主要环境及营养因素对西瓜枯萎病菌生长的影响

采用菌丝生长速率法和产孢量测定研究了不同温度、光照、pH及碳氮源对来源于海南、河北和上海的3株西瓜枯萎病菌Fo-HN-46、Fo-HB-12和Fo-SH-1生长速率和产孢量的影响。结果表明:西瓜枯萎病菌菌株的适宜生长温度为20~30℃,Fo-HN-46最适生长温度为28℃,Fo-HB-12和Fo-SH-1最适生长温度为25℃,产孢的最适温度为28~30℃;光照对西瓜枯萎病菌生长速率无显著影响,对产孢影响显著,Fo-HN-46在黑暗条件下单位面积产孢量最高,Fo-HB-12和Fo-SH-1在半光照条件下产孢量最高;pH对西瓜枯萎病菌菌株的生长速率和产孢量有显著影响,pH 7~9时菌丝生长速率快,pH 8~11时产孢量高;葡萄糖、淀粉和乳糖作为碳源能够显著增加西瓜枯萎病菌的产孢量;蛋白胨作为氮源能显著促进菌丝生长,硝酸钠、酵母粉和蛋白胨均能显著增加西瓜枯萎病菌的产孢量。用最适碳源、氮源培养,Fo-HN-46生长速率大于Fo-HB-12和Fo-SH-1。Fo-SH-1产孢量高于Fo-HN-46和Fo-HB-12。     

黄瓜枯萎病拮抗菌的拮抗促生因子检测及生物效应研究

以黄瓜枯萎病病原菌,尖孢镰刀菌黄瓜专化型(FOC,Fusarium oxysporum f.sp.cucumerinum)为靶标筛选拮抗菌。通过初筛和复筛,获得2株对尖孢镰刀菌黄瓜专化型拮抗效果稳定、拮抗能力较强的细菌QHZ-Yb1和QHZ-Yb2(以下简称,Yb1和Yb2),采用平板对峙法测定其拮抗作用,抑菌带宽度达3.37 mm和3.42 mm,抑菌圈直径2.7 cm,抑菌率分别达到61.9%和62.3%;通过形态学结合生理生化及菌株的16S rDNA序列分析,初步确定这两株菌均为萎缩芽孢杆菌(Bacillus atrophaeus);潜在拮抗促生因子的测定结果表明:菌株Yb1和Yb2具有多种拮抗促生因子,其脂肽类粗提取物的抑菌率分别达到57.4%和58.0%,生长素IAA的分泌量可达1.56 mg·L~(-1)和3.69 mg·L~(-1),溶P量为0.77 mg·L~(-1)和1.19 mg·L~(-1),两个菌株均可产嗜铁素、分泌酪蛋白酶;种子萌发试验结果表明:Yb1和Yb2菌液均可促进黄瓜种子的萌发;菌株生物效应的盆栽试验结果表明:Yb1、Yb2以及Yb1+Yb2菌悬液的处理不仅对黄瓜枯萎病有明显的生防效果,而且可显著增加黄瓜植株的生物量,增加黄瓜植株根际土中细菌和放线菌的数量,减少真菌和尖孢镰刀菌的数量,尤其以Yb1+Yb2菌悬液的处理效果最显著,对黄瓜枯萎病的发病率降低11.11个百分点,植株生物量增加56.7%。结论:菌株Yb1和Yb2具有生防潜力,两菌株配合运用效果更好。     

Some further characteristics of the growth of Naegleria fowleri and N. gruberi in axenic culture.

The effects of pH, various viscosity of the medium, changed ratio between the concentrations of dissolved and corpuscular components in the medium, and dissolved inorganic salts on the growth of axenic cultures of Naegleria fowleri and N. gruberi have been studied. The cultures were grown in liquid CALYG and BCS media. The pH optimum was 6.5 for N. fowleri and 6.0--6.5 for N. gruberi. No negative influence on the growth of N. fowleri was observed even at 0.5% concentration of highly viscous methylcellulose, whereas the growth of N. gruberi was distinctly inhibited by more than 0.2% of methycellulose. N. fowleri preferred the osmotorphic and N. gruberi phagotrophic nutrition in the given system of cultivation. The growth of both Naegleria species was inhibited by 0.1 N concentration of sodium chloride and potassium chloride without any significant difference in the tolerance. The inhibitory effect of these salts correlated primarily with the concentration of chloride anion. The ability to grow in a medium with increased viscosity and the preference for osmotrophic nutrtion are, besides the higher temperature optimum determined earlier, further characteristics of the pathogenic species N. fowleri.     

