寄生性杂草列当的种类调查及鉴定

列当是一类难以防治的恶性根寄生杂草,目前在番茄、向日葵、烟草和瓜类上危害日益严重。列当的种类多且难以区分,明确列当的种类对制定有效防治措施具有重要意义。从新疆维吾尔自治区、河北省、内蒙古自治区和吉林省4个地区采集了19份列当样品,通过形态观察和DNA条形码技术进行种类鉴定并对其亲缘关系进行讨论。结果发现,寄生于新疆番茄上的列当样品为分枝列当,寄生于河北烟草、河北向日葵和吉林向日葵上的列当样品为弯管列当;在系统发育树中分枝列当与弯管列当有明显的系统进化差异性,弯管列当被分为2个大类群,地理区划明显而与寄主植物无关,采集自河北省的7个样品为1个类群,采自吉林省、新疆维吾尔自治区、内蒙古自治区的8个样品为第2个类群,其中第2类群中采自吉林省的4个样品亲缘关系最近。     

我国新疆焉耆垦区作物轮作种植模式防除列当的有效性研究

本研究以新疆地区危害最严重的向日葵列当和瓜列当为研究对象，通过室内水培试验和室外盆栽模拟轮作试验来探究焉耆垦区轮作模式对两种列当的防除效果。结果表明，室内水培试验中各轮作作物的根系分泌物及萃取相刺激瓜列当种子的萌发率均在20.0%以下，但刺激向日葵列当种子产生的萌发率达到了50.0%以上；室外盆栽模拟轮作试验中，甜菜、小麦、辣椒与加工番茄轮作后，瓜列当的寄生数量未显著降低；但与向日葵轮作后，向日葵列当的寄生数量显著减少了60.0%以上。不同品种甜菜、辣椒和小麦地上部甲醇提取液刺激瓜列当种子的萌发率均低于10.0%，但是刺激向日葵列当种子的萌发率均达70.0%以上。本研究表明新疆焉耆垦区轮作种植模式不能有效防除瓜列当，但模式中的轮作作物均能够有效防除向日葵列当。本研究结果为防除新疆焉耆垦区向日葵列当和瓜列当提供理论依据。     

室内条件下向日葵列当和弯管列当在三种不同寄主上寄生能力的比较

以向日葵列当Orobanche cumana Wallr.和弯管列当O.cernua Loefl.为研究对象,利用已有的室内寄生体系来研究两种列当在向日葵、烟草、番茄3种寄主上的寄生能力。结果表明,向日葵列当在室内条件下不仅能够寄生在向日葵上,同时也可以在烟草与番茄上寄生;但其寄生效率在上述不同的寄主之间存在显著差异,而在相同寄主的不同品系间没有差异。交互侵染的结果表明,在寄主番茄上,弯管列当平均每株寄生的瘤结数量为16.3个,向日葵列当只有2.5个;在寄主向日葵上,向日葵列当的平均寄生瘤结数量为25.2个,弯管列当为27.6个,预示着弯管列当在番茄上寄生效率均显著高于向日葵列当,而在寄主向日葵上,二者寄生效率差异不显著,均能高效寄生在向日葵根系上。上述研究结果将为向日葵列当和弯管列当发生严重地区作物轮作对象的选择提供理论依据。     

水溶性氟乐灵纳米制剂对向日葵列当的毒力及田间药效

向日葵列当Orobanche cumana是一种检疫性恶性寄生杂草。本研究采用透析法制备了一种水溶性氟乐灵纳米制剂(Tf-OR-CC),评价其对向日葵列当的室内毒力和田间药效。种子发芽毒力测定结果表明:在独脚金内酯类似物GR24的诱导下,用5μg/mL Tf-OR-CC处理向日葵列当种子,7 d后表现出良好的抑制发芽活性,列当种子发芽率为28.5%,与对照相比差异显著。消解动态试验表明,Tf-OR-CC消解半衰期比48%氟乐灵乳油延长6.56 d,说明Tf-OR-CC具有一定的缓释作用。田间药效试验结果表明,滴灌施用有效成分含量为75 g/667 m~2Tf-OR-CC 45 d后,向日葵列当寄生率为32.1%,寄生强度为5.3,Tf-OR-CC制剂对向日葵列当的田间防效为36.3%。该方法可为向日葵滴灌施药技术防治向日葵列当提供科学依据。     

