Azospirillum brasilense and Pseudomonas fluorescens are well-known plant growth promoting rhizobacteria.However,the effects of A.brasilense and P.fluorescens on the N cycles in the paddy field and rice plant growth ar...Azospirillum brasilense and Pseudomonas fluorescens are well-known plant growth promoting rhizobacteria.However,the effects of A.brasilense and P.fluorescens on the N cycles in the paddy field and rice plant growth are little known.This study investigated whether and how A.brasilense and P.fluorescens contribute to the N transformations and N supply capacities in the rhizosphere,and clarified the effects of A.brasilense and P.fluorescens on the N application rate in rice cultivation.Inoculations with A.brasilense and P.fluorescens coupled with N application rate trials were conducted in the paddy field in 2016 and 2017.The inoculations of rice seedlings included four treatments:sterile saline solution(M_(0)),A.brasilense(M_(b)),P.fluorescens(M_(p)),and co-inoculation with a mixture of A.brasilense and P.fluorescens(M_(bp)).The N application rate included four levels:0 kg N ha^(–1)(N_(0)),90 kg N ha^(–1)(N_(90)),180 kg N ha^(–1)(N_(180)),and 270 kg N ha^(–1)(N_(270)).The results indicated that the M_(bp) and M_(p) treatments significantly enhanced the ammonification activities in the rhizosphere compared with the M_(0) treatment,especially for higher N applications,while the Mbp and M_(b) treatments greatly enhanced the nitrogenase activities in the rhizosphere compared with the M_(0) treatments,especially for lower N applications.Azospirillum brasilense and P.fluorescens did not participate in the nitrification processes or the denitrification processes in the soil.The soil respiration rate and microbial biomass N were greatly affected by the interactions between the rhizobacteria inoculations and the N fertilizer applications.In the M_(bp) treatment,N supply capacities and rice grain yields showed no significant differences among the N_(90),N_(180),and N_(270) applications.The N application rate in the study region can be reduced to 90 kg N ha^(–1) for rice seedlings co-inoculated with a mixture of A.brasilense and P.fluorescens.展开更多
土壤盐渍化降低土壤生产力。探索生物炭对盐胁迫下水稻幼苗耐盐性能的影响,对调控盐渍区水稻生产潜力具有重要意义。本研究通过生物炭介入盐胁迫稻田土壤的盆栽试验,调查了生物炭对盐胁迫下土壤环境和水稻幼苗耐盐性能的影响。盐胁迫设...土壤盐渍化降低土壤生产力。探索生物炭对盐胁迫下水稻幼苗耐盐性能的影响,对调控盐渍区水稻生产潜力具有重要意义。本研究通过生物炭介入盐胁迫稻田土壤的盆栽试验,调查了生物炭对盐胁迫下土壤环境和水稻幼苗耐盐性能的影响。盐胁迫设置4个水平,分别为0 g NaCl·kg^(-1)土(S0),1 g NaCl·kg^(-1)土(S1),2 g NaCl·kg^(-1)土(S2),3 g NaCl·kg^(-1)土(S3)。生物炭设置2个水平,分别为0 g生物炭·kg^(-1)土(C0),3 g生物炭·kg^(-1)土(C1)。结果表明:生物炭介入盐胁迫土壤,显著提高了水稻幼苗地上部干物重,有效改善了水稻幼苗农艺性状,显著提高了水稻幼苗茎秆中全钾含量,显著提高水稻幼苗钾钠比79.61%,提高了水稻幼苗耐盐性。生物炭介入也对水稻幼苗抗氧化性能有改善作用,显著降低了水稻幼苗中丙二醛含量,平均显著降低14.25%,抑制膜脂过氧化作用,提高抗氧化能力,减轻盐胁迫对水稻幼苗的伤害。水稻幼苗收获后土壤中水溶性氯离子和水溶性钠离子含量在生物炭介入条件下分别显著降低9.13%、17.77%。因此,添加适量生物炭能有效降低土壤水溶性盐含量,改善土壤盐胁迫环境,提升水稻对盐渍土壤的适应能力。展开更多
基金This study was financially supported by the National Key Research and Development Program of China(2016YFD0200801,2016YFD0200805)the National Natural Science Foundation of China(31872857)+1 种基金the Foundation of State Key Laboratory of Rice Biology,China National Rice Research Institute(2017ZZKT10404)the Zhejiang Provincial Natural Science Foundation of China(LY16C130007).
