三种不同土壤改良剂对黄瓜根际微生物数量和群落代谢功能多样性的影响

Effects of three different soil amendments on the number and metabolic function diversity of rhizospheric microorganisms of cucumber

摘要:

【背景】土壤微生物在调节植物生长、提高土壤养分利用率及维持生态系统稳定性等方面发挥着重要作用。【目的】探讨蚯蚓原位处理废弃物及脱硫石膏改良土壤后的微生物群落结构多样性特征，深入研究黄瓜根际微生物群落数量与微生物指数之间的相关性。【方法】通过平板培养法测定可培养真菌、细菌、放线菌群落数量与Biolog-ECO微平板法分析OD₅₉₀值微生物碳源利用率相结合，研究蚯蚓处理废弃物原位生成蚯蚓粪替代土壤(T1)、脱硫石膏(3 t/hm²)(T2)、蚯蚓处理废弃物原位生成蚯蚓粪与脱硫石膏混施(T3)这3种土壤处理下栽培黄瓜，其根际微生物群落多样性特征。【结果】T1、T3处理的可培养放线菌数量显著高于CK、T2；细菌与真菌菌落数量无显著性差异。各处理的平均每孔颜色变化率(average well color development，AWCD)呈“厂”型趋势变化，在0−96 h上升迅速，96−144 h缓慢上升至最高值，T1、T3处理的AWCD值高于CK、T2。与对照相比，各处理的AWCD值、Shannon指数、Simpson指数、Pielou指数和McIntosh指数存在显著性差异。与CK相比，T1与T2处理的碳源利用率较高。细菌、放线菌数量与AWCD值、Shannon指数、Simpson指数、McIntosh指数和Pielou指数呈显著性正相关(p<0.05或p<0.01)，而真菌可培养数量与AWCD值、Shannon指数、Simpson指数、McIntosh指数和Pielou指数呈显著性负相关(p<0.05或p<0.01)。【结论】蚯蚓原位处理废弃物种养模式下，土壤可培养微生物总菌群落较多，群落多样性指数较高，微生物碳源利用率较高，探究蚯蚓处理废弃物的生态功能特征变化，以期为新型栽培模式提供理论依据。

Abstract:

[Background] Soil microbes play an important role in regulating plant growth, improving soil nutrient utilization rate and maintaining ecosystem stability. [Objective] To explore the structure diversity of the microbial community in cucumber rhizospheric soil under the in situ treatment of waste by earthworms and the treatment with desulfurization gypsum for soil improvement, and reveal the relationship between the number of soil microorganisms and microbial diversity indexes. [Methods] We determined the number of cultivable fungi, bacteria, and actinomycetes in the cucumber rhizospheric soils treated with three different amendments (T1–T3), and employed Biolog-ECO microplate method to study the metabolic functions of microbial communities. We then compared the number and metabolic function diversity between the in-situ treatment of waste by earthworms (T1), the treatment with desulfurization gypsum (T2), and the combination of the above two treatments (T3). [Results] The number of cultivable actinomycetes of T1 and T3 treatments was significantly higher than that of CK and T2, and that of bacterial and fungal colonies had no significant difference among treatments. The AWCD values of different treatments presented an upward trend, rising rapidly within 0–96 h and then slowly to the maximum. The AWCD values of T1 and T3 were higher than those of CK and T2. The AWCD, Shannon index, Simpson index, Pielou index, and McIntosh index all showed significant differences among treatments. Compared with CK, T1 and T2 had efficient carbon source utilization. The number of bacteria and actinomycetes had positive correlations with AWCD value, Shannon index, Simpson index, McIntosh index, and Pielou index (p<0.05 or p<0.01), while that of cultivable fungi was negatively correlated with AWCD value, Shannon index, Simpson index, McIntosh index, and Pielou index (p<0.05 or p<0.01). [Conclusion] Upon the in situ treatment of waste by earthworms, the soil can harbor more microbial communities with higher diversity and higher efficiency of carbon source utilization, which reveals the good performance of earthworms in the treatment of waste and the corresponding changes of ecological functions under the new cultivation mode. The findings of this study are expected to provide a theoretical basis for new cultivation modes.