细胞色素P450抑制剂对白腐菌Phlebia lindtneri降解氯丹的影响

为确定细胞色素P450酶系在白腐菌Phlebia lindtneri降解有机氯类农药氯丹中的作用,在液体培养条件下,以胡椒基丁醚和1-氨基苯并三唑作为细胞色素P450的抑制剂,分析了不同浓度抑制剂对氯丹的降解、代谢产物的生成以及中间代谢物降解的影响。结果表明:与对照相比,高浓度(1.0 mmol/L)胡椒基丁醚或1-氨基苯并三唑处理15 d后氯丹的降解率均下降了约60%,且其代谢产物中除七氯和二氯代六氯的检出量显著增加外,其余环氧化及羟基化代谢产物均未检出;此外,添加高浓度的抑制剂可导致白腐菌降解中间代谢产物七氯及二氯代六氯的降解率下降90%以上,氧化氯丹的降解率下降70%以上,但不影响环氧七氯的降解。表明细胞色素P450可能是氯丹降解的主要酶系,其参与催化了氯丹的初始羟基化和水解、七氯和二氯代六氯的环氧化及氧化氯丹的水解等多个反应过程。     

雷竹内生真菌分离及其功能性菌株筛选与鉴定

[目的]从雷竹根部分离其内生真菌并对其纤维素降解、植物病原菌抑制、铅的耐受能力等功能进行初步探究.[方法]采用组织块培养法分离内生真菌,刚果红平板培养基筛选纤维素降解菌,平板对峙法筛选植物病原拮抗菌.[结果]从雷竹根部共分离到35株内生真菌,其中具有纤维素降解功能的有7株;对油茶炭疽病原有抑制作用的有5株,对毛竹枯梢病原有抑制作用的有2株,对猕猴桃果腐病原有抑制作用的有2株;对铅具有强耐受性的有11株.利用形态特征和分子生物学方法对两株具有良好潜在应用价值的内生真菌LZ031、LZ033进行鉴定,分别为腐皮镰刀菌(Fusarium solani)和芦竹节菱孢(Arthrinium arundinis).[结论]雷竹根部具有丰富的内生真菌资源,且内生真菌功能多样,具有潜在的应用价值.     

难降解农药的登记管理及其风险分析

近年来在环境中难降解农药对生态环境的影响在登记管理中引起关注。本文介绍了欧盟、美国等国家对难降解农药的登记管理现状,讨论了农药的降解性与农药在环境中的浓度的关系,并提出了对难降解农药的管理建议。欧盟对同时具有难降解、高富集性的农药设置了阈值,但未对难降解农药划定不准许登记的阈值,而是通过环境风险评估确定农药的风险;美国、日本、澳大利亚等国家未对难降解农药登记设置阈值。多元线性回归表明,农药的降解DT50对土壤中农药浓度的影响显著,但并不是影响土壤中农药浓度的最主要因素。建议我国登记管理中也不宜对难降解农药划定不准许登记的阈值;对于符合持久性有机污染物定义的农药应履行《斯德哥尔摩公约》,对其他农药,应根据已发布的农药环境风险评估标准开展环境风险评估。     

浅谈有机杀虫剂的微生物降解

寻找,研究有机杀虫剂及其残留物的降解菌有益于环境保护,综述ＤＤＴ等９种有机杀虫剂的降解微生物,其微生物降解农药的途径,及其应用现状和前景。     

聚酰胺和聚甲基丙烯酸甲酯微塑料对异菌脲土壤环境行为的影响

微塑料可以吸附环境中的有机污染物,可能会影响农药在土壤中的降解、吸附和迁移等环境行为,其影响与微塑料和农药的类型有关.为明确微塑料对异菌脲在土壤中环境行为的影响,通过室内模拟试验,研究了聚酰胺(PA)和聚甲基丙烯酸甲酯(PMMA)微塑料对异菌脲在土壤中吸附、迁移、淋溶和降解的影响.研究结果表明:含2％(质量分数,下同)...     

