大豆种质资源对大豆孢囊线虫4号生理小种的抗性鉴定研究

本研究旨在鉴定和评价大豆种质资源对大豆孢囊线虫4号生理小种的抗性.1988-1990年在砀山县病地里对黄淮地区1800份大豆种质资源进行了抗大豆孢囊线虫4号生理小种鉴定.结果鉴定出7个抗病品种,其中2个褐色种皮,5个黑色种皮.品种的抗性与花色、茸毛色关系密切,与株高、生育期和百粒重不相关.     

8种检疫线虫传入黑龙江的风险评估

根据国际植物保护公约(InternationalPlantProtectionConvention,IPPC)的国际植物检疫措施标准11(InternationalStandardforPhytosanitaryMeasures11,2001,ISPM11)并参考欧洲和地中海植物保护组织(EuropeanandMediterraneanPlantProtectionOrganization,EPPO)有害生物风险分析风险评估指导标准(EPPOStandardPM5/3GuidelinesonPestRiskAnalysis—PestRiskAssessmentScheme),对马铃薯金线虫、马铃薯白线虫、相似穿孔线虫、鳞球茎茎线虫、甜菜胞囊线虫、水稻茎线虫、椰子红环腐线虫和松材线虫这8种检疫性线虫传入黑龙江省进行风险评估。风险评估表明,相似穿孔线虫传入黑龙江省具有高度风险,马铃薯金线虫、马铃薯白线虫、鳞球茎茎线虫、甜菜胞囊线虫、和松材线虫传入黑龙江省具有较高风险,水稻茎线虫风险较低、椰子红环腐线虫无风险。应该加强对风险较高的几种线虫的风险管理。     

蚓粪和益生菌配施对设施番茄地土壤线虫群落的影响

为探究蚓粪和益生菌互作对大棚番茄地土壤线虫数量和群落结构的影响,设置CF(单施化肥)、CF+BM(化肥配施巨大芽孢杆菌)、CF+BA(化肥配施解淀粉芽孢杆菌)、VC(单施蚓粪)、VC+BM(蚓粪配施巨大芽孢杆菌)和VC+BA(蚓粪配施解淀粉芽孢杆菌)6个处理。结果表明:与单施化肥相比,单施蚓粪有助于土壤线虫数量的提高,而蚓粪配施益生菌相比单施蚓粪对线虫数量的提高更加显著;化肥配施益生菌在盛花期时对土壤线虫数量提高不显著,收获期时有显著提高但效果不及蚓粪配施益生菌。单施化肥或蚓粪提高了植食性线虫短体属(Pratylenchus)的相对丰度,且单施蚓粪提高幅度显著高于单施化肥。与单施化肥相比,单施蚓粪显著降低了食细菌线虫比例,而化肥配施益生菌显著降低了食细菌线虫和植食性线虫比例,增加了食真菌线虫比例。蚓粪配施益生菌相比单施蚓粪显著增加了食细菌和食真菌线虫比例,降低了植食性和捕杂食性线虫比例。与单施化肥或蚓粪相比,蚓粪配施益生菌对瓦斯乐斯卡指数(WI)、食真菌线虫与食细菌线虫比率(F/B)和植食性线虫成熟指数(PPI)均能够产生积极影响,且效果优于化肥配施益生菌。综合比较可以发现,与单施化肥或蚓粪相比,蚓粪配施益生菌能够减缓植食性线虫增长,土壤环境和线虫群落趋于健康和稳定,是值得推荐的施肥方式。     

