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丛枝菌根(AM)真菌的侵染势(Colonizationpotential,CP)和接种势(inoculumpotential,IP)是菌根学领域非常重要的两个概念。IP已定义为接种物中有活力的真菌繁殖体及结构的数量(Liu&Luo,1994)。而CP的定量描述和测定方法尚未建立。本文将CP定义为单位数量接种物在侵染初期侵染植物根系的能力,其定量测定公式为:CP=N×L/IP×T,其中N为单位根长侵入点数+根内和根外菌丝数+含有丛枝的细胞数+泡囊数;L为每株寄主植物根系总长度;IP为接种物的接种势单位数;T为接种后的天数。用棉花(Gossypiumhirsutum)、大豆(Glycinemax)、红三叶(Trifoliumpratense)和玉米(Zeamays)和3种AM真菌Gigasporamargarita(Gim),Glomusintraradices(Gi),andGlomusversiforme(Gv)不同剂量(100,300,900,2700and8100接种势单位)的接种物进行试验,以定量测定CP、以及CP和IP之间的关系。结果表明,在相同数量的IP条件下,不同AM真菌具有不同的CP,应用该研究建立的定量测定方法获得了CP与IP显著相关(p=0.01,r=0.9161~0.9393)的试验结果。CP可以作为评价接种物有效性和质量的指标。它说明了AM真菌侵染初始阶段的侵染能力,因此CP的测定应该在侵染率达到最高之前进行,对3种一年生植物进行的试验表明,最佳测定时间应在接种后4到6周。
Colonization potential (CP) and inoculum potential (IP) of arbuscular mycorrhizal (AM) fungi are two very important concepts in the field of mycorrhiza. IP has been defined as the number of viable fungal propagules and structures in inoculum (Liu & Luo, 1994). The CP quantitative description and determination method has not been established. In this paper, CP was defined as the ability of inocula to infect plant roots in the early stage of infection. The quantitative determination formula is: CP = N × L / IP × T, where N is the unit root length of invasion points + root and root Number of mycelium + number of cells containing clusters of branches + number of vesicles; L is the total root length of each host plant; IP is the number of inoculation potential units of the inoculum; and T is the number of days after inoculation. Gossypium hirsutum, Glycine max, Trifoliumpratense and Zeamays and three kinds of AM fungi Gigasporamargarita (Gim), Glomus intraradices (Gi), andGlomusversiforme (Gv) at different doses (100, 300, 900, 2700 and 8100 inoculation potential units ) Inocula to test quantitatively CP, as well as the relationship between CP and IP. The results showed that different AM fungi had different CP under the same amount of IP, and the results of the correlation between CP and IP (p = 0.01, r = 0.9161-0.9393) were obtained by using the quantitative assay established in this study. CP can be used as an indicator to assess the effectiveness and quality of inoculum. It demonstrates the ability of AM fungi to infect in the initial stages of infection, so the determination of CP should be performed prior to reaching the highest infection rate. Trials of three annuals show that the optimal assay time should be between 4 and 6 weeks after inoculation .