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1.
新疆额尔齐斯河流域“2005•6•1”大洪水分析   总被引:1,自引:1,他引:0  
2005年6月1-2日,额尔齐斯河全流域发生了突发性融雪和降雨混合型大洪水,各支流洪水峰高、量大、来势凶猛,其中额尔齐斯河源头支流--库依尔特斯河发生有实测资料(50 a)以来最大洪水,布尔津河、哈巴河发生有实测资料(54 a)以来第2、第3位洪水,给当地造成较大经济损失。根据河流实测洪水、降水量、气温、高空和环流形势等资料,对这次洪水的成因、过程、特点进行分析。结果表明:① 在额尔齐斯河流域融雪与降雨混合型大洪水的形成过程中,前期气温和大尺度降水天气起重要作用;② 从[JP2]有实测洪水记录的50多年以来,第4次发生全流域性洪水,在全球气候变暖和随阿勒泰地区冬季降水量明显增多的形势下,灾害性洪水出现的可能性将增加;③ 由于融雪与降雨混合型洪水过程较长、峰量较大,因此,洪水挟沙能力较强,在设计蓄水工程时要引起重视;④ 对下游有较大城市或重点水利工程的山区河流,要加强防洪预警系统的建设力度,以减轻灾害性洪水造成的损失。  相似文献   

2.
BABA induced local and systemic resistance in lettuce (Lactuca sativa) against the Oomycete Bremia lactucae. Structure-activity analysis showed no induced resistance by related amino-butanoic acids or β-alanine. The R-enantiomer of BABA induced resistance whereas the S-enantiomer did not, suggesting binding to a specific receptor. Other compounds known to be involved in SAR signaling, including abscisic acid, methyl-jasmonate, ethylene, sodium-salicylate and Bion® (BTH) did not induce resistance. Systemic translocation of 14C-BABA and systemic protection against downy mildew were tightly correlated. BABA did not affect spore germination, appressorium formation, or penetration of B. lactucae into the host. Epifluorescence and confocal microscopy revealed that BABA induced rapid encasement with callose of the primary infection structures of the pathogen, thus preventing it from further developing intercellular hyphae and haustoria. Invaded host cells treated with BABA did not accumulate phenolics, callose or lignin, or express HR. In contrast, cells of genetically-resistant cultivars accumulated phenolics, callose and lignin and exhibited HR within one day after inoculation. The callose synthesis inhibitor DDG did not inhibit callose encasement nor compromised the resistance induced by BABA. PR-proteins accumulated too late to be responsible for the induced resistance. DAB staining indicated that BABA induced a rapid accumulation of H2O2 in the penetrated epidermal host cells. Whether H2O2 stops the pathogen directly or via another metabolic route is not known.  相似文献   

3.
Daylily rust fungus, Puccinia hemerocallidis, was proven to host-alternate between a wild daylily, Hemerocallis fulva var. longituba, and a patrinia, Patrinia villosa. No proof was obtained for the early belief that the fungus is pathogenic to plantainlilies, Hosta species, in addition to daylilies, Hemerocallis species. The fungus seems to alternate regularly between daylilies and patrinias in Japan because most daylily species are deciduous, and a vegetatively reproducing stage of the pathogen does not seem capable of successfully overwintering free of the living host tissue.  相似文献   

4.
在水稻直播田用38%苄·丙·异WP25~50g/667m^2,不仅对稗草、千金子有特效,而且对稻田常见的鸭舌草、节节菜、异型莎草、陌上菜、牛毛毡等杂草均有很好的防除效果。38%苄·丙·异WP易对水稻秧苗产生不同程度白化现象,但后期会恢复,对秧苗素质及分蘖无不良影响。  相似文献   

5.
大棚菜的“二害”即肥分危害 ,高温危害。对大棚菜产量、产值影响很大 ,防治措施如下 :一、肥分危害的防治1.深施肥料。化肥宜深施或溶解在水中施。2.适量施肥。大棚内流失少 ,施肥量原则上低于露地蔬菜。3.施熟有机肥。施用有机肥 ,特别是人畜粪尿或栏肥要充分腐熟发酵后施用。4.适时换气。不管施用哪种肥料 ,皆不宜于傍晚进行 ,施肥后要加强通风换气 ,夜间也要保持一定的通风量 ,以防止肥料分解时产生有害气体在棚内积累 ,对蔬菜产生毒害。5.施肥距离要适宜。追施尿素等速效肥料不宜离蔬菜根部太近 ,以防烧根。作叶肥施用 ,浓度…  相似文献   

