玉米大斑病菌孢子萌发和附着胞形成的影响因素研究

 Factors of influence on conidium germination and appressorium formation of Setosphaeria turcica,such as light condition,conidial concentration,nutrient resources and pH value of conidial suspension were studied.There was no significant difference among light treatments.The optimal pH for conidium germination and appressorium formation was 5.0 to 7.0.The exogenous nutrient sources were not the indispensable factors for conidium germination,but 5% sugar solution were more favorable for appressorium formation than the others.Low conidial concentration in suspension (conidia ≤ 10⁴/mL) was propitious to conidium germination and appressorium formation,which were inhibited significantly in higher concentration.It was suggested that the phenomenon was due to the self-inhibitor,a kind of lipophilic substance,existing in the site of conidium germination.     

广西黑皮冬瓜疫病的病原菌鉴定及其生物学特性

 Isolate PD1 of Phytophthora was isolated from diseased black pericarp wax gourd in Guangxi in 2005. The morphological and biological characters of the isolate were examined, and its sequence of ribosomal DNA-ITS was analyzed. The range of growth temperature of the isolate was 10-37℃ and the optimal one was 31℃. The pathogen was sensitive to 10 mg/kg of malachite green, and its ability for starch utilization was weak. A wide host range of the pathogen was confirmed by artificial inoculation. The sizes of sporangia were (37.5-71.7) μm×(20.8-47.5) μm (av. 55.0 μm×30.4 μm). Microcycle conidiation of the pathogen was observed. The pathogen was identified as Phytophthora drechsleri Tucker based on its morphological and biological characters as well as ribosomal DNA-ITS sequence.     

上海地区草莓炭疽病病原鉴定

 Seventeen isolates of strawberry anthracnose were obtained from Shanghai suburb. According to the temperature test for mycelial growth, these isolates were divided into two groups:one was strain CMf-04 with optimal temperature of 24℃, the other was including 16 strains with optimal temperature of 28℃, and most of which could produce sexual stage on PSA media, e.g. QPg-961. Conidia of CMf-04 were hyaline, unicellular, straight and fusiform, (12.1-16.4) μm×(3.6-5.4) μm. Conidia of QPg-961 were hyaline, unicellular and ovoid to oblong, (13.0-19.7)μm×(4.1-7.3) μm. On basis of morphologcal, biological characteristics and the sequences of ribosome rDNA ITS, isolate CMf-04 from the strawberry rotten fruits was identified as Colletotrichum acutatum; while all the other isolates from the diseased leaf stalks, runners and root crowns at strawberry plantlet propagation stage were belonged to Colletotrichum gloeosporioides. It proved that C. gloeosporioides was the main pathogen of the strawberry anthracnose in summer strawberry propagation fields in Shanghai and it is of significance for the breeding of resistant strawberry and its control.     

2008年我国部分麦区小麦白粉病菌群体对温度的敏感性

 The sensitivity of 113 isolates of wheat powdery mildew (Blumeria graminis f. sp. tritici) sampled from 6 provinces or cities in 2008 to temperature was tested by detached leaf segment method with setting up 5 different temperatures indoor. The results showed the mean ET₅₀ (which represents the temperature that is required to obtain 50% of the maximum effect) of all isolates tested was 23.02℃. ET₅₀ values of 17.70% isolates were more than 24℃. The highest and the lowest ET₅₀ of isolates were 25.22℃ and 19.42℃, respectively. There were a certain differences for isolates sensitivity to temperature among different provinces or cites. It was also found that when temperature increased during 22-26℃, the latent period of isolates prolonged, and the latent period of different isolates was different at the same temperature, too. These results will provide a reference for the oversummering division of wheat powdery mildew, as well as the effect of climate to the disease.     

