中科院南京土壤研究所林先貴研究員課題組在叢枝菌根真菌的最新研究中發(fā)現(xiàn),，磷肥的施用有利于我國北方潮土地力的提升,。
叢枝菌根真菌是陸地生態(tài)系統(tǒng)中關(guān)鍵的微生物,。它們參與了碳,、氮,、磷等多種元素的生物地球化學(xué)循環(huán)過程,，能與90%以上的陸地植物形成互惠共生體。通過“生物地下交易”法則,，植物和叢枝菌根真菌進(jìn)行著物質(zhì)和能量的交換：植物將光合產(chǎn)物以碳源的形式輸送給叢枝菌根真菌,；作為反饋，叢枝菌根真菌為植物吸收更多的養(yǎng)分和水分等,，以促進(jìn)植物生長,。此外，植物根據(jù)環(huán)境的變化,，會“選擇性”地放棄某些叢枝菌根真菌伙伴,，將光合產(chǎn)物分配給其它微生物，以促進(jìn)土壤肥力的可持續(xù)性發(fā)展,。因此,，叢枝菌根真菌群落不但可以表征土壤質(zhì)量和健康,，還可以敏銳地反映土壤生態(tài)系統(tǒng)的變化。
基于此理論,，林先貴課題組利用中科院封丘農(nóng)業(yè)生態(tài)實(shí)驗(yàn)站的農(nóng)田生態(tài)系統(tǒng)養(yǎng)分平衡長期定位試驗(yàn),，通過454高通量基因測序技術(shù)研究了長期不同施肥措施對潮土中叢枝菌根真菌的影響。通過高通量測序,，獲得了59611個叢枝菌根真菌（Glomeromycota）特異性片段序列,，形成70個OTUs，主要分為三個科Glomeraceae,，Gigasporaceae和Acaulosporaceae,。與對照和施用NK的處理相比，長期施用磷肥顯著減少了潮土中叢枝菌根真菌的豐富度和多樣性,，其群落結(jié)構(gòu)也發(fā)生明顯的分異,。結(jié)合環(huán)境因子的統(tǒng)計分析進(jìn)一步顯示，在施用N肥的基礎(chǔ)上添加P肥有助于潮土肥力的提升,。當(dāng)作物可直接從土壤中獲得足夠的養(yǎng)分時,，其對叢枝菌根真菌的依賴性下降，進(jìn)而會“舍棄”部分叢枝菌根真菌,，將更多的光合產(chǎn)物分配給其它土壤微生物,，以促進(jìn)土壤養(yǎng)分的循環(huán)過程。
這一研究結(jié)果首次深度揭示了典型農(nóng)田土壤中叢枝菌根真菌群落對不同施肥的響應(yīng),，為合理施肥提供了理論依據(jù)和科學(xué)指導(dǎo),。該研究成果發(fā)表在Environmental Science & Technology上（生物谷Bioon.com）
doi:10.1021/es3001695
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Long-Term Balanced Fertilization Decreases Arbuscular Mycorrhizal Fungal Diversity in an Arable Soil in North China Revealed by 454 Pyrosequencing
Xiangui Lin*, Youzhi Feng, Huayong Zhang, Ruirui Chen, Junhua Wang, Jiabao Zhang, and Haiyan Chu
A balanced fertilization can increase crop yields partly due to stimulated microbial activities and growths. In this study, we investigated arbuscular mycorrhizal fungi (AMF) in arable soils to determine the optimal practices for an effective fertilization. We used pyrosequencing-based approach to study AMF diversity, as well as their responses to different long-term (>20 years) fertilizations, including OM (organic manure) and mix chemical fertilizers of NP (nitrogen–phosphorus), NK (nitrogen–potassium), and NPK (nitrogen–phosphorus-potassium). Results revealed that 124 998 of 18S rRNA gene fragments were dominated by Glomeromycota with 59 611 sequences, generating 70 operational taxonomic units (OTUs), of which the three largest families were Glomeraceae, Gigasporaceae and Acaulosporaceae. In Control and NK plots, AMF diversity and richness significantly decreased under long-term P fertilizations, such as NP, NPK, and OM. Concomitantly, the AMF community structure shifted. Supported by canonical correspondence analysis, we hereby propose that long-term balanced fertilization, especially P fertilizer with additional N fertilizer, helps the build-up of soil nutrients. Consequently, some AMF community constituents are sacrificed, propelled by the self-regulation of plant-AMF-microbes system, resulting in an agro-ecosystem with a better sustainability. This knowledge would be valuable toward better understandings of AMF community in agro-ecosystem, and long-term ecosystem benefits of the balanced fertilization.
