木薯对伴生杂草化感作用的初步研究

以白菜和木薯园伴生杂草(假臭草、三叶鬼针草)为受体植物,采用生物测定的方法研究了新鲜木薯叶片4种浸提液的化感作用.结果表明,4种浸提液对受体植物种子萌发率、根长和茎长的生长发育均有不同程度的抑制作用,且浓度越大抑制作用越强;其中乙酸乙酯和水浸提液的抑制作用较强,甲醇和氯仿浸提液的抑制作用相对较弱.研究表明,木薯叶浸提液中含有抑制伴生杂草(假臭草和三叶鬼针草)种子萌发和幼苗生长的化感物质,为进一步开展具有化感潜力木薯品种的研究提供了理论基础.     

圆柏果实水浸提液化感作用的初步研究

圆柏(Sabina chinensis L.)成年母树周围很少有实生苗生长,为了检测该植物组织是否具有抑制种子发芽的作用,通过测定圆柏果皮和种子水浸提液对萝卜、白菜和圆柏种子萌发及幼苗根长和苗高的影响,对圆柏果实化感物质的作用进行了研究。结果显示:在高浓度0.1 g/mL果皮水浸提液处理下,萝卜和白菜种子的萌发、苗高和根长生长均受到显著的抑制作用,随着浸提液浓度的降低,其抑制作用逐渐减弱;低浓度(0.01 g/mL,0.03 g/mL)的果皮水浸提液对萝卜种子的萌发、幼苗苗高和根长均表现为促进作用,对白菜种子萌发、幼苗苗高和根长有抑制作用;圆柏种子浸提液对萝卜、白菜种子萌发及幼苗生长的抑制作用不显著。圆柏果实水浸提液对萝卜和白菜具有明显的化感作用,化感物质主要存在于果皮中,而且圆柏果实的化感作用对参加试验的萝卜和白菜种子具有选择性。圆柏种子在该试验中未发芽,TTC法检测参加试验圆柏种子的活力,发现果皮浸提液处理的圆柏种子有34%具有生活力,子叶在转绿;种子浸提液处理的圆柏种子有37%具有生活力,子叶也在转绿,圆柏种子的发芽率比较低,很大程度上取决于种子的质量,圆柏对自身种子的发芽及幼苗生长的自毒效应需要进一步研究。     

剑麻叶不同溶剂浸提液对假臭草萌发和生长的影响

以剑麻园常见伴生杂草假臭草为受体植物,白菜和萝卜为参照受体植物,采用生物测定的方法研究剑麻新鲜叶片石油醚、乙酸乙酯、三氯甲烷、蒸馏水4种溶剂浸提液对受体植物种子萌发和生长的影响。结果表明,4种溶剂浸提液对受体植物种子萌发率、根长和茎长生长均有不同程度的影响。500mg／mL蒸馏水浸提液和三氯甲烷浸提液对假臭草种子的萌发和幼苗的根长总体上具有显著的抑制作用,抑制率分别达到29％和50％;500mg／mL蒸馏水浸提液对萝卜种子萌发和根长生长具有显著的抑制作用,抑制率分别达到45．00％和64．22％;500mg／mL乙酸乙酯浸提液对白菜种子萌发和根长生长的抑制作用较强,抑制率分别达到30．49％和56．59％。说明剑麻不同溶剂、不同浓度浸提液对不同的受体植物均存在不同程度的化感作用,这为进一步开展利用剑麻的化感物质抑制杂草的研究提供了理论基础。     

肿柄菊水浸提液对3种作物的化感作用研究

采用培养皿滤纸法测定肿柄菊不同浓度水浸提液对豌豆、萝卜和水稻种子萌发、幼苗生长的影响.结果表明:肿柄菊浸提液对豌豆和萝卜种子萌发有抑制和延缓作用,对水稻最终萌发率无显著影响;低浓度的浸提液可促进受体植物幼苗生长,高浓度则有显著的抑制作用,同时还发现高浓度浸提液可降低受体植物叶绿素、可溶性蛋白质和糖的含量.     

