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1.
为探究大豆疫霉对寄主选择压力的响应及应对机制，采用在大豆植株上继代式连续接种大豆疫霉的方法研究了大豆疫霉与其寄主互作过程中毒力变化的现象。结果表明，大豆疫霉的毒力具有一定的可变性，但不同菌株毒力变异的能力存在差别；经过14代次的连续接种，得到了比出发菌株PMG3的毒性明显增强的菌株PMG3-vir。毒力结构测定显示，PMG3-vir与PMG3的毒力公式都为1b，1d，2，3a，3b，4，5，6，7。 相似文献
2.
目的:筛选出对辣椒疫霉菌具有高效拮抗作用的木霉生防菌株,研究其对辣椒菌菌丝体和卵孢子的作用机制,评价其应用于辣椒疫病的生防潜力。创新点:首次在超微结构水平上报道棘孢木霉菌菌丝能重寄生于辣椒疫霉菌的卵孢子,为木霉生防菌的应用提供了科学理论依据。方法:从土壤中分离木霉菌株,采用对峙培养法筛选木霉生防菌株。通过形态学和多基因序列(ITS、tef1和rpb2)进行鉴定,明确获得木霉菌株的种类。通过细胞学和超微结构观察,研究木霉生防菌对辣椒疫霉菌菌丝和卵孢子的拮抗机制。结论:本研究筛选出了对辣椒疫霉菌菌丝具有高效拮抗作用的一个木霉菌株(CGMCC 6422),被鉴定为棘孢木霉菌(Trichoderma asperellum)。细胞学和超微结构显示,该菌株能塌陷辣椒疫霉菌的菌落,通过缠绕和穿透辣椒疫霉菌的菌丝体,引起菌丝体解体;首次观察到该菌株能侵染辣椒疫霉菌的卵孢子,并引起卵孢子完全降解。综上所述,筛选出的木霉生防菌株CGMCC 6422具有应用于防治辣椒疫病的生防潜力。 相似文献
3.
从皖北不同地区采集土壤样品,利用宿主结瘤法获得大豆根瘤,并采用平板划线法分离不同地区大豆根瘤菌株,共31株,对其进行染料及化学药物抗性、耐酸碱性、生长温度范围、耐盐性、抗生素抗性等性状的研究。结果表明,从31个菌株中筛选出总体抗性水平最为突出的菌株AWCS 13-4,其表现抗染料及化学药物能力最强;在pH4-pH12条件下生长良好,具有较广的酸碱度适应范围;在50℃条件下,仍可以缓慢生长;在6.0%NaCl处理下仍能生长,显示出很强的耐盐能力;并且在供试5种抗生素的不同浓度条件下均生长良好,表现出极强耐抗生素的能力。 相似文献
4.
皖北地区优良大豆根瘤菌的筛选 总被引：1，自引：0，他引：1
利用采集于皖北不同地区分离获得的14株大豆根瘤菌与大豆品种"南农1138-2"进行匹配试验。结果表明,根瘤菌菌株AHM2B、ABL9-2、AWL26和AFL15与"南农1138-2"有较好的共生性,其中菌株AHM2B、ABL9-2对总根瘤数、根瘤干重、植株干重、株高的影响较大,菌株AWL26和AFL15对提高叶绿素含量和全氮量影响显著。综合试验结果认为以AHM2B和ABL9-2较其他菌株表现更为突出。 相似文献
5.
通过单因子实验,筛选得到了适合大豆疫霉拮抗细菌B048液体发酵的最佳碳源为玉米粉,最佳氮源为豆粕,最佳无机盐离子为氯化钠。通过正交实验确定了该培养基的最佳配比为：玉米粉5g／L、豆粕15g／L、氯化钠10g／L。在确定适合该菌株的培养基组分基础上,对其培养条件进行优化,结果表明：初始pH值为6．0,培养时间为48h,转速为180r／min时为该菌株的最佳培养条件。 相似文献
6.
通过单因子实验,筛选得到了适合大豆疫霉拮抗细菌B048固体发酵的最佳碳源为麸皮,最佳氮源为豆粕,最佳无机盐离子为氯化钠。通过正交实验确定了该培养基的最佳配比为:麸皮,豆粕和氯化钠的质量比为9:2:0.1。在确定适合该菌株的培养基组分基础上,对其培养条件进行优化,在250mL的锥形瓶里装料量为22g,结果表明:培养时间为48h,培养温度为37℃,初始水量为65%,最佳接种量为20%时为该菌株的最佳培养条件。 相似文献
7.
8.
《蒙自师范高等专科学校学报》2016,(2)
为了筛选对环境友好的生防细菌防治三七疫霉病,通过高温处理、稀释涂布法分别从三七健康及患病植株根际土壤分离了21和16株可培养细菌,并以对峙培养法分别筛选到6和7株拮抗菌株,上述13株拮抗菌株经生理生化特征鉴定为芽孢杆菌属。结果表明,健康植株根际土壤有较丰富的可培养细菌,而患病植株根际土壤可培养细菌中的拮抗菌株较丰富,表明健康植株与患病植株根际土壤的拮抗细菌丰度发生了变化。解淀粉芽孢杆菌B1的抑菌带宽达8.5mm,具有一定的潜在生防价值。 相似文献
9.
