真菌寄生大豆孢囊线虫的初步研究

从山东省高密县、胶州市及江苏省沛县5个采集点的大豆孢囊线虫中,共分离出110个真菌菌株。优势真菌是镰刀菌,其它为柱孢菌、弯孢霉菌和一种子囊菌。真菌的出现机率平均为44％。在洋菜平板上测定,菌株对该线虫卵,均有不同程度的重寄生能力,其中茄病镰刀菌高达49％。该菌和柱孢菌的分生孢子萌发后可直接穿透卵壁,卵的内含物完全被其粗短的菌丝体取代。     

昆虫线虫抑制植物线虫的机理研究进展

斯氏科(Steinernematidae)、异小杆科(Heterorhabditidae)、索科(Mermithidae)和小杆科(Rhabditidae)线虫为几类较有生物防治前景的昆虫线虫。一些昆虫线虫除了能够有效地防治有害昆虫,还具有抑制植物线虫的作用,本课题组研究发现小杆科、小杆属Rhabditis(Oscheius)的某些昆虫线虫品系也有抑制植物线虫的作用。国内在这方面报道很少,国外许多线虫研究者自20世纪80年代以来有过一些研究。本文着重报道昆虫线虫抑制植物线虫的作用机理研究进展、植物线虫的生物防治途径和昆虫线虫的应用范围。     

用喷雾器喷施线虫对其存活和侵染力的影响

试验表明,应用高压机动喷雾机喷施线虫,防治桃小食心虫,在每平方厘米10～20公斤压力下,对线虫的存活、侵染力和寄生强度,均无明显影响。     

Host suitability of Vitis rootstocks to root‐knot nematodes (Meloidogyne spp.) and the dagger nematode Xiphinema index,and plant damage caused by infections

The host suitability of commercial Vitis rootstocks commonly used in Spain (161‐49C, 41B, 1103P, 110R, 140Ru and SO4) to root‐knot nematodes (Meloidogyne arenaria, M. incognita, M. javanica) and Xiphinema index, and damage caused by nematode infection were determined under controlled conditions. The three root‐knot nematodes reproduced with a rate higher than one in all rootstocks, indicating that they are suitable hosts for these nematodes. Growth of rootstocks infected with the root‐knot nematodes was less vigorous than that of nematode‐uninfected controls in the majority of the rootstocks studied. Root infection resulted in moderate to severe root galling in all rootstocks. The shoot and main stem diameters appeared to be the most sensitive variables of damage caused by infection by Meloidogyne spp., with reduction rates from 36% and 53% in 161‐49C to 57% and 66% in 140Ru, respectively. The shoot height was not significantly affected by the root‐knot nematodes and the root fresh weight generally increased as a consequence of intensive galling. The nematode X. index caused significant root damage with a reproduction factor higher than one in all rootstocks. However, reproduction factor was significantly influenced by the rootstock and significantly decreased by about 12‐fold (5·7 to 18·1‐fold) with the increase in inoculum density from 100 to 1000 nematodes per plant. The root dry weight was reduced by X. index infections, and was the plant growth variable most affected by the nematode infection in all rootstocks at both inoculum densities. Meloidogyne arenaria, M. incognita, M. javanica and X. index, prevalent in many world vineyards, are all shown to have a damaging effect on the six tested rootstocks.     

花生种质资源对花生根结线虫病的抗性鉴定

 1987~1991年,搜集国内外花生种质资源共4189份,经过自然病田及人工病圃等抗性鉴定研究,从中筛选出高抗资源2份,中抗资源3份,耐病资源5份及特异株90株,为抗病育种提供了优异抗源材料,并为抗性机制及遗传规律研究提供了初步基础。     

用转基因方法进行抗线虫农作物育种的研究进展

在许多农作物中,植物寄生线虫引起重大损失。有幸的是,某些植物对线虫有抗性,而且存在于栽培种和其近亲野生种中的抗性基因,可以用分子标记方法建立图谱。标记辅助的选择方法已广泛应用于育种工作中,两种抗线虫的基因已经通过定位克隆技术分离出来,并成功地在栽培作物中得到表达。建立线虫抗性的另一个方法是将具有杀线剂效应的基因导入植物中,该方法也已取得了一些进展。     