Clonostachys rosea 67-1液生孢子形成及其抗性研究

 The growth and sporulation of Clonostachys rosea strain 67-1 in PD broth was observed and figured out. A large amount of submerged spores were obtained in shake flask with proprietary Czapek me-dium. Meanwhile, the colonies of strain 67-1were cultured in PDA plate and aerial spores were collected by elution. Resistances of submerged spores and aerial spores to high temperature, dry condition and UV treatment were determined. The results showed that the survival of the submerged spores kept in 60℃ for 30 min was 76.7%, while the aerial spores were hardly germinated in the same condition. After two weeks' drying treatment, the spore activities were 89.2% and 29.3%, respectively. Similarly, the activity of submerged spores was 72.6% and that of aerial spores was 19.7% when exposing to UV for 1 min. It is illuminated that deep submerged fermentation is more efficient than solid culture for strain 67-1 to produce chlamydospores, which act as main component in biopesticide mass production.     

灰枣红点软腐病病原菌的鉴定

 The damage and symptoms of jujube fruit soft rot in Xinzheng, Henan Province, were investigated from 2006 to 2008, and the pathogen was identified based on the morphological characteristics and the ITS se-quence of ribosome DNA. The results showed that the aerial mycelium of colony was white in color in the first four days, then turned gray after incubation on PDA for 5-6 d at 25℃ and became black two weeks later. The mycelia grew luxuriantly with velvet character. The pycnidium was flask-shaped with a height of 196.9μm and a width of 213.3μm on the avereage. The conidium was colorless with single cell and had the shape of spindle, its size was (15.0-20.0)μm× (4.5-6.5)μm. The conidiophore was fastigiate. The homology of ITS sequence of ribosome DNA between the tested strain NXK and Botryosphaeria dothidea (GenBank ac-cession number:AJ938005) reached 99.87%, with a difference of only two base pairs. Based on the results of both morphological characters and molecular identification, the pathogen of jujube fruit soft rot in Xinzheng was identified as B. dothidea (Moug. ex Fr.) Ces. et de Not..     

Spatial-temporal variations in near-surface soil freeze-thaw cycles in the source region of the Yellow River during the period 2002–2011 based on the Advanced Microwave Scanning Radiometer for the Earth Observing System(AMSR-E) data

Detecting near-surface soil freeze-thaw cycles in high-altitude cold regions is important for understanding the Earth's surface system, but such studies are rare. In this study, we detected the spatial-temporal variations in near-surface soil freeze-thaw cycles in the source region of the Yellow River(SRYR) during the period 2002–2011 based on data from the Advanced Microwave Scanning Radiometer for the Earth Observing System(AMSR-E). Moreover, the trends of onset dates and durations of the soil freeze-thaw cycles under different stages were also analyzed. Results showed that the thresholds of daytime and nighttime brightness temperatures of the freeze-thaw algorithm for the SRYR were 257.59 and 261.28 K, respectively. At the spatial scale, the daily frozen surface(DFS) area and the daily surface freeze-thaw cycle surface(DFTS) area decreased by 0.08% and 0.25%, respectively, and the daily thawed surface(DTS) area increased by 0.36%. At the temporal scale, the dates of the onset of thawing and complete thawing advanced by 3.10(±1.4) and 2.46(±1.4) days, respectively; and the dates of the onset of freezing and complete freezing were delayed by 0.9(±1.4) and 1.6(±1.1) days, respectively. The duration of thawing increased by 0.72(±0.21) day/a and the duration of freezing decreased by 0.52(±0.26) day/a. In conclusion, increases in the annual minimum temperature and winter air temperature are the main factors for the advanced thawing and delayed freezing and for the increase in the duration of thawing and the decrease in the duration of freezing in the SRYR.     

黄瓜霜霉病菌保存方法

 Pseudoperonospora cubensis(Berk. & M. A. Curtis) Rostovzev, the causal agent of cucumber downy mildew, is an obligate parasitic fungus. Up to now it can not be preserved on culture medium. In this study, the sporangia of P. cubensis were preserved in protective substances of 10% dimethyl sulfoxide plus 5% skim milk, 10% dimethyl sulfoxide plus 10% skim milk, sterilized water and leaves in vitro, and stored at -20℃, -70℃, and preliminary freezing at -20℃ for 24 h prior to -70℃ respectively. The results showed that the sporangia preserved in 10% dimethyl sulfoxide plus 5% skim milk, preliminary freezing at -20℃ for 24 h prior to -70℃ were still highly pathogenic after 12 months preservation. The percentage of germination of sporangia, incidence and disease index were 46%, 50.0% and 40.0 respectively 9 d after inoculation. This method solved the problem of P. cubensis preservation.     

苏云金芽孢杆菌晶体蛋白对北方根结线虫生物测定方法的建立和杀虫效果评价

 A bioassay procedure was developed to assess the toxicity of Bacillus thuringiensis crystal protein against Meloidogyne hapla,a root-knot nematode,under laboratory conditions.Reproducibility and precision of the bioassay results were optimal when forty 2nd stage juveniles were incubated in the dissolved crystal protein solution at 25℃,pH9.0 for 7 days.The juveniles were stained with 1% KMnO₄ for 2 hours or methylene blue solution for 1 hour to distinguish living and dead ones.By the bioassay procedure,the LC₅₀ value of strain YBT-1532 crystal protein against M.hapla was determined as 0.304±0.086 mg/mL(LC₅₀±1.96SE).Moreover,the strain YBT-1532 showed toxicity to Caenorhabditis elegans,a free-living nematode.All results indicated that YBT-1532 is a toxic strain to plant-parasitic nematode,and has the potential to control plant-parasitic nematode.     

Effects of long-term warming on the aboveground biomass and species diversity in an alpine meadow on the Qinghai-Tibetan Plateau of China

Ecosystems in high-altitude regions are more sensitive and respond more rapidly than other ecosystems to global climate warming.The Qinghai-Tibet Plateau(QTP)of China is an ecologically fragile zone that is sensitive to global climate warming.It is of great importance to study the changes in aboveground biomass and species diversity of alpine meadows on the QTP under predicted future climate warming.In this study,we selected an alpine meadow on the QTP as the study object and used infrared radiators as the warming device for a simulation experiment over eight years(2011-2018).We then analyzed the dynamic changes in aboveground biomass and species diversity of the alpine meadow at different time scales,including an early stage of warming(2011-2013)and a late stage of warming(2016-2018),in order to explore the response of alpine meadows to short-term(three years)and long-term warming(eight years).The results showed that the short-term warming increased air temperature by 0.31℃and decreased relative humidity by 2.54%,resulting in the air being warmer and drier.The long-term warming increased air temperature and relative humidity by 0.19℃and 1.47%,respectively,and the air tended to be warmer and wetter.The short-term warming increased soil temperature by 2.44℃and decreased soil moisture by 12.47%,whereas the long-term warming increased soil temperature by 1.76℃and decreased soil moisture by 9.90%.This caused the shallow soil layer to become warmer and drier under both short-term and long-term warming.Furthermore,the degree of soil drought was alleviated with increased warming duration.Under the long-term warming,the importance value and aboveground biomass of plants in different families changed.The importance values of grasses and sedges decreased by 47.56%and 3.67%,respectively,while the importance value of weeds increased by 1.37%.Aboveground biomass of grasses decreased by 36.55%,while those of sedges and weeds increased by 8.09%and 15.24%,respectively.The increase in temperature had a non-significant effect on species diversity.The species diversity indices increased at the early stage of warming and decreased at the late stage of warming,but none of them reached significant levels(P>0.05).Species diversity had no significant correlation with soil temperature and soil moisture under both short-term and long-term warming.Soil temperature and aboveground biomass were positively correlated in the control plots(P=0.014),but negatively correlated under the long-term warming(P=0.013).Therefore,eight years of warming aggravated drought in the shallow soil layer,which is beneficial for the growth of weeds but not for the growth of grasses.Warming changed the structure of alpine meadow communities and had a certain impact on the community species diversity.Our studies have great significance for the protection and effective utilization of alpine vegetation,as well as for the prevention of grassland degradation or desertification in high-altitude regions.     

