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91.
为探究氮沉降对干旱区高寒湿地土壤线虫群落结构的影响,本研究以天山中部的巴音布鲁克天鹅湖高寒湿地为样地,选取2个不同水分条件区域,分别喷施3个不同浓度氮素,开展野外原位模拟氮沉降控制试验,研究不同水分条件土壤线虫群落结构对氮沉降的响应。结果表明:地表季节性积水条件土壤线虫群落的优势属主要为前矛线属(Prodorylamus,29.30%),地表常年干燥条件土壤线虫群落的优势属是前矛线属(Prodorylamus,18.69%)、Laimydorus(20.21%)和螺旋属(Helicotylenchus,33.48%);在土壤水分和氮添加的共同作用下,杂食/捕食类线虫(OP)和食真菌类线虫(FU)丰度升高,植物寄生类线虫(PP)丰度降低;地表常年干燥条件下,氮添加对土壤线虫群落各生态指数影响不显著。在地表季节性积水条件下,随着氮添加浓度上升,富集指数(EI)和成熟度指数(PPI)先下降后上升,但氮添加对土壤线虫群落香农威尔指数(H)和优势度指数(λ)无显著影响,20 kg·hm-2·a-1氮添加会促进干旱区高寒湿地土壤有机质分解途径由细菌向真菌分解途径发展。土壤含水量、土壤电导率和碱解氮是影响土壤线虫群落结构的主要因素。研究表明,氮沉降增加会影响土壤线虫群落中不同营养类群的丰度,但对土壤线虫群落结构多样性和干旱区高寒湿地土壤生态系统稳定性影响较小。 相似文献
92.
Ernesto San-Blas Gabriel Paba Néstor Cubillán Edgar Portillo Ana M. Casassa-Padrón César González-González Mayamarú Guerra 《Plant pathology》2020,69(8):1589-1600
Plant parasitic nematodes are generally soilborne pathogens that attack plants and cause economic losses in many crops. The infested plants show nonspecific symptoms or, often, are symptomless; therefore, diagnosis is performed by taking soil and root tissue samples. Here, we show that a combination of different infrared spectra analysis and machine learning algorithms can be used to detect plant parasitic nematode infestations before symptoms become visible, using leaves instead of roots and soil as samples. We found that tomato and guava plants infested with Meloidogyne enterorlobii produced different spectral patterns compared to uninfested plants. Using partial spectra from 1,450 to 900/cm as the "fingerprint region", principal component analyses indicated that after 5 (tomatoes) or 8 weeks (guava), plants with no visible symptoms of infestations were positively diagnosed. To improve the early detection response, we used machine learning modelling. A support vector machine (SVM) was used to obtain more robust, accurate models. The SVM model contained 34 support vectors, 17 for each level. The overall performance of the model was >97% and the total accuracy was significantly higher, demonstrating the absence of chance prediction. The best prediction of infestation was obtained at the second and fourth weeks for tomatoes and guavas, respectively, reducing the diagnostic time by half. The combined application of these techniques reduces the processing time from field to laboratory and shows enormous advantages by avoiding root and soil sampling. 相似文献
93.
南方根结线虫是一种严重危害我国蔬菜安全生产的土传病害,生产上亟需一种有效的防控方法。本研究从根结线虫卵囊中分离到一株生防真菌NF-06,通过形态学和分子生物学方法将其鉴定为粉红螺旋聚孢霉Clonostachys rosea。通过离体活性测定的方法测定NF-06发酵滤液对根结线虫2龄幼虫的致死作用,发现24、48和72 h后2龄幼虫的相对死亡率分别达63.6%,75.5%和87.0%。以产孢量为指标,优化菌株NF-06固体发酵条件,确定最佳基础培养基为麦麸和麦秸秆混合物,其比例为4:1(wt/wt),在基础培养基中添加10%玉米粉、2%蚕豆粉和0.05% KH2PO4可获得最大产孢量;最优培养条件为初始pH值7.0,初始含水量40%,接种量5%,产孢量达8.9×1010 CFU/g。室内盆栽防治效果测定显示,菌株NF-06固体发酵物能够有效降低土壤中的线虫数量和番茄根结指数,其中5 g/株穴施处理的线虫减退率和防治效果分别达67.9%和69.6%。本研究为生物杀线虫剂的开发和利用提供理论依据。 相似文献
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97.