The influence of some growth retardants on the growth and mineral composition of plants

The influence of the growth retardants 3-chlorobenzyl-tri-n-butylammonium bromide (B₃), 4-chlorobenzyl-tri-n-butylammonium bromide (B₄), α-naphthylmethyl-tri-n-butylammonium bromide (α-NMB) and the commercial products 2-chloroethyltrimethylammonium chloride (chlormequat chloride) and N-dimethylaminosuccinamic acid (aminozide) on the growth characteristics and chemical composition of plants growing in soil under glasshouse conditions has been studied. The height, fresh and dry weights and content of nitrogen, phosphorus, potassium, calcium, magnesium, iron and manganese of treated plants were compared with those of control plants. The chlorophyll content of certain leaves was also estimated. The retardants markedly altered the growth habit of plants and usually led to a decrease in fresh and dry weights. The percentage of plant nutrient elements in the dry matter was increased by treatment.     

The effect of temperature on colony growth by Erysiphe sp. infecting Rhododendron

The growth and reproduction of powdery mildew pathogens is generally encouraged by increasing temperatures, up to 25°C. Germination and germ tube extension of Erysiphe sp. on Rhododendron cv. Elizabeth were optimal at 20°C for conidia originally formed at either 10 or 15°C. During a 50-day period of colony growth, the viability of conidia formed at 15°C declined but for those formed at 10°C it increased. The expansion of Erysiphe colonies over an initial 12-day period was favoured by incubation at 15°C compared with 10 or 20°C. In the first 8 to 10 days of growth, secondary and tertiary hyphae formed most rapidly at 20°C. After 12 days, expansion of colonies at 20°C was limited to the area initially infested by primary hyphae, whereas in colonies grown at 10 and 15°C secondary and tertiary hyphae had extended beyond the area first colonized. Small colonies of densely packed hyphae formed at 20°C compared with open spreading colonies observed at 10 and 15°C.     

The repression and stimulation of growth of Erysiphe sp. on Rhododendron by fungicidal compounds

Erysiphe sp. is a causal agent of powdery mildew on Rhododendron . A novel in vivo method permitting the screening of fungicides on woody plants is described. Eight fungicides were evaluated for activity against Erysiphe sp. using Rhododendron ponticum microplantlets grown in vitro. Pathogen development changed with both the type of fungicidal compound and the concentrations applied. The most active materials were fenpropidin and penconazole, which showed high activity at the lowest concentrations. Six of the compounds performed more effectively than a mixture of bupirimate + triforine (Nimrod T), the standard recommendation for control of this pathogen on Rhododendron . All fungicides affected the sporulation of Erysiphe sp., with propiconazole, pyrazophos and triadimenol causing a significant increase in sporulation at the lowest concentrations. At higher concentrations, sporulation was significantly reduced by all treatments. No phytotoxic effects were detected with any fungicide at any concentration. The growth of plantlets in most treatments showed no significant difference from the untreated controls. The results of the study are discussed in relation to strategies for control and the epidemiology of Erysiphe sp. infecting Rhododendron .     

Relative tolerances of wild and cultivated barleys to infection by Blumeria graminis f.sp. hordei (Syn. Erysiphe graminis f.sp. hordei). I. The effects of infection on growth and development