6.
Elaeocarpus yellows” (ELY) is a widely reported phytoplasma disease of Elaeocarpus zollingeri trees in Japan. The phytoplasma associated with ELY (ELY phytoplasma) had not been identified at the species level because its 16S rRNA sequence had yet to be reported. Here, we report the results of a sequence analysis based on 16S rRNA and secA gene sequences, which showed that the ELY phytoplasma is related to ‘Candidatus Phytoplasma malaysianum’. To our knowledge, this is the first report showing the occurrence of ‘Ca. P. malaysianum’ outside Malaysia and the infection of E. zollingeri by the phytoplasma.  相似文献   

7.
本产品对害虫除具有胃毒和触杀作用外,还具有较强的渗透作用,同时对害虫有黏着性,用于防治十字花科蔬菜菜青虫。  相似文献   

8.
9.
使用高空和地面定时观测资料、区域站降水资料、云图和NCEP 1°×1°再分析资料,对2011年6月15-16日敦煌暴雨的影响系统、干侵入、垂直涡度收支、视热源和视水汽汇进行了分析。结果表明:这次暴雨是中高纬度天气系统与低纬度天气系统相互作用,在敦煌附近上空形成中尺度涡旋造成的结果。在低涡生成初期,低涡南侧对流层高层有明显的干侵入发生;低涡快速发展期,干侵入达到最强;对流层中下层辐散作用项对垂直涡度正贡献最大,在对流层中层水平平流项和垂直输送项对垂直涡度正贡献起主要作用;低涡成熟期,干侵入开始减弱。对流层下层辐散作用项对垂直涡度正贡献进一步加强,对流层中层水平平流项正贡献作用减弱,垂直输送项正贡献作用增强。视热源与视水汽汇加热强度变化与低涡发生、发展的不同阶段紧密相关,视热源、视水汽汇中心与垂直上升运动中心相对应,说明大气加热与大气上升运动密切相关,水汽凝结潜热释放加速垂直上升运动,垂直输送在视热源、视水汽汇中起主要作用。  相似文献   

10.
Spinach is one of the most nutritious green-leaf vegetables. In the spinach production, diseases cause a significant loss in both yield and quality. Improving disease resistance is one of the major challenges in spinach breeding. Arabidopsis nucleoporin CONSTITUTIVE EXPRESSER OF PATHOGENESIS-RELATED GENES 5 (CPR5) functions as a negative regulator of plant cell death and immunity as cpr5 mutant exhibits spontaneous cell death and heightened immunity. In addition, CPR5 play a role in trichome development as the majority of cpr5 mutant trichomes are branchless whereas wild type trichomes are often three-branched. In the spinach genome, we identified a homolog of Arabidopsis CPR5, referred to as Spinacia oleracea CPR5 (SoCPR5). To investigate the function of SoCPR5, we introduced SoCPR5 into Arabidopsis cpr5 mutant. Our data showed that both spontaneous cell death and heightened immunity were suppressed in the SoCPR5-transgenic cpr5 mutants, verifying that SoCPR5 functions as its Arabidopsis counterpart in plant cell death and immunity. SoCPR5 also fully restored wild type trichome phenotype of the cpr5 mutant. Our study therefore indicates that the function of SoCPR5 is conserved between plant species and SoCPR5 can be applied for genetic manipulation of plant immunity in spinach.  相似文献   

11.
Four Rhododendron hybridum plants (from cvs Moravanka and Don Juan), all exhibited symptoms of shortened axillary shoots, reduced leaves with vein clearing and yellowing, undeveloped flowers, and general stunting in a rhododendron nursery garden in southern Bohemia in 2007. Electron microscopy examination of ultra-thin sections revealed the presence of numerous polymorphic phytoplasma-like bodies in the phloem tissue of leaf midribs and petioles. The phytoplasma etiology of this disease was further confirmed by polymerase chain reaction (PCR) using universal phytoplasma primers. Restriction fragment length polymorphism (RFLP) analysis of amplification products obtained with a R16F2/R16R2 primer pair from all symptomatic plants indicated the presence of phytoplasma from the 16SrVI-A subgroup. A detailed comparison of the amplified sequences and phylogenetic analysis confirmed that the phytoplasma belonged to the subgroup 16SrVI-A (clover proliferation phytoplasma group). This is the first report of the natural occurrence of ‘Candidatus Phytoplasma trifolii’ in plants of Rhododendron hybridum.  相似文献   

