接种AMF提高干旱胁迫下土壤微生物活性和燕麦抗旱能力

AMF inoculation positively regulates soil microbial activity and drought tolerance of oat

【目的】研究接种AMF(arbuscular mycorrhiza fungi)提高干旱胁迫下土壤微生物生物量和酶活性,及提高土壤养分有效性的效果,为旱作区作物生产提供菌根调控技术。【方法】盆栽试验连续进行了两年,供试燕麦品种为‘坝莜18号’,栽培基质为生土与河沙以3∶1混合,每盆添加N 0.315 g、P2O50.087 g。试验设两个土壤相对含水量(田间持水量的75%和55%),并分别设接种AMF和不接种AMF处理,共4个处理。在燕麦抽穗期取样测定土壤微生物特性指标和养分含量,及燕麦各器官氮、磷积累量;成熟期测定燕麦籽粒产量。【结果】接种AMF条件下,55%土壤相对含水量处理的燕麦根系AMF侵染率比75%土壤相对含水量处理显著降低23.28%~33.35%。与正常水分条件相比,干旱胁迫显著降低了土壤微生物生物量碳和酶活性,降低了土壤有效氮、磷含量,pH和有机碳含量升高。干旱胁迫下,与未接种AMF相比,接种AMF显著提升了土壤微生物生物量碳、氮和磷含量,提高了土壤蔗糖酶、脲酶和碱性磷酸酶活性,速效磷含量显著增加了4.92%~5.41%,有机碳和pH无显著变化;显著增加了燕麦根、茎、叶和穗部氮、磷积累量,籽粒产量显著提高了14.20%~14.74%。接种AMF、土壤pH和速效磷是影响土壤微生物特性的主要因子。土壤微生物生物量氮和脲酶活性是影响土壤养分有效性的主要因子。速效磷是影响燕麦氮、磷积累量和产量的主要因子。【结论】接种AMF提高了干旱胁迫条件下燕麦根系的AMF侵染率,提高了根际土壤微生物活性和酶活性,提高了根际土壤中速效磷含量,进而提高了燕麦各器官氮、磷积累和籽粒产量,增加了燕麦的抗旱性。

【Objectives】We studied the effects of arbuscular mycorrhizal fungi(AMF)inoculation on soil microbial properties and soil nutrient availability under drought stress,to provide a mycorrhizal regulation technology to enhance the drought resistance of oat in dryland areas.【Methods】Pot experiments were conducted for two years,using the mixture of calcareous cinnamon soil and river sand at a ratio of 3 to 1 as cultural substrates(adding N 0.315 g and P2O50.087 g per pot).The soil relative water content(RWC)of 75% and 55% of field water capacity and inoculating with and without AMF(Rhizophagus intraradices)composed four treatments.At the heading stage of oats,the soil microbial characters,nutrient contents were analyzed.The nitrogen(N)and phosphorus(P)accumulation in various parts of oat plant,and the grain yield were recorded at maturity stage.【Results】The AMF infecting rate in oat roots under 55%RWC was 23.28%-33.35% lower than that under 75%RWC with AMF inoculation.Drought stress significantly reduced the soil microbial biomass,enzyme activities,available N and P;and increased the soil pH and organic carbon.AMF inoculation under drought stress significantly increased MBC,MBN,MBP,and invertase,urease and alkaline phosphatase activities,significantly increased the available P by 4.92%-5.41%,but did not change soil organic carbon and pH.Further,the N and P accumulation in oat root,stem,leaf,and ear were significantly increased,and grain yield was significantly increased by 14.20%-14.74%.AMF inoculation,soil pH and available P was the main factors affecting soil microbial characters;Soil MBN and urease activity were the main factors affecting soil nutrients;available P was the main factor benefitting oat plants.【Conclusions】AMF inoculation under drought stress increased the infection rate of AMF in oat roots,enhanced the microbial mass and enzyme activities,mobilized more P in rhizosphere soil,thus increased the N and P accumulation in various parts of the oat plant and oat grain yield.Therefore,AMF inoculation is an effective way to enhance the drought resistance of oat.