采用CR-YMA培养基对新鲜的大豆根瘤提取物进行根瘤菌的分离、纯化培养,获菌落为圆形乳白色,表面凸起,直径0.4～0.5cm,革兰反应阴性,显微观察显示为短杆状的根瘤菌26株,并对26个菌株进行蛭石盆栽试验,接种效果显示:接种根瘤菌的大豆植株都有结瘤;与对照相比在结瘤数、鲜瘤重、瘤干重及植株地上部分干重分别增加了14.6%～1330.4%,6.3%～461.9%,28.6%～492.9%,10.2%～86.3%,植株全氮量在9.188%和12.563%之间。初步筛选出与大豆品种"南农1138-2"最佳共生匹配的根瘤菌菌株分别是:AF1、AF9、AH10。 相似文献
10.
峨眉山珙桐根际和非根际土壤微生物的初步研究 总被引：1，自引：0，他引：1
以四川峨眉山珙桐林为研究对象,选取珙桐林珙桐根际和非根际两种土壤样品,分别进行微生物的分离、测数,并根据菌株形态、培养特征和生理生化特性等,对根际和非根际土壤中的细菌、放线菌和真菌进行了初步鉴定.结果表明:从珙桐根际和非根际土壤中共得到细菌菌株85株,分属于9个属;放线菌菌株28株,分属于2个属;真菌菌株13株,分属于5个属.同一地区珙桐根际和非根际土壤中,珙桐根际土壤中的微生物的总数以及细菌、放线菌和真菌数量均低于非根际土壤. 相似文献
11.
来自南阳玉米穗腐病样品的玉蜀黍赤霉菌的分离及其特性鉴定 总被引：1，自引：1，他引：0
2009年在河南省西峡县、唐河县采集得到玉米穗腐病样品,样品经病原分离和单孢子纯化后,得到3个菌株Gz1、Gz2与Gz3（GenBank登记号分别为：HM769949、HM769950与HQ110051）.在致病性测定的基础上进行了rDNA-ITS序列分析,其结果表明3个菌株均与玉蜀黍赤霉菌（Gibberella zeae）有99%的同源性,用软件MEGA version 4.0构建基于r DNA-ITS序列系统发育树,3个菌株均与玉蜀黍赤霉菌在100%boostrap水平相聚于同一群;菌株Gz1、Gz2与Gz3的菌落形态和分生孢子特征均与文献描述的玉蜀黍赤霉菌相符.为此实验选取了Gz1作为代表性菌株对玉蜀黍赤霉菌的部分生物学特性做了研究. 相似文献
12.
辣椒青枯病拮抗细菌的筛选及其鉴定 总被引：8，自引：0，他引：8
从河南扶沟、江苏南京和淮阴等地的辣椒、番茄和黄瓜植物根围土壤中分离到100个细菌菌株.采用抑菌圈-定殖力双重测定法,筛选出5株终定植密度大于104cfu/g根、抑菌能力较强的细菌菌株;并对5个生物防治菌进行了生理生化测定.结果表明,5个生物防治菌分别属芽孢杆菌属、沙雷氏菌属、假单孢菌属和肠杆菌属. 相似文献
13.
根据不同的土壤类型,从江苏省苏北地区6市采集土样422份,分离出苏云金杆菌76株.血清学分析表明,它们分属于H_3、H_7、H_10、H_21和H_43型,另一株为自凝菌.通过对76个分离株的生物毒力测定,筛选出4林对赤松毛虫、小菜蛾、玉米螟等具有高毒力的菌株,为开发高效苏云金杆菌杀虫剂提供了重要的菌种资源. 相似文献
14.
南阳市玉米穗腐病致病镰刀菌种群结构分析 总被引：1，自引：0，他引：1
镰刀菌是玉米穗腐病的主要病原菌.本研究对南阳市5县2009年夏玉米穗腐病致病镰刀菌的种群结构进行调查分析.从病样中按常规组织分离法进行病原菌分离,对分离物经单孢分离纯化后根据柯赫法则进行致病性检测,并根据形态特征和核糖体基因内转录间隔区（rDNA-ITS）序列对病原菌进行鉴定.从采集的80份穗腐病样品中分离获得105株镰刀菌,接种结果表明,所有菌株对玉米均有致病性.形态和分子鉴定结果表明,引起南阳市玉米穗腐病的镰刀菌至少有4种：层出镰刀菌Fusarium proliferatum、串珠赤霉菌Gibberella monoliformis、木贼镰刀菌F.equiseti及玉蜀黍赤霉菌G.zeae.南阳市玉米穗腐病致病镰刀菌以层出镰刀菌为优势种,串珠赤霉菌为次优势种. 相似文献
15.
