酸快生芽孢杆菌‘HS3’培养条件的优化及其在玉米花生间作体系中的促生效果

Effects of optimal multifunctional growth-promoting bacteria‘HS3’on maize and peanut growth in a maize-peanut intercropping system

【目的】高效多功能微生物可以改善作物根际环境,提高肥料利用率。我们筛选并验证了一株多功能促生菌对作物的“增产提质”效应。【方法】供试促生菌分离筛选自花生根际土,利用“稀释涂布平板法”获得一株兼具产吲哚乙酸(indole acetic acid,IAA)、溶有机磷、解钾能力的高效多功能促生菌,结合形态学、生理生化及16S rDNA序列分析方法鉴定其种属,通过单因素和正交试验探究其促生能力最佳条件,并将其应用在花生盆栽以及花生玉米大田间作条件下,探究其在实际生产中的应用价值。【结果】1)筛选出的菌株登记号为‘HS3’,属于酸快生芽孢杆菌(Bacillus acidiceler),其产IAA、溶有机磷、解钾能力分别达45.82、2.86和19.88 mg/L。其最佳产IAA能力和解钾能力的培养条件为:初始pH 6、装液量100 mL/250 mL、果糖、酵母粉;最大溶有机磷能力的培养条件为pH 6、装液量100 mL/250 mL、蔗糖、尿素。2)盆栽试验中,接种‘HS3’后,土壤IAA、有效磷、速效钾含量分别提高了80.95%、14.24%、70.59%,并显著促进了花生根系和地上部的生长。3)在田间花生玉米间作体系下,接菌处理花生侧土壤IAA、有效氮、有效磷、速效钾含量分别显著提高了49.06%、22.64%、24.01%、52.89%,单株秕果数和单株秕果重分别显著下降了54.26%和47.90%,花生产量显著提高9.87%;玉米侧土壤IAA、有效磷、速效钾含量分别显著提高了67.83%、22.94%、14.17%,玉米穗秃顶长下降了27.30%,玉米产量显著提高18.56%。相关性分析结果表明,花生玉米间作田间试验中土壤IAA、速效磷和速效钾含量均与花生和玉米产量呈显著正相关。【结论】筛选得到的一株酸快生芽孢杆菌‘HS3’具有较好的产IAA、溶有机磷和解钾的功效。接种于土壤中可以有效提高土壤IAA、速效磷、速效钾含量,进而促进植株的地上部和地下部生长,提高产量。

【Objective】Multifunctional microorganisms greatly improve crop rhizosphere environment and enhance fertilizer utilization efficiency.This study screened a multifunctional growth-promoting bacteria and verified its‘yield increasing and quality improving’effect on crops.【Methods】Growth-promoting bacteria were isolated and screened from peanut rhizosphere soil.The species were identified based on morphology,physiology,biochemistry,and 16S rDNA sequence.We used the plate dilution method to achieve the highest indole-3-acetic acid(IAA)producing capacity and organo-P and K dissolvability.Pot and field experiments of peanut-maize intercropping were conducted with and without‘HS3’isolation.【Results】The strain‘HS3’belongs to Bacillus acidiceler.Its IAA production,organo-P and K solubilization capacity were 45.82 mg/L,2.86 mg/L,and 19.88 mg/L.The optimum culture conditions for the highest IAA production were 30℃,32 h of inoculation,pH 6,100 mL/250 mL liquid volume,and fructose and yeast as C and N sources.The optimum culture conditions for the highest organo-P solubility were pH 6,100 mL/250 mL liquid volume,and sucrose and urea as C and N sources.Compared with no‘HS3’isolation control in the pot experiment,‘HS3’isolation treatment increased the contents of IAA,available P and K by 80.95%,14.24%,and 70.59%.It also(P<0.05)increased the growth of the root and shoot of the peanut.In the field experiments,‘HS3’inoculation improved IAA,available N,available P,and available K content in peanut soil by 49.06%,22.64%,24.01%,52.89%,and IAA,available P,available K by 67.83%,22.94%,14.17%in maize soil,respectively.As a result,‘HS3’inoculation decreased the number and weight of blighted fruit per plant by 54.26%and 47.90%,respectively,increased peanut yield by 9.87%,maize yield by 18.56%,and decreased the bald length of maize ear by 27.30%.The results of correlation analysis showed that the soil IAA content,available phosphorus and available potassium were positively correlated with peanut and maize yield.【Conclusions】The screened multifunctional probiotic Bacillus acidiceler strain‘HS3’showed the prospect of improving soil available P and readily available K content,and promoting the aboveground and underground of plant growth.