两种Cd积累型番茄品种联合土著微生物对土壤有效态Cd的影响

Effects of two Cd-accumulating varieties of tomato combined with indigenous microorganisms on soil available Cd

  • 摘要: 镉(Cd)在作物体内的累积能力主要受土壤Cd有效性决定, 为降低Cd积累和保障作物安全, 本研究以低Cd积累型‘普罗旺斯’和高Cd积累型‘合作908’番茄品种为研究对象, 结合Illumina MiSeq测序, 探讨番茄和土著微生物共同作用对土壤中有效态Cd及微生物多样性的影响。试验设置背景土壤(Cd含量0.24 mg∙kg−1)和Cd污染土壤(Cd含量0.60 mg∙kg−1)的灭菌(无土著微生物)与不灭菌(有土著微生物)处理, 在此基础上, 分别设置不种植番茄、种植‘合作908’和‘普罗旺斯’处理。结果表明: 在背景土壤和Cd污染土壤中, ‘合作908’吸收积累土壤Cd的能力均显著高于‘普罗旺斯’。与不种植(CK)相比, 在灭菌土壤种植‘普罗旺斯’和‘合作908’的单一作用使污染土壤有效态Cd含量分别增加3.16%和5.26%; 不灭菌土壤的土著微生物单一作用使污染土壤有效态Cd增加27.37%; 不灭菌土壤种植‘普罗旺斯’和‘合作908’(与土著微生物联合)比在灭菌土壤中作物单一种植使土壤有效态Cd含量分别增加29.59%和28.00%, 比不灭菌土壤(土著微生物单一作用)分别提高4.96%和5.79%。与CK处理相比, 不灭菌污染土壤种植‘普罗旺斯’和‘合作908’使土壤鞘氨醇单胞菌属(Sphingomonas)、微鞘藻属(Microcoleus)、Haliangium和爬管菌属(Herpetosiphon)相对丰度均明显增加。同时, 在不灭菌污染土壤种植‘普罗旺斯’处理中游动放线菌属(Actinoplanes)和硝化螺菌属(Nitrospira)相对丰度增加, 而在不灭菌污染土壤种植‘合作908’处理中噬氢菌属(Hydrogenophaga)和溶杆菌属(Lysobacter)相对丰度增加, 两处理间存在着明显的差异菌属。这些优势菌属可能与两种积累型番茄品种种植下的土壤有效态Cd含量差异有关。综上, 两种积累型番茄品种-土著微生物的联合作用提高了土壤微生物的多样性, 改变了土壤细菌群落结构, 显著提升了土壤中有效态Cd的含量。

     

    Abstract: Accumulation of heavy metal cadmium (Cd) in vegetable field soils poses significant concerns owing to various pathways. Excessive Cd not only induces severe toxicity in animals and plants but also poses substantial risks to human health through the food chain. Biological toxicity and Cd accumulation in organisms are influenced not only by the total amount of Cd in the soil, but also by its activity. Under the influence of crop roots, various soil microorganisms affect the migration, release, and absorption of Cd in multiple ways. Current research on soil Cd availability and microorganisms has primarily focused on identifying Cd-resistant bacteria in soil and enhancing Cd-contaminated soil phytoremediation by introducing external microorganisms. However, native microorganisms are abundant, and comprehensive data on how their combination with different Cd-accumulating crops affects Cd bioavailability, plant absorption and accumulation characteristics are lacking. In particular, it remains unclear whether the combination of various Cd-accumulation varieties of solanaceous fruits and their native microorganisms influence soil Cd bioavailability, thereby affecting variations in Cd absorption and accumulation. The accumulation of Cd in crops is primarily determined by its availability in the soil. In the early stages, our research group selected tomato varieties with high Cd accumulation (‘Hezuo 908’) and low Cd accumulation (‘Provence’). Through solution culture experiments, we found that ‘Hezuo 908’ had a greater effect on the activation of insoluble Cd than ‘Provence’. To address the issue of Cd accumulation and ensure crop safety, our study focused on ‘Provence’ and ‘Hezuo 908’ tomato varieties. Using Illumina MiSeq sequencing, we investigated the effects of tomatoes and indigenous microorganisms on soil available Cd levels and microbial diversity. The experiment involved treating the background soil (with 0.24 mg∙kg−1 Cd) and Cd-contaminated soil (with 0.60 mg∙kg−1 Cd) with (without indigenous microorganisms) and without sterilization (containing indigenous microorganisms). Subsequently, ‘Hezuo 908’ and ‘Provence’ were planted separately. The results indicated that ‘Hezuo 908’ had a significantly higher capacity to absorb and accumulate soil Cd compared to ‘Provence’ in both types of soil. Planting ‘Provence’ and ‘Hezuo 908’ in sterilized soil increased the available Cd content in contaminated soil by 3.16% and 5.26%, respectively, compared to the control group with no planting. Moreover, the presence of indigenous microorganisms in unsterilized soil led to a 27.37% increase in available Cd in contaminated soil. When ‘Provence’ or ‘Hezuo 908’ were planted in non-sterilized soil alongside indigenous microorganisms, the available Cd content in soil increased by 29.59% or 28.00%, respectively, compared to single crop planting, and by 4.96% or 5.79%, respectively, compared to the sole presence of indigenous microorganisms. Compared with the control treatment, planting ‘Provence’ and ‘Hezuo 908’ in unsterilized contaminated soil significantly increased the relative abundance of Sphingomonas, Microcoleus, Haliangium, and Herpetosiphon. Additionally, the relative abundances of Actinoplanes and Nitrospira increased in the non-sterile soil planting ‘Provence’ treatment, while Hydrogenophaga and Lysobacter increased in the non-sterile contaminated soil planting ‘Hezuo 908’ treatment, demonstrating distinct differences among the bacteria genuses. These dominant bacteria may be linked to the varying available Cd content in the soil planted with the two tomato varieties. In conclusion, the combined effects of these tomato varieties and indigenous microorganisms enhanced soil microorganism diversity, altered the community structure of soil bacteria, and notably increased the available Cd content in soil.

     

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