生物炭–过氧化钙复合颗粒对酚酸胁迫下番茄生长和根际微生态的调控效应

  【目的】  酚酸胁迫是造成番茄连作障碍的主要因素之一。本研究探讨了生物炭–过氧化钙复合颗粒(简称复合颗粒)作为土壤改良剂缓解番茄酚酸胁迫的效果和机理。  【方法】  供试番茄品种为千禧圣女果，供试土壤为赤红壤。盆栽试验共设5个处理:常规栽培(CK)，酚酸胁迫处理(T1)，添加外源酚酸的同时分别添加生物炭–过氧化钙复合颗粒(T2)、生物炭颗粒(T3)、过氧化钙颗粒(T4)，其中土壤酚酸胁迫浓度为140 μg/g。在番茄移栽后30和120天，测定了番茄生长和生理指标。在收获期，调查果实产量与品质，分析根际土壤理化性状，并使用高通量测序技术解析番茄根际土壤中细菌和真菌的群落结构特征。  【结果】  施用复合颗粒(T2处理)能够增强番茄根系活力，促进植株生长发育；单株番茄果实产量、单果重和糖酸比分别比T1处理增加了13.8%、20.1%和52.6%。与T1处理相比，T2处理番茄收获期根际土壤中残余总酚酸含量下降了44.6%，电导体 (EC)值下降17.7%，pH提高0.77个单位，有机质含量增加77.4%。复合颗粒处理能够改善酚酸胁迫下番茄根际土壤微生物群落结构，使细菌多样性提高，真菌多样性降低，并有效恢复微生物群落的均衡性。Spearman相关性热图分析和冗余分析结果显示，番茄产量和体现品质的糖酸比与土壤残余总酚酸含量和EC值呈负相关，与pH值和有机质含量正相关。生物炭–过氧化钙复合颗粒可通过去除土壤酚酸，降低EC值，提高土壤pH和有机质含量，并介导增加与番茄果实产量和糖酸比具有正相关关系的拟杆菌门和壶菌门的相对丰度，而对与番茄产量和糖酸比呈负相关的酸杆菌门和子囊菌门起抑制作用。  【结论】  土壤残留总酚酸、pH、有机质含量、EC值是驱动番茄根际土壤微生物群落变异，及影响番茄果实产量与品质的主要环境因子。生物炭–过氧化钙复合颗粒可通过对土壤理化性状、细菌和真菌群落的双重调控作用，改善番茄根际土壤微生态环境，从而有效缓解酚酸类物质对番茄生长的化感胁迫效应，实现番茄果实产量和品质的协同提升。

Regulatory effects of biochar-calcium peroxide composite particles on tomato growth and rhizosphere microbial ecology under phenolic acid stress

  【Objectives】  Phenolic acid stress is one of the primary factors limiting continuous cropping of tomato. The impact and mechanism of biochar-calcium peroxide composite particles as soil conditioners in relieving tomato phenolic acid stress were studied.   【Methods】  Pot experiments were carried out with ‘millennium cherry’ tomatoes and latosolic red soil. There were 5 treatments in total, including conventional cultivation (CK), phenolic acid stress treatment (T1), and exogenous phenolic acid together with biochar-calcium peroxide composite particles (T2), biochar particles (T3), and calcium peroxide particles (T4), respectively. The phenolic acid stress content in soil was 140 μg/g. The tomato growth and physiological indicators were examined at 30 and 120 days after transplanting tomato. At the harvest period, fruit production and quality, and rhizosphere soil physicochemical parameters were determined. High-throughput sequencing was employed to investigate the microbial diversity and community structure of in rhizosphere soil of tomato .   【Results】  Compared with T1, T2 treatment enhanced tomato root vigor and promoted plant growth, thus increased the yield, fruit weight and sugar-acid ratio of tomato by 13.8%, 20.1%, and 52.6%, respectively; decreased the total residual phenolic acid content and electrical conductivity (EC) in rhizosphere soil by 44.6% and 17.7%, increased pH by 0.77 units, and enhanced organic matter content by 77.4%. T2 treatment also enriched the microbial community structure, increased bacterial community diversity, reduced fungal community diversity, and effectively restored microbial community balance. According to the Spearman correlation heatmap and redundancy analysis, tomato yield and fruit sugar-acid ratio were negatively related with soil residual total phenolic acid and EC, but positively correlated with soil pH and organic matter content. Other than the reduced soil phenolic acids and EC as well as increased soil pH and organic matter content, the biochar-calcium peroxide composite soil conditioner selectively promoted the relative abundance of Bacteroidetes and Chytridiomycota, which are positively correlated with tomato yield and quality, and suppressed the relative abundance of Acidobacteria and Ascomycota, which are negatively correlated with tomato yield and quality.   【Conclusions】  The key environmental parameters driving the fluctuation of tomato rhizospheric microbial community are the residual total phenolic acid in soil, pH, organic matter content, and EC, which are all strongly related with tomato yield and quality. Through the dual regulation of soil physicochemical properties and microbial communities, biochar-calcium peroxide composite particles improves the micro-ecological environment of tomato rhizosphere, thereby effectively alleviating the allelopathic stress impact of phenolic acids on tomato growth and promoting fruit yield and quality.