ｏｌｉｇｏｓｐｏｒａ， Ａ． ｃｌｃｄｏｄｅｓ，Ａ． ｍｕｓｉｆｏｒｍｉｓ，单顶孢霉属的Ｍｏｎａｃｒｏｓｐｏｒｉｕｍ ｌｙｓｉｐａｇａ，Ｍ，ｍｅｇａｌｏｓｐｏｒｕｍ；１种内寄生真菌，轮枝霉属Ｖｅｒｔｉｃｉｌｌｉｕｍ ｓｐ。     

几种捕食真菌对烟草根结线虫致病力研究初报

本文应用捕食真菌Ａｒｔｈｒｏｂｏｔｒｙｓｏｌｉｇｏｓｐｏｒａ，Ａ．ｍｕｓｉｆｏｒｍｉｓ，Ａ．ｃｌａｄｏｄｅｓ，Ａ．Ｖｅｒｍｉｃｏｌａ，Ｍｏｎａｃｒｏｓｐｏｒｉｕｍｌｙｓｉｐａｇａ，Ｍ．ｍｅｇａｌｏｓｐｏｒｕｍ，Ｍ．ｍｕｔａｂｃｌｅ，对南方根结线虫（Ｍｅｌｏｉｄｏｇｙｎｅｉｎｃｏｇｎｉｔａ）进行了致病力测定和捕食过程观察，结果表明：各菌株对根结线虫二龄幼虫均具有致病性，Ａｒｔｈｒｏｂｏｔｒｙｓ属菌种以三维粘性菌网捕食，Ａ．ｏｌｉｇｏｓｐｏｒａ捕食率最高；Ｍｏｎａｃｒｏｓｐｏｒｉｕｍ属菌种形成粘着孢和非收缩环两种捕食器官。     

几种捕食真菌对烟草根结线虫致病力研究初报

本文应用捕食真菌Ａｒｔｈｒｏｂｏｔｒｙｓ ｏｌｉｇｏｓｐｏｒａ，Ａｍｕｓｉｆｏｒｍｉｓ，Ａ．ｃｌａｄｏｄｅｓ，Ａ．Ｖｅｒｍｉｃｏｌａ，Ｍｏｎａｃｒｏｓｐｏｒｉｕｍ ｌｙｓｉｐａｇａ，Ｍ．ｍｅｇａｌｏｓｐｏｒｕｍ，Ｍ．ｍｕｔａｂｃｌｅ，对南方根结线虫进行了致病力测定和捕食过程观察，结果表明：各菌株对根结线虫二龄幼虫均具有致病性，Ａｒｔｈｒｏｂｏｔｒｙｓ属菌种以三维粘性菌网捕食，Ａ．ｏｌｉｇｏｓｐｏｒ     

木霉菌株TSP-1对烟草根结线虫卵的寄生性试验

为了筛选烟草根结线虫病的优良生防菌株,测定了木霉菌株TSP-1对烟草根结线虫卵的寄生能力.结果显示,接种木霉菌和根结线虫卵悬浮液的处理,其卵粒细胞质变浓、被溶解,二龄幼虫不孵化,而对照培养皿中观测到根结线虫卵逐步发育成熟,最后从培养基平板上孵化出二龄幼虫.表明该木霉菌株能捕食根结线虫虫卵,显示了较强的寄生致病能力,具有生物防治潜力.     

海洋枝顶孢霉BH0531发酵液对根结线虫卵及二龄幼虫的影响

实验以根结线虫的卵、卵囊和二龄幼虫（J2）为研究对象,对海洋枝顶孢霉（Acremonium sp.）BH0531发酵液处理根结线虫不同发育阶段的杀线作用进行了效果评价,并以J2幼虫为靶标,与市面上的灭线磷及阿维菌素的药效进行了初步对比。结果显示,在实验条件下,海洋枝顶孢霉BH0531发酵液对根结线虫卵囊和分散卵的孵化以及J2幼虫的活力均具有明显抑制作用,其对卵囊孵化的抑制作用达40.18%;对分散卵孵化的抑制作用可达84.28%;而对J2幼虫的杀线作用最为显著,校正死亡率高达97.41%,高于实验条件下灭线磷及阿维菌素的测定值,在根结线虫的生物防控方面显现出潜在的研究价值。     