石刁柏4种浸提液对几种受体植物的化感作用

用白菜、假臭草和红毛草为受体植物,采用生物测定的方法研究了石刁柏新鲜茎叶4种浸提液的化感作用,结果表明：红毛草受石刁柏茎叶浸提液的抑制作用最强;4种溶剂的浸提液对假臭草萌发率的作用效果表现出“低浓度促进,高浓度抑制”的双重效应,而对其幼苗根茎生长具有明显的抑制作用,且浓度越大抑制作用越强;4种溶剂的浸提液对白菜萌发率和根长的作用在总体上也表现出显著的抑制作用,但对其茎长却有明显的促进作用。说明4种浸提液对受体植物种子萌发率、幼苗的根长和茎长均有不同程度的化感作用,这为利用石刁柏的化感作用控制杂草提供了理论基础。     

蒙山莴苣化感作用对4种草坪草种子萌发的影响

为了合理地控制草坪生长与管理草坪,初步研究蒙山莴苣[Mulgedium tataricum（L.）DC.]根、叶、茎的浸提液及5个不同浓度茎浸提液对校园内采的高羊茅（Festuca arundinacea Schreb.）、高羊茅千年盛世（Millennium）、一年生黑麦草（Lolium multiflorumL.）蓝天堂（Blue Heaven）、多年生黑麦草（L.perenneL.）球道（Fairway）4种草坪草的化感作用,通过对受体种子发芽率、幼苗长度、根长以及幼苗中过氧化氢酶活性、可溶性蛋白含量等指标的测定发现：蒙山莴苣浸提液对草坪草的种子萌发以及幼苗的生长均表现出抑制作用,其强度为茎〉叶〉根。总体上随着茎浸提液浓度的增大,草坪草受抑制作用有所增强。蒙山莴苣浸提液对幼苗中CAT活性影响各异,且抑制幼苗中可溶性蛋白合成,其中茎浸提液抑制作用最大。     

小麦及变异后代对部分农田杂草的化感效应及其防控潜力

以外源DNA供体高粱、变异新品系89122和春小麦品种陇春13号为试验受体,3种杂草水浸提液为试验供体,通过正向和逆向化感抑制敏感性测试与评价,分析3种作物的遗传变异特性和化感潜力,评估小麦化感抑草潜力变异特性及遗传机制,为实现小麦抗杂草潜力的遗传改良提供理论支撑。结果表明,高粱DNA导入受体春小麦陇春13号后,其后代在农艺性状等方面发生变异,其对供试杂草的化感敏感性也发生变异;3种杂草水浸提液对3种供试作物种子萌发、幼苗形态特征和物种水平均有不同程度的抑制作用,且抑制作用随处理浓度的增大而增强,具有明显的浓度依赖性;灰绿藜除在种子萌发阶段对高粱的化感抑制作用较弱外,在其他作物幼苗生长阶段的化感抑制作用均明显强于稗和狗尾草,印证了灰绿藜在农田杂草群落中较强适应性主要表现在其对作物幼苗生长阶段的影响,而非种子萌发阶段。灰绿藜通过化感抑制作用实现自身竞争力提升,成为本区域的优势杂草,进一步拓宽了其生态位宽度,它在农田生态群落中的多维影响力强于稗和狗尾草。供试作物种子萌发阶段的敏感性要大于幼苗生长阶段,表现在其发芽指数的敏感性要大于萌发率,说明供试农田杂草通过降低种子发芽指数、延长发芽时间来...     

银胶菊植株水浸提液对几种植物的化感作用

以萝卜、黄瓜、三叶鬼针草和马唐4种植物的种子为供试对象,测定了银胶菊植株水浸提液的化感活性.结果表明:(1)低浓度(0.01 g/ml)的银胶菊植株水浸提液对萝卜和黄瓜种子的萌发没有影响,相对萌发率均为100%,而对萝卜和黄瓜幼苗的生长却表现为促进作用,相对苗长分别为174.3%和103.9%,相对根长分别为151.9%和103.9%;(2)高浓度(0.5 g/ml)的银胶菊植株水浸提液对萝卜和黄瓜的种子萌发率、幼苗根长和苗高均表现为抑制作用,并随着浓度的提高,抑制作用增强;(3)不同浓度的银胶菊植株水浸提液对三叶鬼针草和马唐的种子萌发率、幼苗根长和苗高均表现为抑制作用,并随着浓度的提高,抑制作用增强.其中,当水浸提液浓度为0.5 g/ml时,三叶鬼针草和马唐的种子相对萌发率为0,受到强烈的化感作用.     