Michael Windle Carol Miller-Tutzauer Grace M. Barnes John Welte 《Child development》1991,62(1):179-189
Adolescent perceptions of help-seeking social resources (e.g., parents, friends, school counselor, clergyman) they would utilize if they were having substance abuse difficulties were investigated for samples of early and middle adolescents. 8 different perceived help-seeking categories were identified, and intergroup comparisons were made with regard to gender and ethnic/racial group and with regard to alcohol consumption, substance-related problems, and school misconduct. 2 perceived help-seeking categories had the highest levels of problem behaviors. The first category consisted of adolescents who identified friends as the only social resource they would utilize if they were having substance abuse problems. The second category, referred to as social isolates, indicated that they would not utilize any social resource if they were having substance abuse problems. There were approximately twice as many male social isolates as female social isolates, and blacks and Hispanics were highly overrepresented in the social isolate category. 相似文献
16.
Chen-jian Liu Fu-ming Gong Xiao-ran Li Hai-yan Li Zhong-hua Zhang Yue Feng Hiroko Nagano 《Journal of Zhejiang University. Science. B》2012,13(4):298-306
This research was aimed at isolating and identifying the predominant lactic acid bacteria (LAB) in the traditional Chinese
salt-fermented soybean food, douchi, from Yunnan, China. The predominant LAB present were isolated and identified by conventional
culture-dependent methods combined with molecular biological methods. Two hundred and sixty isolates were obtained from thirty
kinds of traditional fermented douchi from six cities and counties in Yunnan, and those strains were divided into twelve groups
by their morphological and biochemical characteristics. Based on 16S ribosomal DNA (rDNA) sequencing and analysis, 56 representative
strains were identified as belonging to 6 genera and 14 species: Lactobacillus (4 spp.), Weissella (3 spp.), Pediococcus (2 spp.), Staphylococcus (2 spp.), Enterococcus (1 sp.), and Bacillus (2 spp.). The results show that douchi contains a large natural population of LAB of diverse composition from which some
strains could be selected as starters for functional fermented foods. This is the first study on the original douchi from
Yunnan, and the results suggest that it may be a useful source for the isolation of LAB. This study has also laid a foundation
for further research on developing functional douchi products. 相似文献
17.
Compton DL Gilbert JK Jenkins JR Fuchs D Fuchs LS Cho E Barquero LA Bouton B 《Journal of learning disabilities》2012,45(3):204-216
Response-to-intervention (RTI) approaches to disability identification are meant to put an end to the so-called wait-to-fail requirement associated with IQ discrepancy. However, in an unfortunate irony, there is a group of children who wait to fail in RTI frameworks. That is, they must fail both general classroom instruction (Tier 1) and small-group intervention (Tier 2) before becoming eligible for the most intensive intervention (Tier 3). The purpose of this article was to determine how to predict accurately which at-risk children will be unresponsive to Tiers 1 and 2, thereby allowing unresponsive children to move directly from Tier 1 to Tier 3. As part of an efficacy study of a multitier RTI approach to prevention and identification of reading disabilities (RD), 129 first-grade children who were unresponsive to classroom reading instruction were randomly assigned to 14 weeks of small-group, Tier 2 intervention. Nonresponders to this instruction (n = 33) were identified using local norms on first-grade word identification fluency growth linked to a distal outcome of RD at the end of second grade. Logistic regression models were used to predict membership in responder and nonresponder groups. Predictors were entered as blocks of data from least to most difficult to obtain: universal screening data, Tier 1 response data, norm referenced tests, and Tier 2 response data. Tier 2 response data were not necessary to classify students as responders and nonresponders to Tier 2 instruction, suggesting that some children can be accurately identified as eligible for Tier 3 intervention using only Tier 1 data, thereby avoiding prolonged periods of failure to instruction. 相似文献
18.
Liu XIE Jing-ze ZHANG Yao WAN Deng-wei HU 《Journal of Zhejiang University. Science. B》2010,11(1):61-70
Strawberry anthracnose, caused by Colletotrichum spp., is a major disease of cultivated strawberry. This study identifies 31 isolates of Colletotrichum spp. which cause strawberry anthracnose in Zhejiang Province and Shanghai City, China. Eleven isolates were identified as C. acutatum, 10 as C. gloeosporioides and 10 as C. fragariae based on morphological characteristics, phylogenetic and sequence analyses. Species-specific polymerase chain reaction (PCR) and enzyme digestion further confirmed the identific... 相似文献
19.
目的：对思茅松松塔的化学成分进行初步研究。方法：采用溶剂法提取思茅松松塔的化学成分,运用正相硅胶、反相RP-18、Sephadex LH-20柱色谱和中压液相色谱等方法进行分离纯化,利用波谱数据鉴定化合物的结构。结果：从中分离鉴定了6个化合物,分别为：松脂醇（1）,罗汉松树脂酚（2）,（7S,8R）-3’,4,9,9’-四羟基-3-甲氧基-7,8-二氢苯并呋喃-1’-丙醇基新木脂素（3）,dihydrodehydrodiconiferyl alcohol（4）,二氢槲皮素-3’-O-β-D-吡喃葡萄糖苷（5）,3,4-二羟基苯甲酸（6）。结论：6个化合物均首次从该植物中分离得到。 相似文献