内生真菌与苍术粉对连作花生根际微生物区系和微量元素的影响

通过盆栽试验,研究了内生真菌拟茎点霉B3(Phomopsis liquidambari)及苍术(Atractylodes lancea)粉联合施用对连作花生根际土壤微生物区系、酶活性及有效态微量元素(Mo、B、DTPA-Fe、Zn、Cu、Mn)含量的影响。结果表明:内生真菌B3和苍术粉复合处理比内生真菌B3处理的荚果和秸秆产量分别增加10.28%和14.11%,内生真菌B3处理与正常施肥相比显著提高了根瘤数量、荚果和秸秆产重,各处理组与正常施肥对照相比分枝数和根长无显著差异。B3处理与对照相比显著提高了种子期、结荚期和成熟期根际土壤可培养细菌和放线菌数量,B3和苍术粉复合处理与对照相比显著提高种子期、花期和成熟期可培养真菌和放线菌数量;细菌DGGE指纹图谱聚类分析表明,B3和苍术粉复合处理相对于正常施肥处理,显著改变种子期、苗期、花期和成熟期花生根际土壤细菌群落结构,同时苗期、花期和结荚期的细菌条带数和香农指数也有所提高,真菌DGGE指纹图谱聚类分析表明,B3和苍术粉复合处理对真菌群落影响较大,除种子期以外的生育期真菌条带数和香农指数都有明显提高,花期真菌群落结构变化最大,相似度仅为49.6%。花生关键生育期(花期和结荚期)根际土壤脲酶和蔗糖酶活性B3处理和复合处理都显著高于正常施肥对照,促进了连作花生生态系统的物质循环和能量流动。B3和苍术粉复合处理促进了花生生长发育必需微量元素Mo、B、Fe、Zn、Mn的活化,花生叶片和籽粒中微量元素Mo、B、Fe的积累显著增加。研究结果表明,内生真菌和苍术粉联合施用能有效改善连作花生根际微生物区系,提高土壤酶活性,促进微量元素的活化和吸收,对缓解花生连作障碍具有重要意义。

Effects of endophytic fungi and Atractylodes lancea powder on rhizosphere microflora and trace elements during continuous peanut cropping

A pot experiment was conducted to study the effects of the endophytic fungi Phomopsis liquidambari strain B3 and Atractylodes lancea powder on rhizosphere soil microflora, enzyme activity, and available trace elements under continuous peanut cropping. The results showed that strain B3 and A. lancea powder significantly increased peanut straw and pod yield by 14.11% and 10.28%, respectively, relative to B3 treatment alone. B3 treatment significantly increased peanut root nodules as well as straw and pod yield relative to the control, which was grown under conventional fertilizer treatment. There were no significant differences in peanut root length and branch numbers between the treatments and the control. In addition, the B3 treatment resulted in significantly more culturable bacteria and actinomycetes in peanut rhizosphere soil at seed, podding, and mature growth stages than did the control. The B3 and A. lancea powder treatment resulted in a significantly larger population of culturable fungi and actinomycetes at seed, flowering, and mature growth stages than the control. 16S rDNA PCR-DGGE analysis showed that the B3 and A. lancea powder treatment significantly changed the soil bacteria community structure at seed, seedling, flowering, and mature growth stages and increased bacterial diversity during the seedling, flowering, and podding growth periods compared with the control, as estimated by the Shannon and band number indices. The B3 and A. lancea powder and B3 treatments markedly increased the activities of soil urease and sucrase during the flowering and podding growth periods, which promote material cycle and energy flow in the monoculture peanut ecosystem. It is worth noting that B3 andA. lancea powder activated essential trance elements (Mo, B, Fe, Zn, and Mn) in peanut rhizosphere soil at various growth stages and dramatically promoted absorption of Mo, B, and Fe in peanut leaves and kernels, particularly Mo and Fe. The results of this study suggested that the combined application of endophytic fungi and A. lancea powder could effectively improve the continuous peanut cropping soil microflora, promote enzyme activity, and increase the absorption of important trace minerals. These effects are important for minimizing or even eliminating obstacles associated with continuous peanut cropping.