黄花刺茄浸提液对番茄种子萌发及幼苗生长的影响

为明确入侵植物黄花刺茄对当地主栽经济作物番茄种子萌发和幼苗生长的影响,本文采用培养皿滤纸法,在智能光照培养箱的变温控制条件下,分别研究了黄花刺茄根、茎、叶浸提液对番茄种子发芽率、发芽指数及幼苗根长和苗高的影响。结果表明:(1)黄花刺茄不同器官的浸提液对番茄种子发芽率、发芽指数、幼苗根长和苗高的影响不同,其茎、叶浸提液的化感作用较为显著(P<0.01)。(2)黄花刺茄同部位浸提液对番茄种子发芽率、发芽指数、幼苗根长和苗高不同指标的影响也不同。根浸提液对种子发芽率、幼苗根长影响不显著(P>0.05),但对种子发芽指数的影响极显著(P<0.01)。茎和叶浸提液各浓度对种子发芽指数的影响比种子发芽率、幼苗根长和苗高的影响显著(P<0.01)。     

油菜对千金子的化感作用及其化感物质分离鉴定

研究了油菜茎根水提液对后茬稻田中恶性杂草千金子的化感作用,并分离鉴定了化感物质。结果表明,不同品种油菜的水提液对千金子种子萌发有抑制作用,对幼苗生长无影响,同时对水稻种子萌发及幼苗生长安全。利用室内生测及GC-MS方法鉴定抑制千金子种子萌发的化感物质为有机酸,抑制率达100%。其主要成分为油酸、棕榈酸、芥酸、亚油酸、硬脂酸、二十碳烯酸及山嵛酸。     

Dermestid beetles in ‘evolution Canyon’, lower Nahal Oren, Mt. Carmel, including new records for Israel

Fifteen species of dermestid beetles were recorded at ‘Evolution Canyon’ (EC), Lower Nahal Oren, Mt. Carmel, Israel. They represent ~35% of known Israeli dermestid species. The following three species were recorded for the first time in Israel:Trogoderma svriaca Dalla Torre, 1911;Ctesias svriaca Ganglbauer, 1904; andAnthrenus (s.str.) jordaniens Pic, 1934. Adults of 13 species were collected on the more solar radiated, warmer and climatically more fluctuating south-facing slope (SFS); ten species were collected on the opposite, north-facing slope (NFS), which was cooler and climatically more stable. The abundance of adult dermestid beetles was 1.9 times higher on the SFS than on the NFS (86 and 47, respectively). Species richness and abundance distribution at EC (three collecting stations on each slope and one at the valley bottom) were significantly negatively correlated with the plant cover that consisted of trees and bushes (Spearmanr _s ,P=0.007 and 0.039, respectively) and perennials (Spearmanr _s ,P=0.039 and 0.077, respectively), indicating that non-woody plants were preferred by adult dermestid beetles.     

Epidemiology of Toxigenic Fungi and their Associated Mycotoxins for Some Mediterranean Crops

Recent data on the epidemiology of the common mycotoxigenic species of Fusarium, Alternaria, Aspergillus and Penicillium in infected or colonized plants, and in stored or processed plant products from the Mediterranean area are reviewed. Emphasis is placed on the toxigenicity of the causal fungal species and the natural occurrence of well known mycotoxins (aflatoxins, ochratoxins, fumonisins, trichothecenes, zearalenone, patulin, Alternaria-toxins and moniliformin), as well as some more recently described compounds (fusaproliferin, beauvericin) whose toxigenic potential is not yet well understood. Several Fusarium species reported from throughout the Mediterranean area are responsible of the formation of mycotoxins in infected plants and in plant products, including: Fusarium graminearum, F. culmorum, F. cerealis, F. avenaceum, F. sporotrichioides and F. poae, which produce deoxynivalenol, nivalenol, fusarenone, zearalenone, moniliformin, and T-2 toxin derivatives in wheat and other small grains affected by head blight or scab, and in maize affected by red ear rot. Moreover, strains of F. verticillioides, F. proliferatum, and F. subglutinans, that form fumonisins, beauvericin, fusaproliferin, and moniliformin, are commonly associated with maize affected by ear rot. Fumonisins, were also associated with Fusarium crown and root rot of asparagus and Fusarium endosepsis of figs, caused primarily by F. proliferatum. Toxigenic A. alternata strains and associated tenuazonic acid and alternariols were commonly found in black mould of tomato, black rot of olive and citrus, black point of small cereals, and black mould of several vegetables. Toxigenic strains of A. carbonarius and ochratoxin A were often found associated with black rot of grapes, whereas toxigenic strains of A. flavus and/or P. verrucosum, forming aflatoxins and ochratoxin A, respectively, were found in moulded plant products from small cereals, peanuts, figs, pea, oilseed rape, sunflower seeds, sesame seeds, pistachios, and almonds. Finally, toxigenic strains of P. expansum and patulin were frequently found in apple, pear and other fresh fruits affected by blue mould rot, as well as in derived juices and jams.     