向日葵新品种对列当的抗性鉴定

通过田间自然寄生试验,鉴定了2个向日葵新品种对列当的抗性。结果表明,向日葵新品种TP3313列当寄生率为0%,抗寄生指数为1,为免疫品种,其他病虫害发生为害较轻,产量为261.1 kg/667m~2,具有较高的推广应用价值;TP3314向日葵列当的寄生率为0.4%,寄生指数为0.99,为高抗品种。但向日葵菌核病发生较重,产量为219.6 kg/667m~2,在生产应用过程中,应注意向日葵菌核病的防控。     

不同向日葵播期、磷肥用量及除草剂对向日葵列当寄生的影响

以高感列当的食用向日葵品种"SH363"为试验材料,采用随机区组试验,研究不同播期、磷肥施用量和化学除草剂对向日葵列当寄生的影响。结果表明:随着播期推迟,列当寄生程度呈现先升高后降低的趋势,6月14日和6月21日播种,向日葵列当寄生数量明显减少,适时晚播可以减轻向日葵列当的危害;磷肥施用量为337.5 kg/hm2时,相对对照及其他处理,列当寄生数量最少;不同剂量的48%仲丁灵、48%氟乐灵和72%金都尔处理对列当寄生均具有一定的抑制作用,其中效果最好的为72%金都尔(用量为5400 m L/hm2),在减少列当寄生方面有很好的应用前景。     

我国向日葵列当生理小种的组成与分布

为明确我国向日葵列当(Orobanche cumana Wallr.)生理小种的种类与分布,通过盆栽鉴定的方法,对我国内蒙古、新疆、河北、山西、陕西、黑龙江、吉林、甘肃等8个地区62个样点的向日葵列当生理小种构成进行鉴定,鉴定结果显示,内蒙古、新疆、河北等地区的生理小种种类比较丰富,分别为7、6、5种.内蒙古以高毒力的...     

向日葵品种抗列当寄生差异性研究

向日葵列当是危害性极大的寄生性杂草,本文从列当高度、株距、寄生深度等方面对13个向日葵品种进行了抗性水平鉴定,并分析了品种间寄生指标的差异。结果表明:列当株高一般在31～60 cm,最高66.5 cm,最低5 cm;寄生数量最多在1～10 cm的范围内,最大株距为68 cm,最小为2 cm;在5～10 cm表土深处向日葵侧根上寄生数量最多,受害也最严重;9个食用向日葵品种中,2个品种免疫,1个高抗,其余为高感;4个油用向日葵品种中1个高抗,其余为易感;不同向日葵品种在寄生率、寄生程度和寄生强度等方面呈显著差异。     

阴山北麓地区向日葵列当生理小种的鉴定及种子的单株纯化

向日葵列当是一种全寄生的种子植物,对向日葵生产造成严重的影响,而选育抗列当品种是目前防控向日葵列当最为有效的防控措施。由于向日葵列当种群存在生理小种分化现象,因此明确不同地区的向日葵列当生理小种的类型以及分布对于抗列当品种的布局非常重要。本研究利用国际通用的向日葵列当生理小种鉴别寄主,对阴山北麓地区的武川县和四子王旗共计7个向日葵地块中采集的列当种子的生理小种进行了鉴定,结果表明除了呼和浩特市武川县头号村采集的向日葵列当样本为E小种外,其他6个不同地点采集到的向日葵列当样本均鉴定为G小种。为了更好地对向日葵品种抗列当水平进行准确的评价,本研究选择了已经鉴定为E、F和G三个小种类型的向日葵列当的样本进行了单株纯化以及扩繁。扩繁得到的列当的种子将用于准确评价向日葵不同的育种材料和品种对列当不同生理小种的抗性水平。     

向日葵列当在吕梁的发生危害及综合防治措施

向日葵列当是一年生草本检疫性杂草,主要寄生在向日葵根部,汲取营养,可使植株矮小、瘦弱,不能形成花盘,为害严重时可导致植株枯死。该杂草在吕梁市7—9月份发生,一般造成向日葵减产20%左右。针对向日葵列当在吕梁市发生特点,我们加强植物检疫措施,从种子源头上把关,采取以农业防治为主、化学防治为辅的综合防控措施,有效减轻了列当的危害。     

