欢迎访问林业科学,今天是

林业科学 ›› 2026, Vol. 62 ›› Issue (7): 1-11.doi: 10.11707/j.1001-7488.LYKX20250739

• 前沿热点 •    

杉木−闽楠混交林中闽楠根际土高效解磷菌的分离与功能分析

刘琪燕1,张毓婷1,丁凯1,周一帆1,陈晓明2,张俊红1,*(),童再康1   

  1. 1. 浙江农林大学省部共建亚热带森林培育国家重点实验室 杭州 311300
    2. 广西壮族自治区林业科学研究院 南宁 530002
  • 收稿日期:2025-12-09 修回日期:2026-06-03 出版日期:2026-07-10 发布日期:2026-07-14
  • 通讯作者: 张俊红 E-mail:zhangjunhong@zafu.edu.cn
  • 基金资助:
    国家自然科学基金项目(32201542);浙江省农业新品种选育重大科技专项(2021C02070-10);浙江省大学生科技活动计划暨新苗人才计划资助项目(2025R412B046)。

Isolation and Function Analysis of Phosphate-Solubilizing Bacteria from the Rhizosphere of Phoebe bournei trees in Cunninghamia lanceolataPhoebe bournei Mixed Forests

Qiyan Liu1,Yuting Zhang1,Kai Ding1,Yifan Zhou1,Xiaoming Chen2,Junhong Zhang1,*(),Zaikang Tong1   

  1. 1. Provincial-Ministerial Co-constructed National Key Laboratory of Subtropical Silviculture, Zhejiang A & F University Hangzhou 311300
    2. Guangxi Forestry Research Institute Nanning 530002
  • Received:2025-12-09 Revised:2026-06-03 Online:2026-07-10 Published:2026-07-14
  • Contact: Junhong Zhang E-mail:zhangjunhong@zafu.edu.cn

摘要:

目的: 从杉木?闽楠混交林(简称杉楠混交林)的闽楠根际土中分离、筛选兼具解磷?促生功能的细菌菌株,在拟南芥和1年生杉木无性系幼苗上验证其促生效果,为开发适于南方酸性红壤的杉木专用微生物磷肥提供优良菌种和理论依据。方法: 采用无机磷液体培养基PVK从杉楠混交林的闽楠根际土中分离、鉴定解磷菌;应用溶磷圈法、钼锑抗比色法、Salkowski比色法和96微孔板结晶紫染色法分别测定菌株解磷圈大小、有效磷增量、IAA(吲哚乙酸)分泌量和生物膜形成能力,据此初步筛选出解磷菌;将初筛菌株与拟南芥共培养于1/2 MS培养基中,设置正常磷和低磷2种磷水平处理,根据拟南芥生物量进一步筛选出促生效果最佳的解磷菌,之后进行杉木苗盆栽试验,依据杉木苗的株高、地径、生物量、光合指标和根系形态等指标评价解磷菌的促生效果。结果: 从杉楠混交林的闽楠根际土中共分离到18株解磷菌,来自11个属,其中类芽孢杆菌属和伯克霍尔德菌属为优势类群;18株解磷菌的溶磷能力存在显著差异(P< 0.05),其中P8菌株的有效磷增量最高(1 176.36 mg·L?1),但溶磷圈大小与液体溶磷量无显著正相关;18 株菌均可产生IAA(14.6~22.5 μg·mL?1)并形成生物膜,其中P10菌株IAA产量最高;拟南芥试验显示,在低磷条件下,P17菌株使地下生物量增加398.6%,显著优于其他菌株;杉木盆栽试验表明,P17菌株分别使杉木净光合速率、气孔导度和蒸腾速率达到(7.44±1.49) μmol·m?2s?1、(64.68±19.55) μmol·m?2s?1和(1.81±0.29) mmol·m?2s?1,显著高于对照组(P < 0.01),根表面积和根体积分别增加 66.13%和68.90%(P < 0.01),株高、地径和生物量均较对照组有所增加。结论: 本研究从杉楠混交林的闽楠根际土中分离获得18株解磷菌,其中高效解磷鞘氨醇单胞菌P17可通过活化难溶性磷、分泌IAA优化根系形态、形成生物膜增强根际定殖能力,在低磷胁迫下与植物形成“微生物活化?根系吸收”正反馈,显著提升光合效率和根系体积。P17菌株兼具溶磷、促进植物生长和适应酸性红壤等优良特性,可作为核心菌株用于杉木专用微生物磷肥的研制,为缓解连栽障碍、提升南方人工林磷循环效率提供新路径。