用转基因方法进行抗线虫农作物育种的研究进展

在许多农作物中,植物寄生线虫引起重大损失。有幸的是,某些植物对线虫有抗性,而且存在于栽培种和其近亲野生种中的抗性基因,可以用分子标记方法建立图谱。标记辅助的选择方法已广泛应用于育种工作中,两种抗线虫的基因已经通过定位克隆技术分离出来,并成功地在栽培作物中得到表达。建立线虫抗性的另一个方法是将具有杀线剂效应的基因导入植物中,该方法也已取得了一些进展。     

Screening of chemical attractants for second-stage juveniles of Meloidogyne species on agar plates

The attractiveness of 60 aromatic compounds, mainly carboxylic acids, alcohols, aldehydes, and phenols, to second-stage juveniles (J2) of four Meloidogyne species (M. hapla, M. incognita, M. javanica, and M. marylandi) was evaluated based on the relative density of J2 attracted to a test compound on an agar plate in an 8.5-cm Petri dish. Three types of nematode responses were observed in the single-compound assays: attraction, in which J2 were attracted to test compounds; concentration-dependent attraction, in which J2 were attracted to the zone located 1–2 cm from test compounds; and no response. None of the test compounds effectively attracted M. incognita or repelled J2 of any species. Thirty-five compounds attracted J2 of at least one of the other three nematode species. Highly effective attractants were trans-cinnamic acid, salicylic acid, 4′-hydroxy-3′-methoxyacetophenone, o-vanillin, carvacrol, 3-methoxybenzyl alcohol, 2-methoxycinnamaldehyde, trans-p-methoxycinnamaldehyde, 4-methoxy-3-methylbenzaldehyde, 2-methoxy-4-propenylphenol, and thymol. Salicylic acid dissolved in the agar reduced the attraction of M. marylandi J2 to salicylic acid and to o-vanillin. Two- and three-compound assays revealed differences in attractiveness to M. marylandi J2 between or among structural isomers of the attractants. o-Vanillin and salicylic acid were much more attractive to M. marylandi than vanillin and the two isomers of salicylic acid, respectively. It is not clear whether nematodes utilize the attractants found in the study for locating hosts in nature, but the attractants may have potential for use in nematode control.     

中华六索线虫生态学研究

本文对中华六索线虫的生物学及一些基本的生态学方面进行了研究。提出了六索线虫寄生粘虫的主动侵染的有关证据。研究结果还表明其群体在土壤中的栖息深度主要在20—40cm处,没有明显的季节性垂直迁移;土壤含水过多,偏酸偏碱以及盐渍化等对其存活都有明显的影响;对寄生率影响较明显的为侵染期的降雨日数和前一年线虫脱出高峰期的露日数。     

Nematicidal efficacy of MCW‐2, a new nematicide of the fluoroalkenyl group,against the root‐knot nematode Meloidogyne javanica

BACKGROUND: The small number of available nematicides and restrictions on the use of non‐fumigant nematicides owing to high toxicity to human and non‐target organisms hinder effective nematode control. The nematicidal efficacy of MCW‐2, a new nematicide of the fluoroalkenyl group, was evaluated against the root‐knot nematode Meloidogyne javanica (Treub.) Chitwood. RESULTS: MCW‐2 showed irreversible nematicidal activity against second‐stage juveniles of M. javanica in vitro, following exposure for 48 h at concentrations as low as 0.5 mg L^?1, in contrast to fenamiphos or cadusafos. When exposed to MCW‐2 for shorter periods, motile juveniles became immobile with time after rinsing in water. MCW‐2 at 8 mg L^?1 inhibited nematode hatching, which, however, recovered after rinsing in water. In pot and plot experiments, 0.5 mg MCW‐2 L^?1 soil and 2 kg MCW‐2 ha^?1, respectively, controlled M. javanica similarly to or better than fenamiphos or cadusafos at the same concentrations or at their recommended doses. In the soil, the nematicidal activity of MCW‐2 was less persistent than that of fenamiphos. CONCLUSION: MCW‐2 has potential to be used as a new non‐fumigant nematicide that probably has a novel mode of action. Copyright © 2009 Society of Chemical Industry     

