【作者】 陈国康；

【导师】 宇振荣； 曹志平；

【作者基本信息】 中国农业大学 ， 生态学， 2005， 博士

【摘要】 本研究基于中国-意大利环境合作项目青州试点2002～2003年开展的实验工作,重点对甲基溴替代技术条件下温室土壤生态系统的生物群落及食物网特征等加以分析和比较。文章围绕(1)土壤消毒措施对温室土壤理化性质、微生物、4种土栖真菌、螨类及弹尾目的扰动作用,(2)作为甲基溴替代技术之一的番茄抗性砧木SIS-1(Lycopersicon lycopersicum×Lhirsutum)在抗土传病害的同时对根围上述几项生物特征的影响,(3)温室土壤生态系统的食物网构成特征、两番茄品种间的食物网比较、面向有机体模型、食物网的时间变异及对土壤消毒措施的响应,等层面逐步阐述,目的在于探讨温室土壤生物群落及其构成的食物网对土壤消毒措施、番茄抗性砧木的响应机制。研究得主要结果如下: 同对照和太阳能+生防制剂处理相比,甲基溴和威百亩等4个化学处理对番茄根结线虫具有明显的控制效果(P<0.05)。包括太阳能+生防制剂处理的5个土壤消毒措施降低了土壤微生物、4种土栖真菌(镰刀菌、疫霉菌、腐霉菌和木霉菌)和螨类的数量水平,螨类群落物种数、多样性水平也明显降低(P<0.05)。螨类群落中的弱势类群对土壤消毒措施反应更为敏感,但从较长期的尺度看,消毒措施则明显降低了优势类群的数量,因而对螨类群落数量动态表现为“削峰”作用,并且提高了螨类群落的多样性水平。聚类分析也印证了土壤消毒对螨类群落的重要影响。该温室土壤弹尾目在番茄整个生长期维持相对稳定的数量水平,受消毒处理波及的影响较小。研究表明,甲基溴及其替代技术消毒措施对土壤化学性质有重要影响,它直接改变了土壤某些矿质营养的供给形式,从而间接影响了微生物及更高营养级的食微动物、捕食性动物的群落特征。 与感病的毛粉品种(Lycopersicum esculentum Mill)相比,番茄抗性砧木具有综合控制根结线虫病、立枯病、猝倒病及蕨叶病毒病的显著效果,有效降低了幼苗死亡率及收获期根结线虫的为害(P<0.05)。抗性砧木抑制了根围4种真菌的种群增长,降低了土壤螨类及弹尾目数量,也表现出同于消毒处理对螨类数量波动的“削峰”作用、对维持弹尾目种群的稳定性上。但与土壤消毒措施不同的是,抗性砧木作为一种生物处理防病措施,显著提高了螨类群落的多样性及均匀度水平(P<0.05),促使了群落结构随时间发生明显的更替,在番茄生长期时间尺度上促成了螨类群落构成的多样化及物种分布的均匀性。 划分生物营养类群并将其数量转换为生物量,有助于更清楚地其在食物网的功能和地位。该温室番茄根围食物网是以细菌为基础的食物网,微生物、原生动物占据了土壤食物网的绝大部分,是金字塔“塔基”,其次为螨类、线虫和弹尾目,组成了“塔尖”。土壤食物网是地下C循环的必须途径,面向生物有机体模型(也称食物网模型)的建立,帮助我们了解了土壤有机C经由食物网流动循环的途径和方向,认识了各营养级生物的地位和功能,该食物网模型既定性地赋予了其在食物网中的位置,又定量地给各功能成分赋值,直观地勾勒了各营养功能类群在土壤食物网中的分解、捕食作用。基于食细菌和基于食真菌的2条分解食物链路径构成了该温室土壤腐屑食物链,前者包括细菌、原生动物、食细菌线虫,后者包括真菌、食真菌线虫、食真菌螨类、食真菌弹尾目,且前者所含生物量碳明显高于后者。3类捕食关系组成了该温室土壤捕食食物链:其一,植物(番茄)活根-食植物线虫-捕食性线虫-捕食性螨类;其二,食真菌线虫-捕食性线虫-捕食性螨类;其三,食真菌螨类/食真菌弹尾目/捕食性线虫-捕食性螨类捕食。更多还原

【Abstract】 Based on Sino-Italian environmental cooperation project, the experiments were carried out in Qingzhou demonstrational site of Shandong province from 2002 to 2003. The purpose of study was to understand the characteristics of soil biota community and food web in soil ecosystem of greenhouse, and how they responded to the conditions of alternative technologies of methyl bromide in soil fumigation. Three parts were involved in the study. Firstly, how was the disturbance of soil disinfections practices to chemical characteristics, microorganisms, four fungi-Fusarium spp., Trichoderma spp., Phytophthora spp., Pythium spp., soil mites and collembolan? Secondly, how was effect of tomato resistant rootstock (Beaufort SIS-1, Lycopersicon lycopersicum x L.hirsutum) as one of promising alternative technologies of methyl bromide on the above biotic indicators? Thirdly, what was the structure of food web in greenhouse agro-ecosystem, how to construct Organisms-oriented model, how was temporal dynamics of food web and its response to soil disinfections practices and tomato resistant rootstock? The principal results are as follows.As compared to control and SS+BCA, Four disinfections practices such as methyl bromide (MB) and metham sodium (MS), significantly (P<0.05) repressed root-knot nematode disease {Meloidogyne spp.). Fives disinfections practices including SS+BCA, made abundance of soil microorganisms, four fungi, and mites decline, so did the biodiversity and species number of soil mites (P<0.05 ). The inferior species were more sensitive to soil disinfections practices. The abundance of dominant species in mite community, however, decreased after soil disinfections in relative long period, so as to cut the peak of mites dynamics occurring in control plot. Hierarchical Cluster Analysis of mite community dynamics proved the above results. The density of collembolan in the soil of greenhouse was kept in low level during the whole tomato growth, which indicted collembolan was weakly affected by soil disinfections. Evidence in the study showed methyl bromide and its alternatives technologies impacted soil chemical characteristics, possibly changed nutrients release directly, affected indirectly the characteristics of microorganisms and microvores even predators communities in soil ecosystem.As compared to susceptible cultivar Maofen (Lycopersicum esculentum Mill), tomato resistant rootstock significantly controlled plant diseases such as Meloidogyne spp., Rhizoctonia solani, abrupt damping off, ToMV, as a result significantly declined the dead rate of seedlings, the disease index of root-knot nematode (P<0.05) . Furthermore, Beaufort SIS-1 repressed the population increase of four fungi, decreased the densities of mites and collembolan, cut the peak of mites dynamics occurring in Maofen plot, kept the stability of collembolan community. The difference between Beaufort SIS-1 and soil disinfections was that tomato resistant rootstock significantly enhanced the biodiversity level and evenness index (P<0.05 ) because it promoted the change of community structure and distribution of species of soil mites with the time going on.Conversion of abundance of soil biota into biomass carbon after functional groups classification based on the feeding habits was proved much necessary to know the position and function of functional groups in food web. Bacteria-based food web was found predominant in the soil ecosystem of greenhouse, with a high percent of soil microbiomass and protozoa biomass as the bottom of Pyramid,while the biomass of soil mite, nematodes and collembolan as the top of Pyramid. Food web is the channel of organic carbon cycle below ground. The establishment of Organisms-oriented model (Food web model) contributed to make us know the way of organic carbon cycle below ground, and the position and function of functional groups in food web were understood qualitatively and quantitatively. Detritus food chains involved bacteria-based food chain and fungi-based food chain; the former containing more biomass carbon than the later inc更多还原