Broad bean mottle virus in Morocco; curculionid vectors,and natural occurrence in food legumes other than faba bean (Vicia faba)

Broad bean mottle virus (BBMV) was transmitted from infected to healthy faba-bean plants by the curculionid weevilsApion radiolus Kirby,Hypera variabilis Herbst,Pachytychius strumarius Gyll,Smicronyx cyaneus Gyll, andSitona lineatus L. The latter appeared to be an efficient vector: acquisition and inoculation occurred at the first bite, the rate of transmission was c. 41%, and virus retention lasted for at least seven days.S. lineatus transmitted the virus from faba bean to lentil and pea, but not to the three genotypes of chickpea tested. This is the first report on the generaHypera, Pachytychius, andSmicronyx as virus vectors, and onA. radiolus, H. variabilis, P. strumarius, andS. cyaneus as vectors of BBMV.Out of 351 samples of food legumes with symptoms suggestive of virus infection, 16, 11, 19, and 17% of the samples of chickpea, lentil, pea, and common bean, respectively, were found infected when tested for BBMV in DAS-ELISA. This is the first report on the natural occurrence of BBMV in chickpea, lentil, pea, and common bean. The virus should be regarded as a food-legume virus rather than a faba-bean virus solely, and is considered an actual threat to food legume improvement programmes.     

Characterization of potato potyvirus Y (PVY) isolates from seed potato batches. Situation of the NTN, Wilga and Z isolates

A collection of 38 PVY isolates from seed potato batches, originating from several Western European countries, was characterized by using current biological, serological and molecular tools differentiating PVY strains and groups. The correlation between the three kinds of tests was good but not absolute. No single serological or PCR method was able to discriminate among the five isolate groups found. Twenty-nine isolates belonged to the PVY^N strain and six to the PVY^O strain. No PVY^C was found. Two other isolates reacted serologically like PVY^O, but were unable to elicit a hypersensitive response from the Ny_tbr gene and probably represent the PVY^Z group. At the molecular level, these two isolates showed a combination of both PVY^O and PVY^N and could be recombinants of these strains. Another isolate reacted serologically like PVY^O, but induced vein necrosis in tobacco, like PVY^N-Wilga. Some PVY^N isolates caused tuber ring necrosis in glasshouse conditions. These might belong to the PVY^NTN group. The PVY^NTN, PVY^N-Wilga and PVY^Z groups probably represent pathotypes within strains PVY^N and PVY^O, respectively. The present study also confirms previous reports showing a high genetic variation at the 5 end within the PVYN strain.     

