丛枝菌根真菌对还田稻秆分解的影响

Effects of Arbuscular mycorrhizal Colonization on Rice-straw Decomposition

【目的】研究接种丛枝菌根(Arbuscular mycorrhizal,AM)真菌对水稻秸秆分解的作用及影响机理。【方法】稻秆还田采用室内盆栽法,通过接种摩西球囊霉Glomus mosseae、根内球囊霉Glomus intraradices和幼套球囊霉Glomus etunicatum,研究了3种AM真菌对宿主小麦根系侵染率、稻秆分解速率、土壤酶活性和土壤微生物量的影响。【结果】3种AM真菌均能较好的与小麦根系形成共生系统,侵染率均达84%以上。接种G.mosseae和G.intraradice处理显著促进了稻秆的分解率(增幅分别为26.51%和16.27%);各接菌处理下的土壤微生物量和与碳氮磷元素矿化相关的纤维素酶、蛋白酶、硝酸还原酶、酸性磷酸酶以及碱性磷酸酶均表现出上升趋势,其中G.mosseae对土壤微生物量和各种酶活性的促进作用最显著。【结论】接种AM真菌能够促进还田稻秆的分解,正向调节农田土壤生态系统中有机质的养分释放。摩西球囊霉菌对稻秆分解的促进作用优于其他2种菌根真菌。因此在后续的稻秆分解应用试验中使用G.mosseae作为优势菌种之一进行研究是可行的。

【Objective】The present study aimed at understanding the effects and mechanism of Arbuscular mycorrhizal(AM)fungi colonization on the decomposition of rice straw.【Method】Infection rate of wheat root system,straw decomposition rate,soil microbial biomass and soil enzyme activities were conducted after three AM fungi(Glomus mosseae,Glomus intraradices and Glomus etunicatum)colonization in a seven-month pot experiment of wheat.【Result】All the AM fungi could form symbiotic systems with wheat roots,and the infection rate was over 84%.The inoculation of G.mosseae and G.intraradice significantly promoted the decomposition rate of rice straw(26.51%and 16.27%,respectively).Soil microbial biomass and the enzyme activities involved in soil carbon,nitrogen and phosphorus mineralization(cellulase,protease,nitrate reductase,acid phosphatase and alkaline phosphatase)all showed upward trends,of which G.mosseae got the most significant effect.【Conclusion】Inoculation with AM fungi can promote the decomposition of rice straw and regulate the release of organic matter in farmland soil ecosystem.The positive effect of G.mosseae fungus on the decomposition of rice straw is better than that of the other two AM fungi.It is feasible to use G.mosseae as one of the dominant strains in the subsequent application test of rice straw decomposition.