The two lines of wild barley, B19909 and I-17-40 and the cultivated barley, cv. Prisma used in this investigation were found to be the most susceptible to infection of 25 wild and four cultivated barley lines when exposed to the local population of Blumeria graminis f.sp. hordei. All three lines were susceptible during the early stages of growth but expressed some level of adult plant resistance although this level of resistance was significantly higher in line I-17-40 than in either of the other two.The relative tolerances of the lines to the mildew were determined by comparing the effects of infection on their growth and development in growth cabinet experiments. Mildew developed more slowly on line I-17-40 than on the other two lines and by the third week after inoculation, when mildew cover on B19909 and cv. Prisma had reached about 27%, only about 15% of the green leaf area of line I-17-40 was covered. Mildew continued to increase on line B19909 and cv. Prisma so that 6 weeks after inoculation it covered 40% of their leaf-blades. On line I-17-40 30% of the green leaf area was colonised by 4 weeks after inoculation but because of adult plant resistance coupled with the loss of the earlier infected leaves through senescence mildew cover then reduced falling to 15% by 6 weeks. Although total mildew biomass, measured as conidial production was higher on line B19909 than on cv. Prisma all its growth parameters were reduced less indicating that it was the more tolerant line. Conidial production on the lower susceptible leaves of line I-17-40 was slightly lower than on cv. Prisma yet the reaction of these leaves to infection was the same on both lines indicating that tissues of I-17-40 were slightly less tolerant than those of the cultivated barley. However, during the later stages of growth when its upper leaves expressed high levels of ‘adult plant resistance’ dry matter production in this line increased to levels higher even than in the controls. This capacity for compensatory photosynthesis ensured that by the end of growth few differences in any of the measured growth parameters between infected and uninfected plants of line I-17-40 were significant.The greater tolerance of line B19909 over the other two lines and of cv. Prisma over line I-17-40 during the early stages of growth appears to be due to a lower sensitivity to infection of those processes which regulate dry matter accumulation and its distribution around the plant.     

辣椒素的抑菌作用及其对某些保护酶活性的影响

 本文对辣椒素的抑菌作用和对寄主体内3种保护酶活性的影响进行了研究,结果表明3.57μg/mL-50.00μg/mL的辣椒素对辣椒枯萎病菌的菌丝生长都有明显的抑制作用,浓度愈高,抑制作用愈强。20μg/mL辣椒素对另外供试的8种病原菌的菌丝具有强烈的抑制作用,其中对番茄灰霉病菌抑制作用最强。辣椒素处理辣椒后1-6 d内,SOD、POD和CAT酶活性的平均增减比率值均明显高于对照,而且对根部和叶部3种保护酶活性的影响显著不同。     

三种杀螨剂对双尾新小绥螨后代生长发育和繁殖的影响

为明确杀螨剂对双尾新小绥螨Neoseiulus bicaudus后代生长发育及繁殖的影响,采用联苯肼酯、三唑锡和哒螨灵对土耳其斯坦叶螨Tetranychus turkestani的致死中浓度处理双尾新小绥螨雌成螨,测定其后代各发育阶段的存活率、发育历期、寿命、雌性比例及繁殖力,构建亚致死条件下双尾新小绥螨后代的年龄-龄期两性生命表并模拟其种群增长模型,分析不同杀螨剂亚致死效应对捕食螨后代的影响。结果表明,联苯肼酯处理能显著缩短双尾新小绥螨后代的未成熟期（4.81 d）,显著延长双尾新小绥螨后代雌成螨的寿命（45.43 d）,且对存活率、产卵前期、雌性比例和净增殖率无显著影响。三唑锡处理降低了双尾新小绥螨后代雌性比例（0.37）并显著降低了其后代净增殖率（15.91）,对未成熟期、产卵前期和雌雄成螨寿命均无显著影响。哒螨灵处理对双尾新小绥螨后代的未成熟期、存活率、雌成螨寿命、产卵前期、和雌性比例均未产生显著影响,仅显著延长了雌雄成螨寿命（51.22 d和44.23 d）。经所建Timing种群模型模拟,3种杀螨剂处理后双尾新小绥螨后代种群均可以继续增殖,经过60 d无限制增殖后,联苯肼脂处理的双尾新小绥螨后代种群数量是对照的1.62倍,达4 976头;哒螨灵处理（2 101头）和三唑锡处理（983头）的种群数量较对照分别减少了31.43%和67.92%。表明联苯肼脂对双尾新小绥螨后代影响较小,是较为安全的杀螨剂。     

The effects of temperature on zoospores of the crook root fungus Spongospora subterranea f.sp. nasturtii