海洋枝顶孢霉BH0531对黄瓜根结线虫防治的微生态效应

测定了海洋枝顶孢霉BH0531发酵液在室内离体条件下对根结线虫的杀线效果,分析了盆栽试验条件下对黄瓜根结线虫指数、减退率及对土壤中微生物数量的影响。结果表明,发酵原液浓缩1倍时,其对根结线虫的校正死亡率高达96.2%;虫口减退率达到71.21%;发酵液对土壤中细菌和放线菌数量均有促进作用,细菌和放线菌数量分别最高达到1.24×108 CFU/mL及1.56×106 CFU/mL,而对真菌则表现出高浓度时的抑制作用,高浓度组真菌由原来的3.12×104 CFU/mL减少至8.67×103 CFU/mL;随着时间的延长,促进作用减弱,但对真菌的抑制作用未减弱。菌株BH0531发酵液可通过杀线作用、促进细菌和放线菌生长、以及降低土壤真菌化程度等微生态效应来实现对黄瓜根结线虫病的防治作用。     

烟草根结线虫生防菌限制性片断长度多态性(RFLP)分析

利用PCR-RFLP方法对烟草根结线虫生防菌单顶孢属进行了系统发育研究。以ITS₁和ITS₄为引物对该属12种14个菌株的核糖体DNA转录间区(ITS)进行了PCR扩增,4种内切酶(AluⅠ、HaeⅢ、HpaⅡ、TaqⅠ)酶切。结果表明,该属的ITS区长度没有明显差异,其长度范围在608~675之间。酶切图谱能体现不同种间的多态性,根据4种内切酶酶切结果,利用UPGMA法构建的单顶孢属分子系统树,基本体现了属内不同种间的亲缘关系,从分子水平证明了单顶孢属形态分类上的合理性      

食蚜瘿蚊对烟蚜的捕食作用

为研究食蚜瘿蚊不同龄期幼虫对不同龄期烟蚜的捕食能力,通过室内试验评估不同龄期食蚜瘿蚊幼虫的捕食功能反应和食蚜瘿蚊3龄幼虫对不同龄期烟蚜的种内干扰作用。结果表明,食蚜瘿蚊幼虫对不同龄期烟蚜的捕食功能反应均为Ⅱ型,其中2龄食蚜瘿蚊幼虫对1~2龄烟蚜的处理时间短（2.0525 h）,理论最大捕食量最大（11.69头）;3龄食蚜瘿蚊幼虫对不同龄期烟蚜的控制作用均强于2龄食蚜瘿蚊幼虫,对高龄烟蚜（3~4龄）的控制效果最为明显;食蚜瘿蚊3龄幼虫对不同龄期烟蚜的日均捕食量随着食蚜瘿蚊密度的增加而显著增大,但平均捕食率随着食蚜瘿蚊密度的增加而逐渐减小。食蚜瘿蚊捕食不同龄期烟蚜的种内干扰作用不同,干扰程度为1~2龄（0.76） > 4龄（0.64） > 3龄（0.57）。因此,食蚜瘿蚊对烟蚜的控制潜能较大,是一种可应用的蚜虫天敌。     

影响四川凉山地区烟草根结线虫病发生的关键因子分析

  目的  解析影响四川省凉山州会理县烟草根结线虫病发生的关键土壤因子, 为烟草根结线虫病防控提供理论支撑。  方法  采集并分析凉山州会理县烟草移栽前根结线虫病发病和未发病土壤的理化性质、二龄线虫数、土壤细菌群落结构和真菌群落结构。  结果  (1) 烟草移栽前, 发病土壤中南方根结线虫二龄线虫数显著高于未发病土壤; (2)发病土壤中交换性镁、交换性钙、有效铜含量和pH值显著低于未发病土壤, 与土壤二龄线虫数呈显著负相关; (3)发病土壤中芽单胞菌属(Gemmatimonas)、类诺卡氏菌属(Nocardioides)、真菌镰刀菌属(Fusarium)和赤霉菌属(Gibbererlla)等关键微生物类群丰度显著偏低, 与土壤二龄线虫数呈显著负相关, 与土壤理化性质存在明显相关性。  结论  移栽前土壤交换性镁、交换性钙、有效铜含量和pH值偏低可能引起土壤中关键微生物丰度降低、二龄线虫数增加, 进而加重烟草根结线虫病的发生。      