旱地红壤线虫群落对不同耕作年限的响应及指示意义

我国热带和亚热带地区的红壤农田肥力水平低,严重制约着农业生产力的提升。不同农业管理措施会对土壤理化性质和生物群落产生不同的影响。本文研究了不同耕作年限条件下的旱地土壤,选取耕作10 a、20 a、50 a的花生地和菜地,并以未开垦的原始荒地作为对照。结果显示,与荒地相比,各年限花生地的土壤肥力等指标表现出下降的趋势,菜地土壤的各项性质则呈现提升的趋势。耕作20 a的花生地土壤有机碳、全氮、微生物生物量碳、有效磷等指标均最低,同时耕作50 a的菜地各项性质相对于10 a有显著的提升(p0.05)。花生地中植食性线虫比例伴随耕作年限延长而下降,而菜地中食细菌线虫比例伴随耕作年限延长而逐渐上升。从线虫生态指标数据显示,花生地相对于频繁施肥和耕作的菜地表现出更为稳定的土壤食物网。因此,线虫群落对不同耕作年限下旱地红壤生态系统的变化表现出一定的指示潜力。     

长期施肥对哈尔滨黑土土壤线虫群落的影响

土壤线虫作为土壤生态系统中重要的组成部分,在养分转化及物质循环中起着重要作用。为研究长期施肥对土壤线虫群落的影响,在农业部哈尔滨黑土生态环境重点野外科学观测试验站进行了长期施用有机肥、氮肥、磷肥、钾肥及不施肥处理的田间试验。结果表明:长期施肥对土壤线虫群落组成及线虫群落中不同营养类群的相对丰度均产生一定的影响。长期施肥条件下,土壤线虫种群的种类数量呈下降的趋势,除单施氮肥处理外,其余施肥处理土壤食细菌线虫的相对丰度均显著高于不施肥处理,而植物寄生线虫相对丰度则显著低于不施肥处理;从土壤线虫生态指数看,施肥处理自由生活线虫成熟度指数(MI)均低于对照,而施用有机肥及磷肥处理的土壤WI值显著高于不施肥对照;土壤线虫群落的变化表明土壤线虫群落对施肥产生了响应,可以用作施肥对土壤质量变化影响的生物学指标。     

The distribution of nematodes and soil microbial communities across soil aggregate fractions and farm management systems

We hypothesized that nematode and microbial communities vary between soil aggregate fractions due to variations in physical and/or resource constraints associated with each fraction and that this, in turn, contributes to management impacts on whole soil food webs. Nematode and microbial communities were examined within three soil fractions: large macroaggregates (LM; >1000 μm), small macroaggregates (SM; 250-1000 μm) and inter-aggregate soil and space (IS; <250 μm) isolated from soils of four agricultural management systems: conventional tomato (CON), organic tomato (ORG), a minimum till grain-legume intercrop with continuous cover (CC) and an unmanaged riparian corridor (RC). Aggregate fractions appeared to influence nematode assemblages more than did management system. In general the IS and LM fractions contained higher densities of all nematode trophic groups than did SM. Management × fraction interactions for bacterivores and fungivores, however; suggested a non uniform trend across management systems. The IS fraction exhibited stronger trophic links, per the nematode structure index (SI), while the LM and SM fractions had more active fungal decomposition channels as indicated by the channel index (CI). Higher adult to juvenile ratios in the LM and IS than the SM fraction, and a positive correlation between nematode density in the IS fraction and the proportion of macroaggregates in the soil, indicated an association between soil structure and nematode distribution. Microbial communities varied across both aggregate fractions and management systems. Phospholipid fatty acid (PLFA) analysis suggested that the LM fraction contained greater microbial biomass, gram positive bacteria, and eukaryotes than the IS fraction, while SM contained intermediate PLFA associated with these groups. Total PLFA was greater under RC and ORG than under CC or CON. Total PLFA was positively correlated with % C in soil fractions while nematode abundance exhibited no such relationship. Our findings suggest that microbial communities are more limited by resource availability than by habitable pore space or predation, while nematode communities, although clearly resource-dependent, are better associated with habitable pore space for the soil fractions studied here.     