The autumn leafroller: Phenology,damage and parasitoids in a Dutch apple orchard

The phenology of the autumn leafroller,Syndemis musculana, a local pest of apple, was studied in order to forecast larval emergence. From 1983–1986, peak flight as determined with sexpheromone traps was always between 13–18 May. The duration of embryonic development was determined at various constant temperatures and used to estimate the periods of egg hatch in these four years. Each year, most eggs should have hatched in the second decade of June.Differences in attack rates between apple cultivars seem to be explained largely by the variation in picking time. Larvae are only half grown at the beginning of harvest (cv. James Grieve), and have gone into hibernation when the latest variety (cv. Golden Delicious) is picked. Moreover, the varieties Cox's Orange Pippin and Belle de Boskoop, picked about half time, are liable to receive additional damage by caterpillars brought with the picked fruits into storage.Various hymenopterous parasites were reared from caterpillars. As the only leafroller in the orchard which hibernates as mature larva,S. musculana may promote winter survival of some parasitoids, like the eulophidColpyclypeus florus.Samenvatting De fenologie van de herfstbladroller (Syndemis musculana Hübner), een incidentele plaag op appel, werd nader bepaald met het doel het uitkomen van de eieren te kunnen voorspellen. In 1983–1986 viel de piekvlucht, bepaald met behulp van feromoonvallen, steeds tussen 13 en 18 mei.De ontwikkelingsduur van de eieren bij verschillende constante temperaturen werd gebruikt om de periode van uitkomen te schatten. De meeste eieren zullen ieder jaar in de eerste helft van juni uitkomen.Geconstateerde verschillen in schade tussen appelrassen blijken goeddeels terug te voeren op verschillen in pluktijdstip. De rupsen van de herfstbladroller zijn pas half-was als de eerste appels eind augustus geplukt worden, terwijl tegen het einde van de oogst begin oktober de meeste al in winterslaap zijn. Met name tussentijdse rassen, als Cox's Orange Pippin and Schone van Boskoop, lopen extra schade op doordat grotere rupsen met de geplukte vruchten in de kist terecht komen.Uit de rupsen werden negen, al van andere boomgaardbladrollers bekende, sluipwespen gekweekt, Omdat deze bladrollersoort, als enige in de boomgaard, als volgroeide rups overwintert, lijkt zij bij uitstek geschikt als winterwaard.This study was carried out at the Experimental Orchard De Schuilenburg, Schuilenburg 3, 4041 BK Kesteren, the Netherlands, to which address correspondence should be addressed.     

Characterization of Sclerotinia minor populations in Texas peanut fields

In the summer of 2004 an epidemic of sclerotinia blight of peanut, a disease caused by Sclerotinia minor, occurred in Texas in fields where the disease was never previously detected. The disease was observed on many plants within one of the fields (>3000 disease foci), although most foci were <1 m. It is hypothesized that these observations were inconsistent with the recent introduction of a monocyclic pathogen, even if disease developed under conducive environmental conditions. The pattern of disease is most suggestive of the presence of foliar (ascospore) infections, although air temperature was above the known limits for apothecia development if the pathogen had arrived in the field in 2004 peanut seed. To further examine this epidemic, 232 isolates were collected, across a variety of spatial scales spanning this field and other Texas peanut fields, and evaluated for aggressiveness, fungicide sensitivity and genotypic diversity. There was wide variation among isolates for the phenotypic characteristics measured, but there was no evidence that a genotypically unique, highly aggressive, and fungicide resistant isolate had been introduced or evolved. The predominant genotype, TX1, which contained 154 isolates, was found in every county and field population.     

Eyespot of Cereals Revisited: ITS phylogeny Reveals New Species Relationships

Four species so far classified in Pseudocercosporella or Ramulispora (hyphomycetes) are associated with eyespot disease symptoms of cereals. Two of these have been linked to teleomorphs that were described in Tapesia. Sequence data derived from the Internal Transcribed Spacer region (ITS1, 5.8S and ITS2) of the rDNA operon showed, however, that the eyespot fungi associated with Tapesia are not congeneric with Ramulispora sorghi, the type of Ramulispora. The genus name Tapesia is now rejected in favour of the conserved name Mollisia, which appears to comprise heterogeneous fungi. Tapesia yallundae is not closely related to the type of Mollisia, M. cinerea, but clusters separately, being more closely allied to species with Cadophora anamorphs. A new holomorph genus, Oculimacula, is therefore proposed for teleomorphs of the eyespot fungi, while the anamorphs are accommodated in Helgardia gen. nov.     

