Effects of Microbial Inoculants on Cadmium Uptake, Accumulation, and Root Microbial Community in Rice

doi:10.16819/j.1001-7216.2026.250615

Abstract

Abstract:

【Objective】This study aims to investigate the effect of microbial inoculants on cadmium (Cd) uptake, accumulation, and the root microbial community in rice, providing a theoretical basis for applying green and efficient microbial agents to reduce Cd accumulation in rice grains.【Methods】A field experiment was conducted in Cd-contaminated paddy soil. Microbial inoculant treatments included: 1) seed coating for direct-seeded rice, and 2) foliar spray before transplanting, 3) seed coating + foliar spray 15 days after transplanting for transplanted rice. A control group received no inoculant. At maturity, Cd concentrations in soil, rice roots, stems/leaves, and grains were analyzed. High-throughput 16S rRNA amplicon sequencing was used to characterize microbial community structures in bulk soil, rhizosphere soil, and root endosphere under different treatments.【Results】Microbial inoculants significantly reduced Cd uptake and accumulation in rice. For transplanted rice (seed coating + foliar spray post-transplanting), the Cd uptake factor (UF) and bioaccumulation factor (BF) decreased by 41% and 69%, respectively, compared to the control. The BF in direct-seeded rice with seed coating decreased by 80%. However, no significant effect was observed on the translocation factor (TF). Microbiome analysis revealed that inoculants significantly increased the diversity of root endophytic microbial communities, particularly in transplanted rice. Taxa significantly enriched in the root endosphere under inoculant treatments showed increased relative abundance.【Conclusion】Microbial inoculants reduce Cd uptake by enhancing root endophytic microbial diversity and promoting competition for root binding sites. Furthermore, enriched root endophytic taxa may inhibit Cd absorption via redox reactions, adsorption, or bioaccumulation mechanisms.

Key words: microbial inoculants, rice, cadmium (Cd), rhizosphere microbial community

摘要：

【目的】探究微生物菌剂对水稻吸收富集镉及根系微生物群落的影响，为应用绿色高效的微生物菌剂减少水稻籽粒镉积累提供理论依据。【方法】以镉污染稻田为试验地，微生物菌剂施用设置直播水稻(拌种)和移栽水稻(移栽前喷施秧苗、拌种+移栽后15 d喷施)处理，以不施用微生物菌剂为对照。分析成熟期稻田不同处理下土壤、水稻根、茎叶和籽粒镉含量，并通过高通量扩增子16S rRNA测序分析不同处理下非根际土、根际土和根内微生物群落结构的变化。【结果】微生物菌剂显著降低了水稻对镉的吸收与富集，其中移栽处理(拌种+移栽后喷施)的吸收系数和富集系数较对照分别降低41%和69%，直播拌种处理的富集系数降幅达80%，但对转运系数无显著影响。微生3+物组分析显示，微生物菌剂处理显著提高了水稻根内微生物群落的多样性，尤其在移栽稻中更为明显。且菌剂处理下水稻根内显著富集的微生物类群相对丰度增加。【结论】微生物菌剂通过增加根内微生物群落多样性，竞争植物根系吸收位点来降低对镉的吸收；此外，根内富集的微生物类群可能通过氧化还原、吸附或生物积累等机制抑制根系对镉的吸收。

关键词: 微生物菌剂, 水稻, 重金属镉, 根系微生物群落

TANG Hongwei, WU Yue, ZHU Xinxia, LIU Xuemei, YANG Qing, WANG Danying, LIU Yuanhui. Effects of Microbial Inoculants on Cadmium Uptake, Accumulation, and Root Microbial Community in Rice[J]. Chinese Journal OF Rice Science, 2026, 40(6): 808-820.

汤洪伟, 吴岳, 朱新霞, 刘雪梅, 杨晴, 王丹英, 刘元辉. 微生物菌剂对水稻吸收富集镉及根系微生物群落的影响[J]. 中国水稻科学, 2026, 40(6): 808-820.

Figures/Tables 11

Table 1. Cadmium (Cd) content in rice tissues under different microbial inoculant treatments

处理 Treatment	镉含量 Cd content(mg/kg)				迁移系数Migration coefficient
处理 Treatment	茎叶 Stem and leaf	根 Root	籽粒 Grain	土壤 Soil	吸收系数Absorption coefficient	转运系数Transfer coefficient	富集系数Enrichment factor
移栽农户对照 FTP	2.34 a	4.58 a	0.48 a	0.39 a	11.74	0.51	1.24
移栽拌种+15 d后喷施 SC+FS	1.86 a	2.70 b	0.15 b	0.39 a	6.92	0.69	0.38
移栽前1 d喷施 FSBT	1.58 a	3.36 ab	0.19 b	0.40 a	8.40	0.47	0.49
直播农户对照 FDSP	2.62 a	5.00 a	0.60 a	0.37 a	13.51	0.52	1.62
直播-拌种 DS+SC	2.13 a	4.14 a	0.14 b	0.44 a	9.40	0.51	0.31

Fig. 1. Alpha diversity of microbial communities in rice tissues under microbial inoculant treatments A and B, Direct-seeded rice; C and D, Transplanted rice.

Fig. 2. Beta diversity of microbial communities in rice tissues under microbial inoculant treatments

Fig. 3. Composition of microbial communities in tissues of direct-seeded rice under microbial inoculant treatments

Fig. 4. Composition of microbial communities in tissues of transplanted rice under microbial inoculant treatments

Fig. 5. STAMP analysis of differential microbial taxa in the rhizosphere of transplanted rice under microbial inoculant treatments

Fig. 6. STAMP analysis of differential microbial taxa in bulk soil of transplanted rice under microbial inoculant treatments

Fig. 7. STAMP analysis of differential microbial taxa in the root endosphere of transplanted rice under microbial inoculant treatments

Fig. 8. STAMP analysis of differential microbial taxa in the rhizosphere of direct-seeded rice under microbial inoculant treatments

Fig. 9. STAMP analysis of differential microbial taxa in bulk soil of direct-seeded rice under microbial inoculant treatments

Fig. 10. STAMP analysis of differential microbial taxa in the root endosphere of direct-seeded rice under microbial inoculant treatments

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