常见胶种对台湾桤木椭圆榫接合性能的影响

台湾桤木是生产家具和木制品的优质速生材。以四川引种台湾桤木椭圆榫为研究对象,使用5种常用胶黏剂进行粘接,研究发现:椭圆榫极限抗拔力差异较大,按极限抗拔力值由大到小排列分别为工业明胶、双组份拼板胶、白乳胶、AB胶、万能胶。工业明胶粘接时极限抗拔力达到最大,平均值为6.189 0 kN,其次为拼板胶和白乳胶,平均值分别为6.110 1 kN、5.637 3 kN。由于白乳胶成本较低,使用方法简单,接合性能接近工业明胶与拼板胶且优于AB胶与万能胶,是台湾桤木家具生产制造中椭圆榫接合的优选胶种。     

Variations in the tensile adhesive strength of meat-myosin junctions due to test configurations

A model system of two thick slices of beef M. semitendinosus stuck together with a crude myosin preparation and cooked to 80°C for 1 h has been used to show the effects of testing configuration on the tensile adhesive strength (TAS) of the meat-myosin junction. TAS decreased with increasing cross-sectional area in a square cross-sectional geometry, but increasing just one dimension of a rectangular cross-section resulted in smaller, often insignificant, decreases in TAS. A hypothesis based on differences in stress distributions over the area of the adhesive joint was proposed to explain this. TAS was found to increase with increasing deformation rate, in accordance with the usual behaviour of viscoelastic materials. TAS was found to be approximately three times higher when muscle fibres in both the meat pieces forming the joint were at right angles to the junction than when one or both meat pieces contained fibres running parallel to the adhesive junction; this latter orientation, being the weaker, is therefore proposed to be the orientation that determines the initial fracture of a meat product, hence its textural properties.     

Feasibility of glued laminated timber beams with tropical hardwoods

A feasibility study of glulam was carried out in French Guiana using local wood species. The aim was to determine gluing parameters affording satisfactory behaviour to manufactured glulam in a tropical climate. Three abundant wood species, with special properties, were selected for the study and resorcinol–phenol–formaldehyde resin was used for bonding. Three industrial parameters were considered: adhesive spread rate, closed assembly time and gluing pressure. Delamination and shearing tests were carried out in accordance with European Standards. The tests revealed the influence of wood properties and manufacturing parameters on joint resistance. In fact, the results showed that specific gravity and the shrinkage coefficient greatly influenced the gluing step. Indeed, wood with a medium specific gravity needed more adhesive and more pressure than wood with a high specific gravity. In addition, planing and lamella thickness were found to affect glue joint resistance.     

A semi-automatic method to determine the wood failure percentage on shear test specimens

An alternative method to quantitatively determine the wood failure percentage on shear test specimens was developed, experimentally tested and successfully applied to specimens with typical combinations of adhesive types and wood species used by the glulam industry in Switzerland. The method consists of a staining technique for a better differentiation of wood fibers and adhesive, and an image processing procedure for a standardized estimation of the fractured surface ratio covered by wood fibers and adhesive, respectively. The semi-automatic method allows for a more objective determination of wood failure percentage and is suitable for quality control in the glulam industry.     

Comparison of trapping efficacy for Lasioderma serricorne (F.) adults with electric, pheromone, food attractant and control-adhesive traps

During July, August, September and October 1997, in three tobacco stores in the area of Thessaloniki, four types of adhesive traps: electric (black light), pheromone (serricornin and anhydroserricornin), food attractant and control, were used for trapping Lasioderma serricorne (F.) (Coleoptera: Anobiidae). All traps had the same adhesive area based on 29.5×21 cm² polyethylene sheets. Five replicate comparisons of the four trap types took place. The electric trap caught 8912, the pheromone trap 6608, the food attractant trap 1974 and the control 1231 L. serricorne adults. The electric adhesive trap was significantly more effective than the other traps and the control. The electric trap captured a smaller number of male adults than the pheromone trap but many more females. The ratio between female and male adults was 60.15 : 39.84 for the electric trap, 8.75 : 91.25 for the pheromone trap, 51.57 : 48.42 for the food attractant trap and 43.41 : 56.58 for the control trap.     