藏北高寒草甸土壤线虫群落对围封及自由放牧的响应

为了解放牧干扰对藏北高寒草甸的影响,以及连续围封措施对草地的恢复作用,2013—2015年连续3年对那曲县围封、自由放牧天然高寒草甸土壤线虫群落进行取样调查及数据分析。结果表明:围封、放牧样地的线虫个体数量在年际间的变化均较明显,植食性线虫是整个线虫群落个体数量变化的主要贡献者;围封样地的线虫个体密度、多样性指数H′、丰富度指数SR,以及优势度指数λ的年际变化幅度均大于放牧样地;食细菌性线虫个体数量及线虫通路比值(NCR)表明放牧样地的有机质转化效率高于围封样地;成熟度指数(MI)、植物寄生线虫指数(PPI)分析表明,所研究区域经5年围封,高寒草甸生态系统稳定性没有明显的提高,相反,现有放牧强度维持或者增加了线虫群落的物种多样性,利于物种共存和草地生态系统稳定性的维持。     

Interplay of omnivory, energy channels and C availability in a microbial-based soil food web

 To study the effects of omnivory on the structure and function of soil food webs and on the control of trophic-level biomasses in soil, two food webs were established in microcosms. The first one contained fungi, bacteria, a fungivorous nematode (Aphelenchoides saprophilus) and a bacterivorous nematode (Caenorhabditis elegans), and the second one fungi, bacteria, the fungivore and an omnivorous nematode (Mesodiplogaster sp.) feeding on both bacteria and the fungivore. Half of the replicates of each food web received additional glucose. The microcosms were sampled destructively at 5, 9, 13 and 19 weeks to estimate the biomass of microbes and nematodes and the soil NH₄ ⁺-N concentration. The evolution of CO₂ was measured to assess microbial respiration. Microbial respiration was increased and soil NH₄ ⁺-N concentration decreased by the addition of glucose, whereas neither was affected by the food-web structure. Supplementary energy increased the biomass of fungi and the fungivore, but decreased the biomass of bacteria, the bacterivore and the omnivore. The omnivore achieved greater biomass than the bacterivore and reduced the bacterial biomass less than the bacterivore. The biomass of the fungivore was smaller in the presence of the omnivore than in the presence of the bacterivore at three sampling occasions. Fungal biomass was not affected by food-web structure. The results show that the effects of the omnivore were restricted to its resources, whereas more remote organisms and soil processes were not substantially influenced. The results also indicate that the presence of an omnivore does not necessarily alter the control of populations as compared with a food web containing distinct trophic levels, and that the fungal and bacterial channels may respond differently to changes in energy supply. Received: 15 December 1997     

2种大豆胞囊线虫鉴定方法比较及分析

从计数方法、播种方法、鉴定准确性等方面对实用性较强的塑料钵柱法和酸性品红染色法2种大豆胞囊线虫鉴定方法进行了比较。塑料钵柱法鉴定时,可观察到大豆胞囊线虫病的主要发病特征,包括叶片变黄﹑植株矮小﹑根部有胞囊形成等典型症状。利用酸性品红染色法鉴定时未见叶片变黄,根部未见胞囊,但在20×显微镜下可检测处于二龄期的幼虫,可用于鉴定计数。2种鉴定方法对鉴别寄主具有同等区别抗感材料的能力,但在鉴别较大群体时品红染色法鉴定结果变异率低,同时在鉴定周期和效率上明显优于塑料钵柱法。因此,在对较大群体进行鉴定时,酸性品红染色法是一种便捷且准确性较高的鉴定方法。     

一对姊妹线虫的杂交试验研究

基于李氏长尾线虫(Seinura liiHuang & Ye,2006)与吴氏长尾线虫(S.wuaeHuang & Ye,2006)是一对形态很相似的姊妹线虫,在原始描述之后,采用单一配对杂交方法来进一步探讨它们相互间的生殖关系。结果表明,李氏长尾线虫与吴氏长尾线虫在生殖上相互隔离,并且它们之间的生物学特性可能存在着较大差异;研究还表明,李氏长尾线虫与吴氏长尾线虫的生殖方式都为有性生殖。