‘99昆明世博会参展植物寄生线虫的检疫初报 总被引:1,自引:0,他引:1
本次博览会参展植物种类多,来源广,带土普遍疫情复杂。在严处国内外的参展植物中截获矛线目和垫刃目的13个科的56个属,其中在参展植物中截获我国对外检疫潜在危险性线。 相似文献
98.
Larval pigmentation, survival and growth of Penaeus indicus fed the nematode Panagrellus redivivus enriched with astaxanthin and various lipids 总被引:1,自引:0,他引:1
The highly unsaturated fatty acid (HUFA) content of the free-living nematode Panagrellus redivivus was successfully increased when three different lipid sources (cod-liver oil, marilla oil and capelin oil) from marine animals were used in the nematode culture medium. The lipid enrichment significantly increased the ω3 HUFA content, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), of the nematodes compared with lipid non-enriched nematodes. Penaeus indicus larvae fed the lipid-enriched nematodes had significantly ( P < 0.05) greater larval survival (69–77%) until metamorphosis than those fed non-enriched nematodes (54%).
This nematode species was also enriched with astaxanthin to determine the effects of this carotenoid on pigmentation, survival and growth during the larval development of P. indicus . The pigment, delivered via nematodes, significantly ( P < 0.05) improved larval coloration and survival (88%) compared with that of placebo-pigmented nematodes (78%). However, there was no strong evidence to show the benefit of either pigment and/or lipid enrichment on larval growth and development of P. indicus .
This study has shown that the nutritional value of the nematodes can be enhanced by the addition of fish oil into the culture medium. Supplementation of EPA and DHA, together with synthetic astaxanthin, allow the nematodes to be used as a sole diet for the larval culture of P. indicus . 相似文献
This nematode species was also enriched with astaxanthin to determine the effects of this carotenoid on pigmentation, survival and growth during the larval development of P. indicus . The pigment, delivered via nematodes, significantly ( P < 0.05) improved larval coloration and survival (88%) compared with that of placebo-pigmented nematodes (78%). However, there was no strong evidence to show the benefit of either pigment and/or lipid enrichment on larval growth and development of P. indicus .
This study has shown that the nutritional value of the nematodes can be enhanced by the addition of fish oil into the culture medium. Supplementation of EPA and DHA, together with synthetic astaxanthin, allow the nematodes to be used as a sole diet for the larval culture of P. indicus . 相似文献
99.
为确定越冬凡纳滨对虾亲虾黑鳃病症病因,对患病亲虾病因进行分析。结果显示,越冬后患病亲虾鳃部观察到大量线虫。虫体特征显微结构显示,雌、雄性线虫的平均体长分别为(983.6±16.69)μm和(956.9±12.14)μm,虫体表皮不均质,具有2纵列侧分化、4根头刚毛、3个口腔实齿、5个杯形肛前附器,化感器横向扁椭圆形,食道不形成食道球;经鉴定,确定该线虫隶属于色矛科(Chromadoridae)、色矛属(Chromadorella)。组织病理观察结果表明,线虫感染后亲虾鳃组织坏死、溶解,黑色素沉积,游泳足基部出现黑化层。本文报道了一种由色矛线虫引起的越冬亲虾黑鳃病症。 相似文献
100.
Dimitrios G Karpouzas Ioannis O Giannakou Allan Walker Simon R Gowen 《Pest management science》1999,55(11):1089-1094
Soils were collected from a potato-growing area in Serres, Northern Greece, where the nematicide ethoprophos was reported to have lost its effectiveness against cyst nematodes following 30 years of regular use. Incubation studies with ethoprophos and two bioassays using root-knot nematodes demonstrated that, in this heavily treated soil, the nematicide was degraded rapidly and nematicidal activity persisted only up to 14 days. In soil from an adjacent field with no known history of nematicide use during the preceding 14 years, ethoprophos was degraded more slowly and retained its nematicidal activity for more than 35 days. Ethoprophos efficacy was extended when the soil that had been treated in the field was autoclaved, although the effect was only transitory. The addition of ‘pre-conditioned’ soil from the previously treated field to samples of soil from the previously untreated field resulted in a significant acceleration of ethoprophos degradation compared with that observed in unamended soil from the previously untreated field. © 1999 Society of Chemical Industry 相似文献