两种新农药主要特性及使用方法

两种新农药主要特性及使用方法消菌灵：是南京农业大学实验农药厂研制生产的杀菌剂，剂型为５０％消菌灵水溶性粉剂。其主要特性：对细菌、真菌、病毒均有较强的杀灭作用；防治对象广谱，对稻白叶枯病、稻细菌性条斑病、稻瘟病及经济作物、蔬菜、果树等的病毒病、腐烂病有...     

降解残留有机农药的微生物资源研究进展

有机农药污染已成为一个世界性问题,微生物在环境农药残留修复中起着重要作用。对降解有机磷、有机氯、拟除虫菊酯类和有机氮等农药的微生物种属资源以及相关酶资源和基因资源的研究进展进行了综述,分析了近年来该领域中对微生物资源的开发和利用状况,并讨论了在环境修复、生物防治和生物肥料等方面多功能化应用微生物资源,同时保障转基因生物安全,避免对环境造成二次污染等应成为该领域重要的研究方向。     

真菌农药标准制定中若干问题的探讨

本文对当前真菌农药的研究、应用和管理进行了综述和分析,在此基础上提出了真菌农药标准制定中存在的问题,指出了制定真菌农药标准应遵循的原则和依据,并探讨了解决这些问题的方法和建议.     

微生物降解农药的研究进展

在农药的微生物降解研究中,分离构建一种由天然微生物构成的复合系,将其应用于被污染的环境是消除农药污染的一个有效方法。本文综述了环境中降解农药的微生物种类、微生物降解农药的机理、在自然条件下影响微生物降解农药的因素及农药微生物降解研究方面的新技术和新方法。     

莠去津微生物降解的研究进展

综述了莠去津降解微生物的筛选方法、降解速度的影响因素、降解机理,并对农药降解微生物的应用前景进行了展望。对降解农药微生物的研究不但可以得到消除莠去津环境污染的菌株和相应的酶制剂,而且对于抗莠去津转基因技术的研究也有促进作用。     

Degradation of insecticide lindane (γ‐HCH) by white‐rot fungi Cyathus bulleri and Phanerochaete sordida

An Erratum for this article has been published in Pest Management Science 56(5) 493 (2000). The degradation of the insecticide lindane (γ‐hexachlorocyclohexane, γ‐HCH) by two white‐rot fungi, Cyathus bulleri and Phanerochaete sordida, was studied. C bulleri degraded lindane more efficiently than P sordida. Two degradative intermediates identified in P sordida culture were tetrachlorocyclohexene and tetrachlorocyclohexanol. However, tetrachlorocyclohexanol was the sole degradation product detected in cultures of C bulleri. The presence of lindane only inside the mycelial cells of both fungi eliminated any role of intracellular enzymes during initial steps of its degradation. The insecticide at 0.27 µM showed no adverse effect on fungal growth. © 2000 Society of Chemical Industry     

Population dynamics of epiphytic mycoflora and occurrence of bunch rots of wine grapes as influenced by leaf removal

Population dynamics of epiphytic fungi associated with the summer bunch rot complex of five wine grape ( Vitis vinifera ) varieties in commercial vineyards in the San Joaquin Valley of California were monitored every two weeks by berry washings during 1989-1992. Vines in the five replicated experiments were subjected to basal leaf removal or left unaltered. Although numerous genera of fungi were isolated, species of Cladosporium, Aspergillus, Penicillium and Alternaria predominated. Population densities of most fungal taxa increased at or after véraison. Leaf removal in the fruiting zones of bilateral cordon-trained vines generally reduced ( P >0·05) mid to late season numbers of epiphytic mycoflora: species of Penicillium, Botrytis and Aspergillus were most commonly reduced. Populations of Alternaria spp. and yeasts were not consistently affected by leaf removal. Numbers of fungi were no lower on berries when leaves were removed from both sides of vines than when leaves were removed only from the shaded side. Incidence and severity of bunch rots (sour rot, rots caused by Botrytis cinerea, Aspergillus niger , and total rot) at harvest were consistently reduced where leaves had been removed in comparison to vines where no leaves were removed. In one experiment, berries from vines sprayed with the grower's choice of pesticides at 50% or 100% of label rates had similar numbers of epiphytic mycoflora in both cases frequently lower than those from unsprayed controls. There was a significant interaction between chemical rate and leaf removal on the incidence of sour rot at harvest. Timing and extent of leaf removal did not affect population dynamics of epiphytic fungi, or incidence or severity of bunch rots ( P ≤0·05) at harvest in other trials.     