Orobanche cumana race F: performance of resistant sunflower hybrids and aggressiveness of populations of the parasitic weed

The production of sunflower is threatened by Orobanche cumana (broomrape) infections in many countries of southern and eastern Europe. The most virulent race of this parasitic weed, race F, is widespread in Spain. Most of the current commercial hybrids of resistant sunflower do not completely prevent broomrape emergence in the field. The performance (broomrape incidence and severity, final yields and oil contents) of four resistant and two susceptible sunflower hybrids was studied in different years in several O. cumana – infested locations. O. cumana – sunflower interactions were characterised by low severity and intermediate incidence in the resistant hybrids; both depended on the environment. An increase in sunflower yield because of the use of resistant hybrids was most noticeable under heavy field infestations and under drought. Characterisation of 20 populations of O. cumana classified as race F in terms of the standardised area under the degree of attack progress curve (SAUDC) and O. cumana incidence (BI) suggested differential intrinsic pathogenicities. These results highlight the variability within race F of O. cumana , mirroring the environmentally dependent horizontal resistance in sunflower.     

烟草及向日葵上列当Orobanche cumana的发生及其生物防治

 近年,在河北省部分烟草和向日葵种植地发现大量寄生性杂草列当发生并造成严重为害。经鉴定为向日葵列当Orobanche cumana Wallr.。向日葵、烟草、番茄和黄瓜等作物的根分泌物能够刺激向日葵列当O. cumana种子萌发,而油葵根的分泌物则不能刺激向日葵列当种子萌发。利用列当致病镰刀菌L2菌株进行田间生物防治,防治效果达到92.4%。L2菌株对小麦、玉米、棉花、烟草和向日葵等作物生长无影响,L2菌株粗毒素能够抑制列当种子萌发,并造成列当种子萌芽管损伤。     

Benzothiadiazole Activates Resistance in Sunflower (Helianthus annuus) to the Root-Parasitic Weed Orobanche cuman

ABSTRACT The study was conducted to evaluate the potential of induced resistance to infestation of sunflower (Helianthus annuus L.) by the parasitic weed Orobanche cumana Wallr. Treatment of sunflower seeds with 40 ppm of benzo(1,2,3)thiadiazole-7-carbothioic acid S-methyl ester (BTH) for 36 h completely prevented infection in root chambers. In pot studies using 2.86 x 10(-4) g of Orobanche seeds per gram of soil as inoculum, the total number of O. cumana shoots was reduced by 84 and 95% in the 60-ppm BTH treatment in the first and second trial, respectively. Evaluation of the disease incidences revealed that attachment of O. cumana at the sunflower root and the stage of early penetration was reduced in the BTH-treated plants. Chemical analysis of root extracts revealed synthesis of the phytoalexin scopoletin and of hydrogen peroxide in the BTH-treated sunflower roots, but no increase in lignification. Western blot analysis demonstrated accumulation of the pathogenesis-related protein chitinase in roots and stems of induced resistant plants. These results show that the phenomenon of induced resistance is not restricted to viral, bacterial, and fungal disease and demonstrate the great potential of this protection strategy as an effective component of future plant production systems.     

列当(Orobanche spp. and Phelipanche spp.)种子的采集与预处理方法

列当(Orobanche spp.and Phelipanche spp.)是一种在世界范围内危害严重的根寄生杂草,防除列当的研究也越来越多。正确地采集和预培养列当种子是获得正确防除列当研究结果的前提。列出了大田正确采集列当种子的方法,以及对采集到的种子进行过筛提纯、加洗洁精和吐温20清洗后,再表面消毒和预培养,并通过发芽试验检验此方法的可行性。结果表明,经过处理的向日葵列当、瓜列当种子的发芽率最高分别为54.4%、59.1%。此方法可以应用于列当的采集和预处理过程中,可为列当研究和防除提供参考。     