关键词: 解磷菌, 杉木?闽楠混交林, 促生功能, 低磷胁迫, 根际土壤

Abstract:

Objective: Previous studies have demonstrated that the mixed plantations of Cunninghamia lanceolata and Phoebe bournei can significantly enhance rhizosphere soil phosphorus bioavailability. Specifically, the rhizosphere soil of P. bournei within these mixed plantations serves as a critical hotspot for phosphorus activation, exhibiting notably higher levels of labile phosphorus, greater abundances of phosphorus-solubilizing functional genes, and increased diversity of phosphorus-solubilizing bacterial communities compared to both pure C. lanceolata plantations and the rhizosphere of C. lanceolata within the mixed stands. However, highly effective phosphorus-solubilizing bacterial strains with demonstrated plant growth-promoting capabilities have not yet been systematically isolated. Therefore, this study systematically isolated and screened phosphate-solubilizing and growth-promoting bacterial strains from the rhizosphere soil of P. bournei in mixed C. lanceolataP. bournei plantation, and verified their growth-promoting effects on the Arabidopsis thaliana and one-year-old clonal seedlings of C. lanceolata, aiming to provide elite germplasm and a theoretical basis for developing tailor-made microbial phosphorus fertilizers suitable for acidic red soils in southern China. Method: Phosphate-solubilizing bacteria (PSB) were isolated from the rhizosphere of P. bournei on PVK (pikovskaya) selective medium and identified by 16S rRNA sequencing. Solubilizing zone diameter (D/d), available-P increment (Mo-Sb colorimetry), IAA (indole-3-acetic acid) production (salkowski method) and biofilm formation (96-well crystal-violet assay) were determined to preliminarily select ten highly efficient strains. These strains were co-cultured with A. thaliana on standard and low-P 1/2 MS plates to identify the most effective strain based on plant biomass. The optimal strain was further evaluated with potted C. lanceolata seedlings. Plant height, ground diameter, biomass, gas-exchange parameters and root architecture were measured to assess the growth promoting effect of phosphate solubilizing bacteria. Result: 1) A total of 18 PSBs were isolated from the rhizosphere of P. bournei in C. lanceolata and P. bournei mixed plantation, belonging to 11 genera, with Paenibacillus and Burkholderia as the dominant groups. 2) There was a significant difference (P<0.05) in the phosphate-solubilizin ability of 18 strains of phosphate solubilizing bacteria, among which the strain P8 released the highest amount of available P (1 176.36 mg·L?1), but no there was positive correlation existed between the halo size of the phosphorus solubilizing zone and liquid solubilization. 3) All 18 strains of bacteria produced IAA (14.6–22.5 μg·mL?1) and formed biofilms, with P10 having the highest IAA yield. 4) Under low-P conditions, strain P17 increased A. thaliana root biomass by 398.6%, markedly outperforming the full-P treatment. 5) Further pot experiments on Chinese fir showed that P17 raised the net photosynthetic rate, stomatal conductance and transpiration rate to (7.44±1.49) μmol·m?2s?1, (64.68±19.55) μmol·m?2s?1and (1.81±0.29) mmol·m?2s?1, respectively, which were all significantly higher than those of the control group (P<0.01), and P17 inoculation increased root surface area and root volume by 66.13% and 68.90% (P<0.01), and also enhanced plant height, ground diameter, and total biomass. Conclusion: In this study, 18 phosphate-solubilizing bacterial strains have been isolated from the rhizosphere soil of P. bournei in a mixed C. lanceolataP. bournei plantation. Among them, a highly efficient phosphate-solubilizing Sphingomonas strain P17 is obtained. It can mobilize sparingly soluble P, secrete IAA to optimize root architecture and form robust biofilms for rhizosphere colonization. P17 establishes a positive “microbial activation–root absorption” feedback under P-limiting conditions, and markedly enhances photosynthetic efficiency and root volume. The P17 strain has excellent characteristics such as phosphorus solubilization, plant growth promotion, and adaptation to acidic red soil. It can be used as a core strain for developing specialized microbial P fertilizers for C. lanceolata, offering a new strategy to alleviate replant obstacles and improve P-cycling efficiency in southern plantation forests.

Key words: phosphate-solubilizing bacteria, Cunninghamia lanceolata–Phoebe bournei mixed forests, growth-promoting function, low phosphorus stress, rhizosphere soil

中图分类号: