【作者】 罗红燕；

【导师】 方德华；

【作者基本信息】 西南农业大学 ， 微生物学， 2002， 硕士

【摘要】 烤烟VA菌根具有活化土壤P、Zn养分、增强烟株抗逆性、促进烟株生长、提高烟叶品质等作用，长期以来一直是烤烟科研的热点。但目前有关VA菌根真菌感染烤烟后，对根际微生物数量和生物量的动态变化鲜有报道，而对这一问题的探讨，将有利于进一步阐明vA菌根真菌对改善土壤微生态环境、促进烤烟对矿物质养分吸收的机理。本试验在盆钵中装入适量红壤(pH5.6)，移栽NC—82烟苗，分别接和两种不同的VA菌根真菌G.M、G.V茵剂，以不接种作为对照，进行盆栽试验，按常规管理，移栽后生育期共106天。结果表明，两种不同的VA菌根真菌均能侵染烤烟根系形成VA菌根，对烤烟生长均具有明显的促进作用；对烤烟根际微生物的数量、组成及生物量的变化也具有显著影响。初步结论如下： 1 菌根形成能促进烤烟生长 接种G.M和G.V处理分别比对照提前3天和2天进入团棵期，提前11天和9天进入旺长期，分别比对照提前10天和8天进入成熟期。接种G.M、G.V菌根真菌处理比对照平均全磷、全钾、全氮利用率分别提高30.6％、18.3％、10.2％和22.5％、13.9％、4.8％；烟叶总糖含量明显提高(P＜0.05)；成熟初期，接种G.M、G.V处理的单株单叶干重、根系干重比对照分别增加35.42％、39.49％和22.01％、18.27％。 2 不同VA菌根真菌和烤烟形成的菌根所产生的根际效应有所不同 本试验所采用的两种VA菌根真菌，G.M对烤烟的最大侵染率88.3％，高于G.V对烤烟81.7％的侵染率。G.M与烤烟形成的菌根所产生的根际效应较G.V明显。接种G.M菌的烟株平均单株单叶干重、单株根系干重分别比接种G.V菌的烟株提高11.02％和17.95％；接种G.M菌的烟株平均全磷、全钾、全氮、总糖含量分别比接种G.V菌的增加6.7％、4.3％、4.5％、5.58％。对根际微生物数量和生物量的影响C.M较G.V明显。 3 菌根的形成对烤烟根际土壤微生物数量和生物量影响十分明显 在烤烟生长前期，菌根际土壤微生物数量较对照有所下降，而在烤烟生长中后期，菌根际土壤微生物数量较对照明显增加。其变化规律是：当烟株进入缓苗后期和团棵末期时，菌根际细菌数量低于对照，表明菌根形成初期，对根际细菌的增殖具有一定的抑制作用： 当烟株进入旺长中期和成熟初期时，菌根际细菌数量均高于对照(P＜0.01)，说明菌根形成中后期，促进了根际细菌的增殖。放线菌和好气性纤维素分解菌、氨化细菌、自生固氮菌也有类似的变化规律。菌根际的真菌数量一直低于对照，接种与对照间的真菌数量差异在成熟初期达显著水平(P＜0.05)。整个生育期内菌根际的微生物生物量始终高于对照，接种G.M、G.V菌根真菌处理在烟株缓苗后期、团棵末期、旺长中期，根际的微生物生物量分别较对照增加74.38％、167.13％、 — —————209．63％和51．％％、134．27％、176．47％，与微生物数量变化不一致。 4菌根的形成促进了根际土壤微生物的代谢，改善了土壤微生态环境 烤烟VA菌根形成中后期，细菌、放线菌等微生物种群数量和微生物生物量，好气性纤维素分厢、氨化细菌、自生固氮菌等微生物生理群数量，均显著超过对照非菌根际；接种GAI、G．V菌根真菌处理烤烟根际土壤中有效氮、有效磷、有效钾及有机质含量比对照分别提高25．49％、15．71％、ZI刀1罚、16．5％和I3．刀％、14．47％、1481％、13．4呢，由此说明，佩菌根形成的中后期使烤烟根际微生物的代谢进程和繁殖速度加快，有利于土壤养分的积累，进而改善了烤烟根际土壤微生态环境。更多还原

【Abstract】 The present experiment studied the effect of VAM fungus on the growth of Flue-cured tobacco and micro-ecological environment of Flue-cured tobacco rhizosphere. Tape of NC-82 Flue-cured tobaccos in sterilized red soil (pH5.6) was inoculated with two strains of Glomus mosseae and Glomus versiforme .Research was focused on the total number of microbial population .physiological group of microbianism and Microbial biomass .Following are the main results:1 After Flue-cured tobaccos forming mycorrhiza with G.M and G.V , It promoted the drought resistance and increased the products of Flue-cured tobaccos. Compared with the control ,They decreased the growth time by 11 and 8 days; The contents of P,K,N in tobacco leaves were increased by 30.6% > 18.3 %^ 10.2%, 22.5 %^ 13.9%, 4.8% individually; The dry weight of single tobacco leaf (g/plant) and root (g/plant) were increased by 35.42 % ?39.49 %, 22.01 % ^ 18.27 % respectively. The total sugar content of the leaf was also remarkablely improved (p<0.05).2 The results showed that 2 VAM fungi tested had a good symbiotic relationship with roots of Flue-cured tobacco.The incidences of infection were both over 80%.However,there were significant differences in the effectiveness between the 2 VAM fungi. Glomus mosseae was more efficient than Glomus versiforme. The P,K,N and the total sugar and in tobacco leaves were increased by 6.7 % ^ 4. 3 % ^ 4. 5 % N 5. 53 %. The dry weight of single tobacco leaf (g/plant) and root (g/plant) were increased by 11. 02 % > 17.95%.3 In flue-cured tobacco rhizosphere.the infection of 2 VAM fungus induced thegreater change of microbial population and biomass. At the first sampling, the total number of bacteria in the inoculation treatment condition were slightly less than that in control condition, but the difference was unstriking(P>0.05); At the second sampling,the total number of bacteria hi the inoculation treatmenr condition were much less than that of control condition (P<0.05). At the later two sampling times, the total number of bacteria in the control condition were extremely more than that of the noninoculation treatment (P<Q.01).It showed the growths of that bacteria were inhibited in the second measuring.Then, there were conditions that could promote bacteria growth. The total number of actinomycetes> Aerobic-Cellulose decomplosing-bacterium > ammonifiers and N-fixer in root zone variated as that of bacteria. The total number of fungi were decreased slightly in the whole growing period of Flue-cured tobaccos, and extremely less than that of the noninoculation treatment ( P<0. 05 ) during the last measuring. Biomass was increased in the whole growing period of Flue-cured tobaccos.4 After Flue-cured tobaccos forming mycorrhiza with G. M and G. V, It improved the micro-ecological environment in the soil of Flue-cured tobaccos rhizosphere.The content of available N(mg/kg) ,available P(mg/kg) , available K(mg/kg) and O.M (g/kg) increased 25. 49%, 15.71%, 21.01%, 16.5%, 13.72%, 14.47%, 14.81%, 13.4% respectively. The productivity of soil were promoted effectively for the accumulated of the soil nutrient content更多还原