The effect of temperature on the release, survival, encystment and infectivity of Spongospora subterranea f.sp. nasturtii zoospores released from diseased watercress roots was studied. There was rapid, synchronized release of zoospores at 20°C followed by a steep decline in zoospore numbers. A similar trend occurred at 10° C and 15° C, although fewer zoospores were released and the subsequent decline was more gradual. In contrast, at 5°C very low numbers of zoospores were released over the first 5 days. Subsequently, zoospore release increased rapidly over the following 3 days and zoospore numbers were maintained at relatively high levels for a further 6 days. This duration of high zoospore numbers at 5°C was due to prolonged survival rather than continual release. When a uniform zoospore suspension released at IOC was transferred to 20·C zoospore numbers were found to decline rapidly over 6 days; the decline was less rapid at 15° C and IOC, taking 9 and 15 days, respectively. At 5°C zoospore numbers decreased slowly. Few zoospores encysted on roots at 20° C but increased numbers were found at 15°C and 10°C. There were significantly more diseased roots at 10° C than at 5,15 or 20° C. The lowest number of diseased roots was found at 20° C. The correlation between increased seventy of the disease in the field during the winter months and the effect of temperature on zoospores of S. subterranea f.sp. nasturtii is discussed.     

The possibility of factors other than phytoalexin accumulation preventing fungal growth in the incompatible interactions of soybean with Phytophthora megasperma f. sp. glycinea

Soybean ( Glycine max ) cv. Harosoy 63 is resistant to race 1 and susceptible to race 9 of Phytophthora megasperma f. sp. glycinea (Pmg). In detached primary leaves inoculated with zoospores, growth of race 1 was completely suppressed 16 h after inoculation, while race 9 was unaffected. The amount of the phytoalexin glyceollin that accumulated, however, was not significantly different in either the incompatible or compatible interaction 16 h after inoculation. At the circumference of the inoculated area, a slight accumulation of phytoalexin was observed only in the incompatible interaction 20 h or more after inoculation. Tolerance of race 9 to the phytoalexin was significantly higher than that of race 1 when the phytoalexin was added to agar. Moreover, race 9 degraded glyceollin faster than race 1. On leaves inoculated at separate points with either race, the lesion associated with race 9 never colonized areas inoculated with race 1. These results suggest that factor(s) other than the accumulation of phytoalexin in soybean tissue might cause cessation of growth of Pmg.     

An experimental transmission of porcine strains of Blastocystis sp. in the laboratory mice and gerbils.

Outbred laboratory mice were successfully infected with porcine strains of Blastocystis sp. using faecal stages as well as stages from fresh or passaged cultures. In contrast, inbred BALB/c mice and gerbils were only rarely infected and the intensity of their infection was mostly negligible. Blastocystis sp. was never observed inside the host cells. These results indicate a low host specificity of Blastocystis sp. as well as different sensitivity of investigated hosts to Blastocystis sp. infection.     

The phytotoxicity of some phenolic metabolic products of Ophiostoma ulmi to ulmus sp.

The c₁₀ phenolic acids, 2,4-dihydroxy-6-acetonylbenzoic acid (1) and its 6-(1-hydroxyacetonyl) (2) and 6-pyruvyl (3) analogues, metabolic products ofO. ulmi on a chemically defined medium are also produced on elm tissue medium but are rapidly metabolised once the carbon source is exhausted. The phytotoxicity to cut shoots ofU. glabra andU. hollandica of these acids and their 4-0-methyl ethers (4–6 respectively) and of 4-hydroxyphenylacetic acid (7) has been investigated. None of the C₁₀ acids consistently caused wilting or leaf necrosis inU. glabra but all three were toxic toU. hollandica. Diaporthic acid (4) caused severe leaf necrosis in bothUlmus sp. and the phenolic acid (7) caused wilting and necrosis ofU. glabra shoots. Attempts to reproduce these effects in rootedU. glabra saplings were unsuccessful. Autoradiography ofU. glabra shoots treated with [¹⁴C]-labelled acids (2) and (4) showed a uniform distribution of radio-activity in the tissues, but the labelled acids could not be recovered. There is no evidence that the low molecular weight metabolic products ofO. ulmi are toxic to rooted saplings or proof that they are formed in vivo.Samenvatting De C₁₀ fenolzuren, 2,4-dihydroxy-6-acetonylbenzoëzuur (1) en haar 6-(1-hydroxy acetonyl) (2) en 6-pyruvyl (3) analogen, metabolische produkten vanO. ulmi in synthetisch medium, worden ook in medium bereid met iepeweefsel gevormd, maar worden snel omgezet als de koolstofbron uitgeput is. De fytotoxiciteit van deze zuren en hun 4-0-methylethers (4–6 respektievelijk) en van 4-hydroxyphenylazijnzuur (7) voor afgesneden scheuten vanU. glabra enU. hollandica werd onderzocht. Geen van de C₁₀ zuren veroorzaakten constant verwelking of bladnecrosen inU. glabra, maar alle drie waren toxisch voorU. hollandica. Diaporthinezuur (4) veroorzaakte ernstige bladnecrosen in beideUlmus soorten en het fenolzuur (7) veroorzaakte in beide verwelking en necrosen vanU. glabra scheuten. Pogingen om deze effecten in jongeU. glabra bomen te reproduceren mislukten. Autoradiografie vanU. glabra scheuten behandeld met [¹⁴C]-gemerkte zuren (2) en (4) vertoonde een uniforme verspreiding van radioactiviteit in de weefsels, maar de gemerkte zuren konden niet teruggewonnen worden.     