12.
The Rhizoctonia solani species consists of multinucleate isolates that belong to anastomosis groups AG1–AG3 and differ in virulence and host affinity. R. cerealis is a binucleate species of anastomosis group AG-D which causes sharp eyespot, a common plant disease in Poland. Rhizoctonia spp. is a ubiquitous soil pathogen that poses a significant threat for global crop production due to the absence of effective crop protection products. The aim of this study was to determine the virulence of R. solani and R. cerealis isolates towards Beta vulgaris, Zea mays, Triticum spelta and T. aestivum seedlings, to confirm the presence of endopolygalacturonase genes pg1 and pg5 in the genomes of the tested isolates and to evaluate the tested isolates’ sensitivity to triazole, strobilurin, imidazole and carboxamide fungicides. All tested isolates infected B. vulgaris seedlings. but none of them were virulent against Z. mays plants. R. solani isolates AG4 PL and AG2-2IIIB PL were characterized by the highest virulence (average infestation score of 2.37 and 2.53 points on a scale of 0–3 points) against sugar beet seedlings. The prevalence of infections caused by most of the analysed isolates (in particular R. solani AG4 J—11.8, and R. cerealis RC2—0.78) was higher in spelt than in bread wheat. The virulence of the analysed isolates was not correlated with the presence of pg1 and pg5 genes. The efficacy of the tested fungicides in controlling Rhizoctonia spp. infections was estimated at 100% (propiconazole + cyproconazole), 98.8% (penthiopyrad), 95.4% (tebuconazole) and 78.3% (azoxystrobin).  相似文献   

13.
“高氯·斜夜核”悬浮剂是由武汉武大绿洲生物技术有限公司推出的高科技、新型昆虫病毒杀虫剂,由斜纹夜蛾核型多角体病毒与高效氯氰菊酯及增效助剂配制而成。高效氯氰菊酯可快速击倒害虫,使其立即停止为害,并使害虫的免疫力下降有利于病毒的感染,病毒则可象“禽流感”一样具有传染性,害虫一旦感染病毒,将患上“绝症”。  相似文献   

14.
Mexico is considered to be one of the centers of origin of grain amaranth species. Recently, plants with abnormal anatomical features were observed in experimental fields established in Central Mexico. The most noticeable symptoms, which consisted of excessive stem and bud proliferation, mosaics and unusual coloration, suggested that they might be phytoplasma-induced disorders. Thus, different accessions of grain amaranth (Amaranthus hypochondriacus and A. cruentus) plants were subjected to polymerase chain reaction (PCR) analysis specifically designed to detect these pathogens. Two universal phytoplasma-specific primer pairs were tested in a nested PCR assay, with primer pair P1/tint (followed by primer pair R16F2/R16R2). Further DNA sequencing analysis of the resulting amplicons indicated that these phytoplasmas may be related to others already affecting important agricultural crops in Mexico, such as soybean. Data are presented that disclose the etiology of these syndromes by the use of molecular techniques. To the best of our knowledge, this finding constitutes the first report of a phytoplasma-related disease in grain amaranth.  相似文献   

15.
Attract-and-kill techniques, associating an attractant and a contact insecticide in a sticky formulation, are a new way of controlling Lepidopteran pests. Insecticide resistance may, however, limit the effectiveness and even the attractiveness of such formulations where resistance pleiotropic effects influence pheromone perception. We have tested this hypothesis on resistant codling moths Cydia pomonella (L) using a commercial formulation containing (E,E)-8,10-dodecadien-1-ol (codlemone), the major component of the sex pheromone, as an attractant and permethrin as toxicant. We first compared the attractiveness of codlemone in a wind tunnel and the contact toxicity of pyrethroids on males of one susceptible and of three strains selected for resistance to diflubenzuron, deltamethrin and azinphos-methyl. The dose-response relationships of males of susceptible and resistant strains to codlemone did not differ significantly. The deltamethrin-selected strain was the most resistant to pyrethroids, exhibiting 138-, 25- and 18-fold resistance ratios to deltamethrin, cypermethrin and permethrin, respectively. The efficiency of the attracticide formulation, applied successively on filter paper support, glass support and wood support, was estimated by recording the mortality delay of males after natural contact with the formulation in the wind tunnel. The deltamethrin- and diflubenzuron-resistant strains were significantly less affected than the susceptible strain by contact with the attracticide on the wooden support, exhibiting 58- and 2.3-fold greater LT50 ratios, respectively. Mortality of deltamethrin-resistant moths did not exceed 40% after 48 h. The LT50 value was significantly greater on filter paper support than on the two other supports. Surprisingly, the LT50 ratio of the deltamethrin-resistant strain was markedly higher on filter paper support (1021-fold), which was more absorbent, than on the glass support (31-fold). No sublethal effects in terms of pheromone response, mating or fecundity occurred in moths surviving contact with the attracticide. Choice of insecticides in attracticide formulations will be influenced by the resistance background of the target pests. Principles of insecticide resistance management may also be applied to attract-and-kill technology by alternating with other insecticides or control methods.  相似文献   