斐济金棕叶斑病菌鉴定及生物学特性

斐济金棕（Pritchardia pacifica Seem.&;H.Wendl.）叶斑病主要发生在叶片。初期症状为病斑呈水渍状褪绿,后期病斑中央灰白色,病斑边缘有黄色晕圈。对斐济金棕叶斑病病菌进行形态学观察和生物学特性的测定结果表明：斐济金棕叶斑病菌鉴定为卵形弯孢［Curvularia ovoidea (Hiroe &; Watan.) Muntanola］,菌丝生长适宜温度20～35 ℃,适宜pH5～6;分生孢子萌发的适宜温度为25～40 ℃;最适碳源为麦芽糖;最适氮源为硝酸钠;分生孢子的致死温度为55 ℃。     

稗草生防菌新月弯孢菌株J15（2）的生物学特性

研究了分离自稗草上的一个致病菌新月弯孢Curvularia lunata菌株J15（2）的基本生物学特性。结果表明,该菌菌丝生长、产孢的最适温度为28～32℃,pH为6～8。菌丝生长对光照无要求,黑暗利于增加产孢量,培养至15d可达产孢高峰。碳、氮、磷和硫等元素是该菌菌丝体生长、产孢的必需元素,钾、镁和铁对菌丝体的生长、产孢有极大的促进作用。分生孢子萌发的适宜温度范围为20～35℃,最适温度28℃;适宜培养基初始pH值在4～10之间。在58℃下,分生孢子10min失活。     

辣椒褐斑病菌生物学特性研究

本文对辣椒褐斑病病原菌Cercospora capsici Heald et Wolf的生物学特性进行了研究,结果表明,不同的营养、温度、pH等条件对菌丝生长和孢子萌发有显著影响。病菌菌丝的生长以PDA培养基为最适;适宜温度为20~25℃,最适温度为25℃;最适pH为8.0~9.0,光照对菌丝生长没有明显的促进作用,菌丝致死温度及时间为55℃ 10 min。分生孢子萌发适宜碳源为1%的蔗糖溶液,适宜氮源为1%的甘氨酸溶液;孢子萌发适宜温度为20~30℃,最适温度25℃;最适pH为5~6,光照对孢子萌发没有明显的促进作用,分生孢子致死温度及时间为52℃10 min。     

阳春砂仁(Amomum villosum lour.)叶枯病菌基本生物学特性研究

 砂仁叶枯病菌生长发育温度是10~38℃,孢子发芽温度为5~38℃,而以20~35℃萌发较好。致死温度54℃ 10分钟。孢子萌发要求RH96%以上的高湿度,饱和湿度最佳。病菌在pH3.1~11.05之间都能生长,在pH5.22~10.13时产孢量较多,孢子萌发率则在pH5.0~8.0时为高。砂仁果浸出液能刺激孢子发芽。病菌存活期在16个月以上。该菌对多种单糖、双糖、多糖都能利用,而氮源则以硝态氮和氨基酸态氮利用较好,氨态氮抑制病菌生长。该菌对碳、氮源的利用还受光照条件的影响。     

羊肚菌菌盖干腐病病原菌鉴定及培养特性研究

菌盖干腐病是羊肚菌Morchella spp.出菇后发生最严重的病害之一,常给羊肚菌生产造成较大损失.为明确引起贵州六盘水地区羊肚菌菌盖干腐病致病菌种类,采用单孢分离法从六盘水地区3个羊肚菌栽培点的菌盖干腐病样品上分离到9个菌株.基于形态学及ITS和LSU基因序列分析将9个菌株鉴定为长孢卵单隔孢霉Diplo(o)spo...     

培养条件对柑橘黑斑病菌丝生长的影响

以南丰蜜桔黑斑病菌为实验材料,研究了不同生长环境下病原菌生物学特性。结果表明,病菌在5~35℃的范围内均能生长,25℃为菌丝生长的最适温度。适宜pH值范围为5~7,最适pH值为6;在不同培养基中,菌丝在PDA培养基上生长最快,在OA培养基上菌落周围产生一定量的黄色素;光照时间长短对菌丝生长几乎无影响。     