The effects of mild cacao swollen shoot virus strains N1 and SS365B on growth and yield of cacao

A field experiment started at the Cocoa Research Institute of Ghana in 2007 to investigate the effects of the cacao swollen shoot virus (CSSV) mild stains N1 and SS365B on growth and yield of mixed hybrid cacao (Theobroma cacao L.). Growth was significantly influenced by the duration of infection with the two CSSV mild strains. Slicing analyses showed no significant differences in stem circumference among treatments up to the third year of field data collection. However, from the fourth to the seventh year, growth of N1-inoculated cacao plants was significantly higher than that of SS365B-inoculated plants. Overall, growth did not differ significantly between cacao plants inoculated with mild strain and the non-inoculated plants. Contrary to some previous reports, yield of mild strain-inoculated cacao plants was significantly lower than that of the non-inoculated plants. Polymerase chain reaction was used to detect the presence of CSSV in randomly selected field samples. The implications of these results (based on field data collected from 2008 to 2014) in the management of cocoa swollen shoot virus disease in Ghana are discussed.     

Host and biotic factors affecting sporulation ofstemphylium botryosum f. sp. lycopersici on tomatoes and ofalternaria porri f. sp. sol ani on potatoes

Factors known to inhibit sporulation of bio trophic fungal pathogens were found to enhance sporulation of two necrotrophic fungi. The sporulating potential ofStemphyliurn botryosum f. sp.lycopersici on tomatoes and ofAlternaria porri f. sp.solani on potatoes increased with necrotization, reaching a maximum on dead leaves. Wetting the dead leaves for the whole period of incubation with increasing concentrations of glucose resulted in progressively decreasing sporulation of both pathogens. However, application of glucose during the first half of the incubation period inhibited sporulation ofS. botryosum f. sp.lycopersici on tomatoes only a little, and increased that ofA. porri f. sp.solani on potatoes. The capacity ofS. botryosum f. sp.lycopersici to sporulate on leaves lasted for 12 weeks at 29°C, and ofA. porri f. sp.solani for 12 weeks at 29°C and for over 21 weeks at 20°C. The results emphasized basic differences in sporulation between biotrophic and necrotrophic parasites. Specific techniques useful for studying sporulationin vivo are discussed.     

植物根际优良促生菌（PGPR）筛选及其接种剂部分替代化肥对玉米生长影响研究

通过测定植物根际促生菌株固氮酶活性、溶磷量、分泌植物生长素、对病原菌的拮抗作用及菌株生长速度,筛选出了5株具有较好促生特性的优良菌株.利用筛选的优良菌株研制复合接种剂,并于2009年和2010年进行田试,测定其部分替代化肥对玉米生长的影响.结果表明:利用筛选的优良促生菌研制的复合微生物接种剂符合《微生物肥料》NY227-94标准.施用接种剂替代20％ ～ 30％的化肥,玉米株高、地上植物量、穗长、穗粗、单位面积穗数、穗粒数和经济产量等均有提高.研制的微生物接种剂(菌肥+80％化肥),2010年大田推广使用,玉米增产9.86％,减少化肥投入、增产收入及直接经济效益分别为620.1元,hm-2、2 291.4元,hm-2和2 851.5元.hm-2.     