Transgene herbizidresistente Kulturen

Zusammenfassung Herbizidresistente Kulturpflanzen nehmen unter den derzeit weltweit angebauten gentechnisch veränderten Ackerbaukulturen Sojabohne, Baumwolle, Raps und Mais den weit überwiegenden Anteil ein. Als Ursachen für die rasche Zunahme der Anbauflächen herbizidresistenter Sorten sind unter anderem die Unzulänglichkeiten der für diese Kulturen bestehenden Herbizidlösungen sowie die Zunahme der pfluglosen Bestellverfahren zu sehen. Im Gegenzug hat die Minimalbodenbearbeitung aufgrund der Einführung der Herbizidresistenztechnologie, insbesondere in Sojabohne, ein ausgeprägtes Flächenwachstum erfahren.Als Entscheidungskriterien für die Wahl des Unkrautbekämpfungssystems unter Einbezug des Anbaus herbizidresistenter oder konventioneller Sorten lassen sich aus den Erfahrungen der vergangenen 8 Jahre anführen: Sortenleistung, erhöhte Kulturverträglichkeit und zeitliche Anwendungsflexibilität, Wirkungssicherheit einer Nachauflaufbehandlung in Trockenregionen, Wirkungsbreite, Wirkungsdauer und Bekämpfung resistenter Unkrautbiotypen. Aufgrund fehlender Zulassungen und Kennzeichnungsvorschriften in wichtigen Exportmärkten sind für den Anbau transgener Sorten in Übersee auch Vermarktungseinschränkungen sowie für den Anbau in Europa Haftungs- und Koexistenzregeln wichtige einzelbetriebliche Entscheidungsparameter.Fortschritte erfährt die Herbizidresistenztechnologie kurz- und mittelfristig in der Weiterentwicklung bereits praktizierter Spritzfolgen und Tankmischungen zu Fertigformulierungen der Komplementärherbizide mit residualen Partnern. Zur Bekämpfung und Vorbeugung der Ausbreitung neuer herbizidresistenter Biotypen werden die Komplementärherbizide mit Partnern anderer Wirkungsmechanismen kombiniert. Weitere Entwicklungen sind die Kombination verschiedener transgener Merkmale mit der Herbizidresistenz sowie die Ausweitung von den derzeit dominierenden Kulturen auf weltweit weniger bedeutsame Kulturen, in denen die Entwicklung neuer konventioneller Herbizidwirkstoffe bisher wenig erfolgreich war oder im Verhältnis zum Aufwand nur bedingt attraktiv ist. Für die langfristige Entwicklung könnte die Plastidentransformation zur Verhinderung einer unerwünschten Ausbreitung transgener Merkmale Bedeutung erlangen.     

Pathogenic fungi involved in root rot of peas in the Netherlands and their physiological specialization

Research on root rot pathogens of peas in the Netherlands has confirmed the prevalence ofFusarium solani, F. oxysporum, Pythium spp.,Mycosphaerella pinodes andPhoma medicaginis var.pinodella. Aphanomyces euteiches andThielaviopsis basicola were identified for the first time as pea pathogens in the Netherlands. Other pathogens such asRhizoctonia solani andCylindrocarpon destructans were also found on diseased parts of roots. F. solani existed in different degrees of pathogenicity, and was sometimes highly specific to pea, dwarf bean of field bean, depending on the cropping history of the field.A. euteiches was specific to peas, whereasT. basicola showed some degree of physiological specialization.     

Surveys of cereal diseases and pests in the Netherlands. 3. Monographella nivalis and Fusarium spp. in winter wheat fields and seed lots

Data from surveys of winter wheat fields in the period 1974–1986 and of seed lots in the period 1962–1986 and identifications of diseases on plant samples were compiled to describe the occurrence of snow mould (Monographella nivalis) andFusarium spp. On average,M. nivalis dominated overFusarium spp. The complex ofFusarium spp. constituted mainly ofF. culmorum, followed byF. avenaceum andF. graminearum. M. nivalis was dominant in May on stem-bases and in July on leaves and leaf sheaths. On seedsM. nivalis predominated only in years with low temperatures in July and August.Average brown footrot infection in the field was 4% tillers in May and 5% culms in July. Brown footrot intensity in July was high in cropping seasons with high precipitation in October and with low temperatures in October, November and December. In July during the early eighties, an average of 8% of leaves and 6% of flag leaf sheaths were infected byM. nivalis. Average ear blight incidence was 1.2% glumes infected. Seed contamination by these pathogens averaged 16% in the years 1962–1986. The contamination was high in years with high precipitation in June, July and August. Aspects of cv. resistance and yield loss are illustrated.