红海榄赤斑病病原菌鉴定及其生物学特性研究

 本文对来自红海榄(Rhizophora stylosa)赤斑病同一病斑上获得的2个菌株PⅠ-1和PⅡ-3进行了鉴定和生物学特性研究。结果表明,PⅡ-3菌株的致病力比PⅠ-1的稍强;2个菌株均具有一定的寄主专化性。经形态特征观察与rDNA-ITS序列分析,2个菌株均鉴定为异色拟盘多毛孢(Pestalotiopsis versicolor)。生物学特性测定结果表明,温度、pH值和光照对2个菌株菌丝生长及孢子萌发的影响差异不大,生长温度均为10~32℃(最适25℃),pH值为3.0~10.9(最适4.0);孢子萌发温度均为10~35℃(最适25~28℃),pH值为2.5~8.0(最适3.0);黑暗条件有利于2个菌株菌丝生长和孢子萌发。但2个菌株的产孢特性存在明显差异,其中PⅠ-1产孢的最适温度为28℃而PⅡ-3为20℃;PⅠ-1产孢的最适pH值为5.1而PⅡ-3为9.0;PⅠ-1产孢对光照不敏感,而PⅡ-3在黑暗条件下几乎不产孢。另外,在相似条件下,PⅠ-1产孢量比PⅡ-3大,而PⅡ-3菌丝生长速度比PⅠ-1快,孢子萌发率也比PⅠ-1高。由此可见,2个菌株PⅠ-1和PⅡ-3虽属于同一个种,但某些生物学特性存在一定的差异。     

枣果贮藏期红粉病菌鉴定及环境因子对其分生孢子萌发的影响

 在山西省临县、太谷县发现枣贮藏期红粉病,发病初期果实表面出现圆形或椭圆形的白色絮状霉点,后期形成较厚粉状霉层。从病样中分离获得2株代表性菌株,通过病原菌分离培养、致病性测定、形态学特征及ITS序列特征分析,确定引起枣贮藏期红粉病的致病菌为粉红单端孢(Trichothecium roseum)。适合该病菌分生孢子萌发的温度为20℃~25℃,相对湿度为大于75%,pH=4~10,致死温度为48℃、处理10 min。适宜芽管生长的温度为20℃~25℃,相对湿度为大于75%,最适pH=6。本研究结果可为枣贮藏期红粉病的诊断和防治措施的制定提供理论依据。     

白术枯斑病原鉴定、生物学特性及其对不同药剂的敏感性研究

 白术(Atractylodes macrocephala Koidz.)是浙江省传统中药材“浙八味”之一。近年来在磐安县白术主产区发生一种新的枯斑病。为明确致病菌及其生物学特性和对杀菌剂的敏感性,本研究通过病原菌分离培养、柯赫氏法则验证、形态学特征观察,及ITS、LSU、rpb2和tub2多基因序列分析,发现引起该枯斑病的病原菌为Phoma exigua。生物学特性测定表明:该菌菌丝生长的最适温度为28℃,最适pH为8,最适碳源与氮源分别为可溶性淀粉和蛋白胨;分生孢子萌发最适温度24℃、相对湿度100%;菌丝和分生孢子的致死温度分别为47℃和54℃。不同药剂敏感性测定结果表明:咯菌腈对该菌菌丝生长的抑制作用最强,EC₅₀为0.24 μg·mL^-1;吡唑醚菌酯和嘧菌酯对其分生孢子萌发具有较强的抑制作用,EC₅₀分别为0.10和0.16 μg·mL^-1。由P. exigua 引起的白术枯斑病为国内外首次报道。     

马唐生防真菌弯孢霉(Curvularia sp.)菌株QZ-200的生物学特性研究

 本文主要研究影响马唐生防菌弯孢霉(curvularia sp.)菌株QZ-200营养生长、孢子萌发及孢子形成的因子。该菌在SCS(黄豆粉-玉米粉-蔗糖)培养基上生长最好;生长温度为10~40℃,最适为28℃;pH为2~11,最适pH为6;在以葡萄糖为碳源、以磷酸氢二铵为N源的Czapek培养基上生长良好。分生孢子萌发的温度为10~45℃,最适为28~30℃,失活温度为52℃10min;pH为2~11,适宜为5~8;以自由水或饱和湿度条件下萌发率最高;1%蛋白胨、1%牛肉浸膏、0.1%的TW-80、1%马唐煎汁和0.2%的菜籽油溶液明显提高萌发速度。该菌孢子形成的温度为15~35℃,最适为28℃;连续光照比光暗12h交替处理更有利于产孢,黑光灯为最佳光源。