Volatile metal species in coal combustion flue gas

Metals are released in effluents of most of combustion processes and are under intensive regulations. To improve our knowledge of combustion process and their resulting emission of metal to the atmosphere, we have developed an approach allowing usto distinguish between gaseous and particulate state of the elements emitted. This study was conducted on the emission of volatile metallic species emitted from a coal combustion plant where low/medium volatile coal (high-grade ash) was burnt. The occurrence of volatile metal species emission was investigated by cryofocusing sampling procedure and detection using low-temperature packed-column gas chromatography coupled with inductively coupled plasma-mass spectrometry as multielement detector (LT-GC/ICP-MS). Samples were collected in the stack through the routine heated sampling line of the plant downstream from the electrostatic precipitator. The gaseous samples were trapped with a cryogenic device and analyzed by LT-GC/ICP-MS. During the combustion process, seven volatile metal species were detected: three for Se, one for Sn, two for Hg, and one for Cu. Thermodynamic calculations and experimental metal species spiking experiments suggest that the following volatile metal species are present in the flue gas during the combustion process: COSe, CSSe, CSe2, SeCl2, Hg0, HgCl2, CuO-CuSO4 or CuSO4 x H2O, and SnO2 or SnCl2. The quantification of volatile species was compared to results traditionally obtained by standardized impinger-based sampling and analysis techniques recommended for flue gas combustion characterization. Results showed that concentrations obtained with the standard impinger approach are at least 10 times higher than obtained with cryogenic sampling, suggesting the trapping microaerosols in the traditional methods. Total metal concentrations in particles are also reported and discussed.     

Herbicidal Properties of the Antibiotic Monensin

The agricultural antibiotic monensin caused herbicidal injury to 1- to 2-week-old seedlings of seven weed and two crop species when applied at 10⁻⁴ M as a foliar spray in the greenhouse. The non-ionic surfactant tergitol TMN (0·1 ml litre⁻¹) aided foliar absorption of monensin and increased herbicidal injury. Fresh weight reductions ranged from 20 to 75% (compared to control seedings treated with tergitol alone) 65 h after spray application of 10⁻⁴ M monensin with tergitol. When root-fed at 10⁻⁴ M, monensin (without tergitol) caused death in all nine species within 24–72 h after treatment. Monensin supplied to roots at 10⁻⁵ M caused fresh weight reductions in spurred anoda, velvetleaf and prickly sida of 43, 32 and 23%, respectively. Substantial growth effects also occurred in hemp sesbania and sicklepod (33 and 15% reductions in fresh weight, respectively); jimsonweed and johnsongrass had the least fresh weight reductions. Injury included chlorosis, necrosis, desiccation and leaf abscission. Cotton and okra were the most tolerant of all species tested; however, three malvaceous weeds were severely damaged by the compound. When root-fed at 10⁻⁶ M, monensin caused limited injury. Monensin exhibited some degree of selectivity among these crop and weed species and caused greater injury in light-treated than dark-treated plant tissues.     

Occurrence of Fusarium Head Blight species and Fusarium mycotoxins in winter wheat in the Netherlands in 2009

Most recent information on the occurrence of Fusarium Head Blight species and related mycotoxins in wheat grown in the Netherlands dates from 2001. This aim of this study was to investigate the incidence and levels of Fusarium Head Blight species and Fusarium mycotoxins, as well as their possible relationships, in winter wheat cultivated in the Netherlands in 2009. Samples were collected from individual fields of 88 commercial wheat growers. Samples were collected at harvest from 86 fields, and 2 weeks before the expected harvest date from 21 fields. In all, 128 samples, the levels of each of seven Fusarium Head Blight species and of 12 related mycotoxins were quantified. The results showed that F. graminearum was the most frequently observed species at harvest, followed by F. avenaceum and M. nivale. In the pre-harvest samples, only F. graminearum and M. nivale were relevant. The highest incidence and concentrations of mycotoxins were found for deoxynivalenol, followed by zearalenone and beauvericin, both pre-harvest and at harvest. Other toxins frequently found - for the first time in the Netherlands - included T-2 toxin, HT-2 toxin, and moniliformin. The levels of deoxynivalenol were positively related to F. graminearum levels, as well as to zearalenone levels. Other relationships could not be established. The current approach taken in collecting wheat samples and quantifying the presence of Fusarium Head Blight species and related mycotoxins is an efficient method to obtain insight into the occurrence of these species and toxins in wheat grown under natural environmental conditions. It is recommended that this survey be repeated for several years to establish inter-annual variability in both species composition and mycotoxin occurrence.