Evaluation of fungal antagonists for control of onion white rot in soil box trials

Four fungi ( Chaetomium globosum, Trichoderma viride, T. harzianum, Trichoderma sp.) were capable of reducing the incidence of onion white rot relative to the untreated control in two soil-box trials. When applied as a soil additive (sand: bran: fungal homogenate, 1:1:2) at the rate of 0-1% wheat bran/g dry soil, all fungal isolates provided levels of disease control equivalent to the fungicide (procymidone 0-5 g a.i./100g seed) treatment. The best results were achieved with the Chaetomium globosum and Trichoderma (C62) isolates which gave 78% and 73% control of white rot. respectively, in trial 1 and 67% and 73% control, respectively, in trial 2. Reduced control was observed when the test fungi were applied as seed coatings or incorporated into alginate pellets.     

天麻芽腐病致病菌鉴定及发生危害调查

在天麻种子园或温室内,掩埋在沙床中作为育种材料的部分箭麻及其花茎表现为芽腐、首腐、勾头、茎基腐等症状,常导致约25%的箭麻不能开花结实。病原真菌在PDA加富培养基上或发病部位,形成白色至淡紫色菌落及粉红色的分生孢子堆,分生孢子大小两型;后产生厚垣孢子,经鉴定为尖镰孢(Fusarium oxysporum Schl.)。箭麻及土壤带菌是主要传染源,伤口是主要侵染途径。     

The degradation of residual pesticides and the quality of white clover silage are related to the types and initial concentrations of pesticides

In order to understand the degradation of different residual pesticides of white clover silage and their influence on silage quality, three commonly used orchard pesticides with different concentrations were added to the white clover and fermented for 90 days. The results showed that the degradation rate of cypermethrin and its toxic degradation product 3-phenoxybenzoic acid (3-PBA) was the highest after silage, at different concentrations, both were 100%. The degradation rate of Tebuconazole and chloropyridine was 72.47–80.27% and 47.76–64.82%, of which 3,5,6-trichloro-2-pyridinol (TCP) content, poisonous toxic degradation product, increased 0.0525–0.253 mg·kg⁻¹. The residues of beta-cypermethrin and tebuconazole had reached safety standards after silage. As compared with the control, the contents of lactic acid, acetic acid, and propionic acid increased in the treated samples. The higher concentrations of three pesticides all significantly reduced the lactic acid content of silage (p<0.05). Pesticides had different effects on the nutritional components of white clover silage. Conclusively, silage is a potential way to expand the utilization of covering plants in orchards.     

不同轮作模式对花生病虫害及产量的影响

为探明水旱轮作模式对花生土传病虫害及其产量的影响,设水旱轮作不施药、水旱轮作减施药、旱旱轮作常规施药和旱旱轮作不施药(CK)4种处理,于2014—2016年对花生果腐病、白绢病和蛴螬虫害的发生情况进行调查,并对花生产量及其构成因素进行考种分析。结果表明,水旱轮作不施药处理的花生果腐病病情指数和发病率分别较CK显著降低90.40%和96.55%,防控效果达96.34%;水旱轮作减施药处理对花生果腐病的防控效果为81.49%;旱旱轮作常规施药处理对花生果腐病无防控效果。水旱轮作和旱旱轮作常规施药处理对白绢病均无防控效果。水旱轮作不施药、水旱轮作减施药和旱旱轮作常规施药处理对蛴螬的防控效果分别为63.80%、65.50%和66.20%。水旱轮作不施药与旱旱轮作常规施药处理相比,株结果数、株果重和产量分别显著降低15.03%、12.14%和6.33%,株饱果数和出仁率分别显著提高13.88%和3.01%,株根瘤个数显著提高166.22%;水旱轮作减施药与旱旱轮作常规施药处理相比,株结果数、株果重、产量、百仁重和出仁率均无显著差异,株饱果数显著提高14.33%,株根瘤个数显著提高122.97%。表明水旱轮作模式对花生果腐病和蛴螬有较理想的防控效果,且使花生产量结构明显优化,根瘤菌数量显著提高。     