文摘Azospirillum brasilense and Pseudomonas fluorescens are well-known plant growth promoting rhizobacteria.However,the effects of A.brasilense and P.fluorescens on the N cycles in the paddy field and rice plant growth are little known.This study investigated whether and how A.brasilense and P.fluorescens contribute to the N transformations and N supply capacities in the rhizosphere,and clarified the effects of A.brasilense and P.fluorescens on the N application rate in rice cultivation.Inoculations with A.brasilense and P.fluorescens coupled with N application rate trials were conducted in the paddy field in 2016 and 2017.The inoculations of rice seedlings included four treatments:sterile saline solution(M_(0)),A.brasilense(M_(b)),P.fluorescens(M_(p)),and co-inoculation with a mixture of A.brasilense and P.fluorescens(M_(bp)).The N application rate included four levels:0 kg N ha^(–1)(N_(0)),90 kg N ha^(–1)(N_(90)),180 kg N ha^(–1)(N_(180)),and 270 kg N ha^(–1)(N_(270)).The results indicated that the M_(bp) and M_(p) treatments significantly enhanced the ammonification activities in the rhizosphere compared with the M_(0) treatment,especially for higher N applications,while the Mbp and M_(b) treatments greatly enhanced the nitrogenase activities in the rhizosphere compared with the M_(0) treatments,especially for lower N applications.Azospirillum brasilense and P.fluorescens did not participate in the nitrification processes or the denitrification processes in the soil.The soil respiration rate and microbial biomass N were greatly affected by the interactions between the rhizobacteria inoculations and the N fertilizer applications.In the M_(bp) treatment,N supply capacities and rice grain yields showed no significant differences among the N_(90),N_(180),and N_(270) applications.The N application rate in the study region can be reduced to 90 kg N ha^(–1) for rice seedlings co-inoculated with a mixture of A.brasilense and P.fluorescens.
文摘土壤盐渍化降低土壤生产力。探索生物炭对盐胁迫下水稻幼苗耐盐性能的影响,对调控盐渍区水稻生产潜力具有重要意义。本研究通过生物炭介入盐胁迫稻田土壤的盆栽试验,调查了生物炭对盐胁迫下土壤环境和水稻幼苗耐盐性能的影响。盐胁迫设置4个水平,分别为0 g NaCl·kg^(-1)土(S0),1 g NaCl·kg^(-1)土(S1),2 g NaCl·kg^(-1)土(S2),3 g NaCl·kg^(-1)土(S3)。生物炭设置2个水平,分别为0 g生物炭·kg^(-1)土(C0),3 g生物炭·kg^(-1)土(C1)。结果表明:生物炭介入盐胁迫土壤,显著提高了水稻幼苗地上部干物重,有效改善了水稻幼苗农艺性状,显著提高了水稻幼苗茎秆中全钾含量,显著提高水稻幼苗钾钠比79.61%,提高了水稻幼苗耐盐性。生物炭介入也对水稻幼苗抗氧化性能有改善作用,显著降低了水稻幼苗中丙二醛含量,平均显著降低14.25%,抑制膜脂过氧化作用,提高抗氧化能力,减轻盐胁迫对水稻幼苗的伤害。水稻幼苗收获后土壤中水溶性氯离子和水溶性钠离子含量在生物炭介入条件下分别显著降低9.13%、17.77%。因此,添加适量生物炭能有效降低土壤水溶性盐含量,改善土壤盐胁迫环境,提升水稻对盐渍土壤的适应能力。