明孢盘菌属分类进展及其重要的病原菌种类

明孢盘菌属(Neofabraea)中很多种类是重要的植物病原菌。该属真菌分类历史较为复杂,系统发育关系也长期存在较大的争议。本文对明孢盘菌属的分类学研究历史做了系统回顾,包括属的建立、物种组成及其命名更替和系统发育,概述了该属重要的植物病原菌种类地理分布和经济为害性,讨论了该属真菌物种的传统分类方法及分子研究方法,指出了存在的问题及今后的研究方向。     

The morphology,behaviour and molecular phylogeny of Phytophthora taxon Salixsoil and its redesignation as Phytophthora lacustris sp. nov.

Since its first isolation from Salix roots in 1972, isolates of a sexually sterile Phytophthora species have been obtained frequently from wet or riparian habitats worldwide and have also been isolated from roots of Alnus and Prunus spp. Although originally assigned to Phytophthora gonapodyides on morphological grounds, it was recognized that these isolates, informally named P. taxon Salixsoil, might represent a separate lineage within ITS Clade 6. Based on phylogenetic analyses and comparisons of morphology, growth‐temperature relationships and pathogenicity, this taxon is formally described here as Phytophthora lacustris sp. nov. Isolates of P. lacustris form a clearly resolved cluster in both ITS and mitochondrial cox1 phylogenies, basal to most other Clade 6 taxa. Phytophthora lacustris shares several unusual behavioural properties with other aquatic Clade 6 species, such as sexual sterility and tolerance of high temperatures, that have been suggested as adaptations to riparian conditions. It appears to be widespread in Europe and has also been detected in Australia, New Zealand and the USA. It was shown to be weakly or moderately aggressive on inoculation to Alnus, Prunus and Salix. The extent of P. lacustris’ activity as a saprotroph in plant debris in water and as an opportunistic pathogen in riparian habitats needs further investigation. Its pathogenic potential to cultivated fruit trees also deserves attention because P. lacustris has apparently been introduced into the nursery trade.     

棉花枯萎病菌新生理型菌株的分子鉴定

 Fusarium oxysporum f.sp. vasinfectum(Fov)已报道有8个生理小种和一个澳大利亚生理型,在我国只报道有3、7、8号小种。前期研究发现,我国还有一个与3、7、8号小种具有较大遗传差异的Fov新生理型。本研究通过对3、7、8号小种和新生理型菌株的翻译延伸因子(EF-1α)基因序列比对分析,发现该新生理型菌株具有特异性碱基序列。根据这些特异性碱基序列,设计了一对针对新生理型菌株的特异性引物,并证明该引物可以特异性检测Fov新生理型菌株。利用该引物对采自河北省主要植棉区的77株Fov菌株进行筛选,鉴定出2株潜在的新生理型菌株。从这2个Fov菌株中克隆出EF-1α和β-tubulin基因序列,通过构建系统发育树,证明这2个Fov菌株为新生理型菌株,而且与澳大利亚生理型菌株具有较近的亲缘关系。本研究建立的分子检测方法可用于棉花枯萎病菌新生理型菌株的鉴定。     

The effects of diflubenzuron on the growth of insect cuticle

Cuticle consists of chitin microfibrils embedded in a matrix composed largely of hydrated proteins. The effect of diflubenzuron, an inhibitor of chitin synthetase, on the deposition of both these components is reviewed. The polymerisation reaction is but one step in the pathway leading to chitin microfibrils. Possibly interactions to other steps in the pathway serve to enhance the consequences of the inhibition. Such enhancement could help to explain the abrupt changes in the rate of chitin synthesis that can be observed as diflubenzuron is cleared from epidermal cells. Cuticle proteins differ widely in their ability to form a stable layer when chitin is largely absent. In the most stable regions, diflubenzuron has no effect on the amount or nature of the proteins deposited. In contrast, there are many regions where the deposition of solid cuticle is stopped, presumably because the proteins involved cannot form a coherent layer. Intermediate degrees of stability are found. There is an association between the regions of stability and those of high sclerotisation; though sclerotisation often takes place long after deposition. Even when the protein layer is fairly stable it may not be deposited in a regular manner. This statement is illustrated by electron micrographs of cuticle from the hind tibiae of adult locusts. These micrographs also show that diflubenzuron can affect epidermal cells. In normal cells the plaques are in contact with the newly secreted cuticle; they are still present but this contact is not maintained after treatment with diflubenzuron.