连作和轮作对大豆胞囊线虫群体数量及土壤线虫群落结构的影响

大豆胞囊线虫Heterodera glycinesIchinohe病害是大豆生产中的毁灭性病害,对世界大豆生产造成重大损失。采用根染色法和常规土壤线虫分类鉴定技术研究了连作和轮作两种耕作方式下大豆胞囊线虫群体数量和土壤线虫群落结构的变化。结果表明,连作使大豆田土壤中胞囊和根系上各龄期胞囊线虫数量显著增加(95.6→335.5),而轮作积累很少(10.3→31.8),感病品种中J2的侵入数量决定了大豆胞囊线虫形成胞囊的数量(22.8→95.6,129.4→335.5)。玉米-玉米-大豆的轮作方式使胞囊积累最少(10.3)。轮作大豆田土壤线虫总数高于连作,主要由于轮作大豆田土壤线虫的优势属Helicotylenchus和优势营养类群植物寄生线虫PP的相对丰度高于连作,但大豆胞囊线虫的相对丰度正相反,连作(33.65%)高于轮作(0.91%),说明Heterodera glycines可以作为土壤线虫的关键属种用以指示土壤发病的严重程度。研究中重要的优势属和关键属种cp值均为3,说明其繁殖和抗干扰能力比较强。研究证明土壤线虫优势营养类群、优势属种和关键属种可以有效地指示农业土壤健康状况和大豆田的大豆胞囊线虫病害的发生程度。     

连作年限对番茄根围土壤根结线虫二龄幼虫与自由生活线虫数量的影响

 保护地连作是根结线虫为害严重的主要原因,为评估连作年限对根结线虫数量及其与土壤线虫数量关系,选择典型的不同连作时间的保护地(种植番茄),研究番茄生长期间根围土壤不同土层的根结线虫二龄幼虫(second-stage juveniles,J2)与自由生活线虫数量的动态变化。结果表明:根结线虫J2数量随连作年限增加而增多,0和5-year土壤中根结线虫数量少,平均根结线虫数为1.1和2.1条/100g干土,8、10和12-year土壤中根结线虫数量平均值分别为154.9、68.3和861.8条/100g干土;在0~30cm土层,根结线虫J2数量随土层加深而增加,主要分布在20~30cm土层。土壤自由生活线虫数量随土层的增加而增多,连作对自由生活线虫数量无显著影响。0和5-year土壤中根结线虫群体占土壤线虫总数的比例小,属稀有类群,在土壤线虫中处于稳定的群落结构状态。连作8、10和12-year的土壤中根结线虫J2为优势类群,土壤中自由生活线虫数量与根结线虫数量呈现相反的趋势,根结线虫J2占土壤线虫总数的比例增加,自由生活线虫与根结线虫J2数量的比值显著降低(P<0.05)。     

