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为了进一步认识辽东栎(Quercus liaotungensis)与油松(Pinus tabulaeformis)在黄土高原森林植被演替中的竞争关系,利用“平板培养法及MPN法”测定了辽东栎与油松根际土壤微生物组成,用“熏蒸提取-容量分析法”测定了土壤微生物生物量碳(MBC)。结果显示,辽东栎与油松根际土壤微生物三大类群总数量,根面高于根区。细菌数量在根面为辽东栎高于油松,但在根区无显著差异,放线菌、真菌、氨化细菌和固氮菌数量在根面与根区均为辽东栎高于油松,硝化细菌数量在根面与根区均无显著差异。辽东栎根区土壤MBC含量高于油松。以上结果表明,根系分泌物浓度及种类对根际土壤微生物组成影响较大;辽东栎丰富的根际土壤微生物组成有益于其对土壤养分的转化、吸收与利用,并在与油松的竞争过程中处于优势地位。
In order to further understand the competition between Quercus liaotungensis and Pinus tabulaeformis in the succession of forest vegetation in the Loess Plateau, the rhizosphere soil micro-organism composition of Quercus liaotungensis and Pinus tabulaeformis was determined by using “plate culture method and MPN method” The soil microbial biomass carbon (MBC) was determined by “fumigation extraction - volumetric analysis”. The results showed that the total number of rhizosphere soil microbial populations in Quercus liaotungensis and Pinus tabulaeformis and the root surface were higher than those in the root zone. The number of bacteria in the root surface of Quercus liaotungensis was higher than that of Pinus tabulaeformis, but there was no significant difference in the root zone. The numbers of actinomycetes, fungi, ammoniated bacteria and nitrogen-fixing bacteria were higher in Pinus tabulaeformis and Pinus tabulaeformis than in Pinus tabulaeformis and Nitraria The number of bacteria in the root and root zone were no significant differences. The content of MBC in the soil of the oak was higher than that of Pinus tabulaeformis. The above results showed that the concentration and species of root exudates had a significant effect on the rhizosphere soil microbial composition. The rhizosphere soil microbial composition of Quercus liaotungensis was beneficial to the conversion, absorption and utilization of soil nutrients and the competition process with Pinus tabulaeformis In a dominant position.