| 添加磷素对低磷稻田根际土壤固碳自养微生物数量的影响 |
| 摘要点击 1841 全文点击 710 投稿时间：2018-03-29 修订日期：2018-06-04 |
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| 中文关键词 磷素 低磷水稻土 根际土壤 固碳自养微生物 丰度 |
| 英文关键词 phosphorus phosphorus-limited paddy soil rhizosphere soil autotrophic CO2-fixation microorganism gene abundance |
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| 中文摘要 |
| 为了探讨磷素添加对低磷稻田土壤固碳自养微生物数量的影响，以低磷水稻土为研究对象，设置添加磷素（P添加量为80 mg·kg-1）和不添加磷素两种处理土壤，种植水稻进行室内培养实验.利用实时荧光定量PCR（real-time PCR）技术分析了水稻分蘖期（移栽后14 d）和拔节期（移栽后22 d）添加磷素（P）和对照（CK）处理根际土壤固碳自养微生物cbbL、cbbM、accA和aclB基因数量的差异，同时测定了土壤理化性质，并分析了不同处理方式下固碳功能基因丰度与土壤理化性质之间的关系.结果表明，分蘖期磷素添加降低了土壤MBC和NH4+-N含量，提高了土壤DOC、Olsen-P和pH；分蘖期P处理NO3--N含量比CK处理低，而拔节期反而比CK处理高.分蘖期，磷素添加显著提高了cbbL、cbbM、accA和aclB基因的数量，与CK处理相比，分别提高156%、99%、110%和193%.而磷素添加对拔节期cbbL、accA和aclB基因数量的促进作用并不明显，对cbbM基因数量反而产生了抑制作用.冗余分析（RDA）显示，土壤Olsen-P含量是影响固碳自养微生物丰度最显著的环境因子. |
| 英文摘要 |
| A rice pot experiment was conducted to investigate the effect of phosphorus addition on the abundance of autotrophic CO2-fixation microorganisms using phosphorus-limited paddy soil from the Changsha Observation and Research Station for the Agricultural Environment. Rice seedlings were transplanted in the paddy soil with or without phosphorus addition, corresponding to P-treated-pot (P) or control pot (CK), respectively. Rhizosphere soils were collected from the P and CK treatments during the tillering and shooting stages. The physical and chemical soil properties were measured and the abundance of autotrophic CO2-fixation microorganisms was quantified with a real-time PCR technique based on four functional genes (cbbL, cbbM, accA, and aclB) involved in three CO2-fixation pathways (CBB cycle, rTCA cycle, and 3-hydroxypropionate/4-hydroxybutyrate cycle). The results show that phosphorus addition improves the concentrations of DOC and Olsen-P and the pH value, whereas negative effects on the MBC and NH4+-N concentrations are revealed during the tillering stage. The effect of phosphorus addition on the NO3--N concentration in the tillering and shooting stages differs. Phosphorus addition significantly increases the abundances of the cbbL, cbbM, accA, and aclB genes, which are 156%, 99%, 110%, and 193% higher than those of the CK treatment in the tillering stage. However, this positive effect is not notable for the cbbL, accA, and aclB genes during the shooting stage. Redundancy analysis (RDA) shows that Olsen-P is the environmental factor that most significantly affects the abundance of autotrophic CO2-fixation microorganisms. |
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