Molecular analysis of resistance mechanisms to Orobanche cumana in sunflower

Resistance to the dicotyledenous parasite Orobanche cumana in sunflower is characterized by a low number of parasitic attachments and a confinement of the parasite in host tissues leading to its necrosis. To help understand what determines such resistance mechanisms, molecular, biochemical and histological approaches were employed before (early response) and after (late response) attachment of the broomrape parasite to susceptible (2603) and resistant (LR1) sunflower genotypes. The expression patterns of 11 defence-related genes known to be involved in different metabolic pathways (phenylpropanoids, jasmonate, ethylene) and/or in resistance mechanisms against microorganisms were investigated. RT-PCR and cDNA blot experiments revealed that the resistant genotype exhibited a stronger overall defence response against O. cumana than the susceptible one, involving marker genes of the jasmonate (JA) and salicylic acid (SA) pathways. Among them, the SA-responsive gene, def. (defensin), appeared to be characteristic of LR1 sunflower resistance. However, no JA accumulation and similar SA contents (250–300 ng g⁻¹ FW) were measured by GC/MS in both genotypes, parasitized or not. In addition, three cDNAs, isolated by a suppression-subtractive hybridization, were shown to be strongly induced only in the resistant genotype 8 days post-inoculation, when the first O. cumana attachments occurred. These genes, putatively encoding a methionine synthase, a glutathione S-transferase and a quinone oxidoreductase, might be involved in detoxification of reactive oxygen species, suggesting the occurrence of an oxidative burst during the incompatible interaction. Finally, host cell-wall modifications leading to parasite-confinement were correlated with more intense callose depositions in the resistant genotype, concomitant with over-expression of the callose synthase cDNA HaGSL1 .     

Prohexadione-calcium induces sunflower (Helianthus annuus) resistance against the root parasitic weed Orobanche cumana

Prohexadione-calcium (PHDC) is a plant growth retardant that inhibits gibberellin biosynthesis and transiently alters the spectrum of flavonoids and their phenolic precursors. In this study, root chamber and pot experiments were conducted to evaluate the effects of PHDC on Orobanche cumana seed germination and induction of sunflower resistance to this root parasitic weed. Root chamber experiments indicated that PHDC did not interfere with the progress of Orobanche seed germination, but retarded O. cumana tubercle formation and development. In pot experiments, control of O. cumana by PHDC depended on its dose, method of application and sunflower cultivar. In sunflower cv. HA89, PHDC at 10 mg LS⁻¹ (litre soil) as two drenches or at 1 m m as two foliar sprays significantly reduced the total number and dry matter of O. cumana without influencing flower, leaf and root development. In sunflower cv. Albena, PHDC at 20 and 30 mg LS⁻¹, but not at 10 mg LS⁻¹, as two drenches significantly reduced O. cumana infection. Sunflower cv. HA89 was less susceptible to O. cumana and more inducible by PHDC than sunflower cv. Albena. The biochemical analysis of root extracts revealed a significantly higher accumulation of free phenolics in sunflower cv. HA89 after PHDC soil drench, but not in Albena. No significant lignification was observed after PHDC treatments. The results suggest that PHDC reduces O. cumana infection in sunflower by inducing host resistance, not by directly interfering with the parasite. Free phenolics play an important role in sunflower response to the parasite.     

苹果蠹蛾生物防治技术的研究和应用进展

苹果蠹蛾Cydia pomonella（L.）是我国重要的检疫害虫,已经在我国新疆、甘肃、宁夏、内蒙古、黑龙江和吉林6个省区发现,对我国苹果产业构成了严重威胁。目前,我国苹果蠹蛾的主要防治方法仍旧是传统的化学防治。但考虑到安全性、环境影响和化学农药持久性等问题,人们开始重视采取害虫综合治理策略（IPM）,其中生物防治占有非常重要的地位。本文综述了国内外苏云金芽胞杆菌、白僵菌、颗粒体病毒、昆虫病原线虫和寄生蜂在苹果蠹蛾防治中的研究和应用情况。同时,针对生防技术在果园农业生态系统IPM防治体系中所发挥的作用也进行了探讨,包括目前亟待解决的问题和应用前景,以期为我国苹果蠹蛾防控策略的研究和应用提供参考。