昆虫病原线虫与其他杀虫因子之间相互作用的研究进展

昆虫病原线虫作为生物杀虫剂近年来已被人们所认识，并已广泛应用于防治多种农林害虫。本文介绍了昆虫病原线虫与其他杀虫因子之间相互作用的研究概况。     

Host–parasite relationships of Meloidogyne incognita on spinach

Host–parasite relationships in root-knot disease of spinach caused by Meloidogyne incognita race 1 were studied under glasshouse conditions. Nematode-induced mature galls were large and usually contained one or more females and egg masses with eggs. Feeding sites were characterized by the development of giant cells containing granular cytoplasm and many hypertrophied nuclei. The cytoplasm in these giant cells was aggregated alongside the thickened cell walls. Stelar tissues within galls appeared disorganized. The relationship between initial nematode population density ( P _i) in a series from 0–128 eggs and second-stage juveniles per cm³ soil and growth of spinach cv. Symphony F₁ seedlings was tested under glasshouse conditions. A Seinhorst model [ y = m  + (1 −  m ) z ^P–T ] was fitted to fresh top- and total plant-weight data for inoculated and control plants. Tolerance limits ( T ) of spinach cv. Symphony F₁ to M. incognita race 1 for fresh top and total plant weights were 0·25 and 0·5 eggs and second-stage juveniles per cm³ soil, respectively. The minimum relative values for fresh top and total plant weights were zero in both cases at P _i ≥ 32 eggs and second-stage juveniles per cm³ soil. Root galling was least at low initial population densities and greatest at 16 eggs and second-stage juveniles per cm³ soil. Maximum nematode reproduction rate was 33·1-fold at the lowest P _i.     

Pathogenicity and host‐parasite relationships of the root‐knot nematode Meloidogyne incognita on celery

Pathogenicity and host‐parasite relationships in root‐knot disease of celery (Apium graveolens ) caused by Meloidogyne incognita race 1 were studied under glasshouse conditions. Naturally and artificially infected celery cv. D’elne plants showed severe yellowing and stunting, with heavily deformed and damaged root systems. Nematode‐induced mature galls were spherical and/or ellipsoidal and commonly contained more than one female, males and egg masses with eggs. Feeding sites were characterized by the development of giant cells that contained granular cytoplasm and many hypertrophied nuclei. The cytoplasm of giant cells was aggregated along their thickened cell walls and consequently the vascular tissues within galls appeared disrupted and disorganized. The relationship between initial nematode population density (Pi) and growth of celery plants was tested in glasshouse experiments with inoculum levels that varied from 0 to 512 eggs and second‐stage juveniles (J₂) mL^?1 soil. Seinhorst's model y = m + (1 – m)z^P–T was fitted to height and top fresh weight data of the inoculated and control plants. The tolerance limit with respect to plant height and fresh top weight of celery to M. incognita race 1 was estimated as 0·15 eggs and J₂ mL^?1 soil. The minimum relative values (m) for plant height and top fresh weight were 0·37 and 0·35, respectively, at Pi ≥ 16 eggs and J₂ mL^?1 soil. The maximum nematode reproduction rate (Pf/Pi) was 407·6 at an initial population density (Pi) of 4 eggs and J₂ mL^?1 soil.     

福建省花生根部寄生线虫种类鉴定

从福建省花生(Arachis hypogaea Linn.)根部及根际土壤中共分离鉴定出11种植物寄生线虫:肾状肾形线虫(Rotylenchulus reniformis)、咖啡短体线虫(Pratylenchus coffeae)、饰环矮化线虫(Tylenchorhynchus annula-tus)、装饰小环线虫(Criconemella ornata)、双宫螺旋线虫(Helicotylenchus dihystera)、食菌茎线虫(Ditylenchusmyceliophagus)、蘑菇滑刃线虫(Aphlenchoides composticola)、燕麦真滑刃线虫(Aphelenchus avenae)、广东杆垫刃线虫(Rhabdotylenchus guangdongensis)、丝尾垫刃线虫(Filenchus sp.)和根结线虫(Meloidogyne sp.)。其中肾状肾形线虫、咖啡短体线虫、装饰小环线虫和根结线虫为花生的重要寄生线虫。     

嗜线虫杆菌接菌量对小卷蛾线虫产量的影响

本文报道了嗜线虫杆菌Ａ２４品系不同培养时间和接菌量对小卷蛾线虫产量的影响。结果表明：共生菌不同培养时间１６、２０、２４、２８和３２小时对线虫产量没有影响；在其它培养条件相同的情况下，接菌量大，线虫产量高，但每８０ｇ线虫培养基接菌量达到３．３６×１０９时，线虫产量不再随着接菌量的增加而增加，而是稳定在一定的水平。本实验的结果表明：每８０ｇ线虫培养基对共生菌需求量的临界值为３．３６×１０９个细胞。