16.
磺草酮·烟嘧磺隆·莠去津24%悬浮剂是玉米田除草剂,主要用于玉米苗后处理,防治一年生杂草。为明确磺草酮·烟嘧磺隆·莠去津24%悬浮剂对玉米田杂草的防除效果及对玉米的安全性,经济有效的用量,2007年进行了田间药效试验,取得了良好的效果。  相似文献   

17.
20%甲维·毒死蜱WP系溧阳中南化工有限公司经科学筛选合理配制的一种广谱、高效、剂型先进的杀虫剂。该产品主要特点:①具有良好的触杀、胃毒作用,有一定的熏蒸作用;②增效作用显著,两种农药混配后,室内毒力测定,共毒系数达149.64;③不易产生抗性;④产品粘着力和渗透性好,耐雨水冲刷;⑤光解速度较同类产品其它剂型慢。防治作物及对象:水稻稻纵卷叶螟、甘蓝蔬菜小菜蛾。使用技术:防治稻纵卷叶螟、  相似文献   

18.
Bacterial canker is an economically important disease of tomato. Resistance induced by DL-β-Amino butyric acid against bacterial canker caused by Clavibacter michiganensis ssp. michiganensis in tomato plants was investigated. Different doses of DL-β-Amino butyric acid (250–1000 μg ml−1 doses) were tested on 3-week old plants inoculated with a 108 CFU ml−1 bacterial suspension, and disease development was evaluated after inoculation and treatment. Although in vitro growth of the bacteria was not affected by DL-β-Amino butyric acid treatment, foliage sprays of 500 μg ml−1 DL-β-Amino butyric acid significantly suppressed disease development up to 54% by day 14 after inoculation at the four different doses tested. Bacterial populations were reduced by 84% in BABA-treated plants compared to water-treated plants by day 4 after inoculation. Inoculated BABA-treated plants showed significantly higher phenylalanine ammonia-lyase activity, peroxidase activity, and H2O2 concentration than inoculated water-treated plants during day 1 after treatment. These findings suggest that the DL-β-Amino butyric acid treatment resulted in an increase of these enzymes and in H2O2 concentration in planta, and was associated with induction of resistance to bacterial canker.  相似文献   

19.
The morphology of apple and pear stigma was investigated with confocal laser scanning microscopy and scanning electron microscopy. The floral colonization process by Erwinia amylovora was studied with gfp-labelled bacteria and confocal laser scanning microscopy to allow the in vivo observation of the pathogen colonization on intact, viable plant tissues without any kind of staining of the specimens. The interaction on the stigma between Erwinia amylovora and Pantoea agglomerans, both labelled with genes encoding for fluorescent proteins (DsRed-GFP), was also investigated. A stylar groove, covered by papillae and dwelling from the stigma along the style, was visualized. In laboratory conditions, this groove was shown to be an important way for E. amylovora migration towards the nectarthodes. Due to its anatomical structure the groove can sustain bacterial multiplication and thus may play an important role on the interactions between the pathogen and the bacterial antagonist P. agglomerans.  相似文献   

20.
田间试验结果表明,氟.精.灭30%乳油使用剂量为70~100g/667m^2,(315~450g.a.i/hm^2)在大豆1~3复叶期,杂草2~5叶期茎叶喷雾处理,对夏大豆田阔叶杂草和禾本科杂草均有较好的防除效果,并且有较长的持效期,对大豆生长安全。  相似文献   

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