Biochar significantly alters rhizobacterial communities and reduces Cd concentration in rice grains grown on Cd-contaminated soils.
Biochar significantly alters rhizobacterial communities and reduces Cd concentration in rice grains grown on Cd-contaminated soils.
复制标题
DOI：
10.1016/j.scitotenv.2019.04.133
复制
发表时间：
2019-08
期刊：
影响因子：
--
通讯作者：
Runze Wang;Shuai Wei;Peihan Jia;Ting Liu;Dandi Hou;Ruohan Xie;Zhi-min Lin;Jun Ge;Yabei Qiao;Xiao-yan Chang;Lingli Lu;S. Tian
中科院分区：
文献类型：
--
作者：
Runze Wang;Shuai Wei;Peihan Jia;Ting Liu;Dandi Hou;Ruohan Xie;Zhi-min Lin;Jun Ge;Yabei Qiao;Xiao-yan Chang;Lingli Lu;S. Tian
镉(Cd)污染是水稻土中的一个严重问题。生物炭可以抑制土壤中Cd的活性，减少水稻植株中Cd的积累，但很少有研究涉及生物炭是否以及如何影响水稻根际微生物群落，这是决定金属生物有效性和植物生长的一个重要因素。利用电感耦合等离子体质谱(ICPMS)和16SRRNA基因测序技术，研究了在不同Cd污染土壤中生长的高积累量(HA)和低积累量(LA)水稻品种中生物炭对水稻吸收Cd的影响以及对低积累量(LA)水稻根际细菌群落的影响。施用生物炭显著降低了两个品种水稻植株中Cd的含量，在污染严重的土壤中生长的LA的籽粒Cd含量显著降低。施入生物炭后，土壤pH略有升高。土壤中Cd的生物有效性有所降低，但没有水稻植株中Cd含量的降低那么显著。更有趣的是，生物炭的应用显著改变了根际细菌群落：它刺激了促进生长的细菌，如Kaistbacter、Sphingobium(鞘氨醇单胞菌目)和根瘤科(根瘤菌目)；改善了天然屏障的形成和根际周围金属动员的转化，如红环科(Beta Proteacteria)和Gebacter(DeltaProtebacia)；并促进了可能参与Cd固定的类群(Desulfovibrionales和Desulfobterales)对LA根际的定植。这些结果表明，生物炭通过改变镉污染土壤上种植的水稻根际细菌群落，显著降低了水稻对镉的吸收和积累。这项研究产生的基线数据提供了一些见解，为更安全的大米生产铺平了道路。
Cadmium (Cd) contamination poses a serious problem in paddy soils. Biochar is frequently reported to deactivate Cd in soils and reduce Cd accumulation in rice plants, but few studies have addressed whether and how biochar affected the microbial communities in rice rhizosphere, which was an important factor determining the metal bioavailability and plant growth. In this study, biochar was pyrolyzed from bamboo (Phyllostachys heterocycla) chips at 350 °C. By using ICP-MS analysis and 16S rRNA gene sequencing, the impact of the biochar on Cd uptake by rice and on rhizospheric bacterial communities was investigated in both high-accumulating (HA) and low-accumulating (LA) rice cultivars grown in soils artificially contaminated with different Cd levels. Applied biochar significantly reduced Cd contents in rice plants of both cultivars, with substantially lower grain Cd contents for LA grown in highly contaminated soil. Soil pH was slightly increased by the applied biochar. Cd bioavailability was somehow reduced in soils, but not as significant as the reduction of Cd contents in rice plants. More interestingly, biochar application significantly altered the rhizobacterial community: it stimulated growth-promoting bacteria, such asKaistobacter,Sphingobium(order Sphingomonadales), andRhizobiaceae(order Rhizobiales); improved natural barrier formation and the transformation of metal mobilization around the rhizosphere mediated by, e.g.,Rhodocyclaceae(class Betaproteobacteria) andGeobacter(class Deltaproteobacteria); and enhanced colonization of the LA rhizosphere possibly by taxa involved in Cd immobilization (Desulfovibrionales and Desulfobacterales). These results indicate that biochar application significantly reduces Cd uptake and accumulation by altering the rhizosphere bacterial community in rice grown on Cd-contaminated soils. The baseline data generated in this study provide insights that pave the way toward safer rice production.