Causes of incipient rot and rot in regrowth Eucalyptus diversicolor (karri) trees

Eucalyptus diversicolor (karri) is the second most important commercial timber tree in Western Australia. Sawlogs from regrowth trees often have a discoloration in the heartwood that is more abundant than in sawlogs from mature trees. Other symptoms in regrowth logs include white rot, white pocket rot and brown rot. Fungal isolations and pathogenicity tests were conducted to determine whether this discoloration was incipient rot, and if so, what caused it and which rot(s) would eventually develop. A combined sample of 329 discs from recently felled trees and freshly cut scantling had discoloration in 48%, white rot in 14%, white pocket rot in 12% and brown rot in 4% of pieces of wood. Hymenochaete semistupposa was isolated from 22% of discoloured wood and 39% of white pocket rot samples. Stereum hirsutum was isolated from 4% of discoloured wood and 13% of white rot samples. Koch's postulates in regrowth karri trees showed that H. semistupposa caused extensive discoloration, with white pocket rot developing in the heartwood within 4 years, while S. hirsutum caused extensive discoloration, with white rot developing in both the heartwood and sapwood within 2 years. It was concluded that the discoloration was incipient rot, which would eventually develop into either white rot or white pocket rot.     

Effects of root- and stolon-infecting fungi on root-colonizing nematodes of white clover

The effects on white clover ( Trifolium repens ) of different combinations of the nematodes Meloidogyne trifoliophila , Helicotylenchus dihystera and Heterodera trifolii and nine stolon-infecting and three root-infecting fungi were studied in a glasshouse experiment. The presence of the fungus Phytophthora megasperma alone increased ( P  < 0·001) root-rot severity and reduced ( P  < 0·001) plant growth. Other species combinations, such as Phoma nebulosa and Alternaria alternata , interacted and increased root-rot severity. Combinations of P. megasperma with Pythium irregulare , and P. nebulosa with Phoma medicaginis or A. alternata , increased M. trifoliophila populations. Several other fungi ( P. irregulare , P. nebulosa , Colletotrichum coccodes , Macrophomina phaseolina , P. medicaginis and Phoma sp.) interacted with the nematode M. trifoliophila causing severe root-knot symptoms. The results indicated that fungi and nematodes interacted to cause root and stolon rot and reduced yields, and that poor persistence of white clover in pastures is likely to be a problem with a complex etiology.     

桃褐腐病菌抗药性分子机理研究进展

桃褐腐病是严重危害桃生产的重要病害之一。在实际生产中,该病害的控制主要以化学防治为主。由于杀菌剂的大量使用,桃褐腐病菌已对几类常用的杀菌剂产生了不同程度的抗药性。本文就桃褐腐病菌(Moniliniaspp.)对生产上使用的几大类杀菌剂的抗药性情况及抗药性分子机制研究进展进行简单概述和分析,以供国内同行借鉴与参考。     

乳茄3种新病害病原菌鉴定

 乳茄(Solanum mammosum),又叫多头乳茄、五指茄、五代同堂、黄金果,为茄科茄属常绿小灌木。乳茄是一种珍贵的观果植物,原产美洲,近年引入我国广东、广西及云南种植,因其果色鲜艳,且观果期长,果形奇特,有“五子拜寿”和“五子登科”的寓意,在切花和盆栽花卉上广泛应用。