丛枝菌根化翅果油树幼苗根际土壤微环境

Rhizospheric soil of seedlings of Elaeagnus mollis colonized by arbuscular mycorrhizal fungi

以我国二级濒危保护植物翅果油(Elaeagnus mollis)为供试植物,通过温室盆栽试验,研究接种丛枝菌根真菌对翅果油树幼苗根际土壤微生态环境的影响。试验设计分4个组:摩西球囊霉(Glomus mosseae)单独接种组(GM)、脆无梗囊霉(Acaulospora delicata)单独接种组(AD)、混合接种组(GM+AD)、不接种的对照组(CK)。测定了菌根侵染率、生物量、根际微生物数量、土壤pH值、土壤酶活性及其对N、P营养的影响等指标。结果显示:菌根真菌对3个接种组均有侵染,其中,GM+AD的侵染率最大(90.5%),生态学效应最好;与对照组相比,接种组的生物量均明显提高(p<0.05),其中GM+AD组生物量显著增加,是CK组的2.2倍;AM菌根对根部微生物种群数量产生一定的影响,主要是使根面上的细菌、放线菌、固氮菌的数量显著增加(p<0.05);AM菌根使根际pH值降低,与菌根侵染率呈显著负相关关系(p<0.05);接种组根际土壤磷酸酶、脲酶、蛋白酶的活性增加,根际土壤的磷酸酶、蛋白酶的活性增加量与菌根侵染率呈极显著相关关系(p<0.01);接种组的根际土壤中,可直接被植物吸收利用的N、P元素出现富集现象,与菌根侵染率呈显著相关关系(p<0.05)。研究表明:丛枝菌根的形成改善了翅果油树幼苗的微生态环境,提高了根际土壤肥力。

Aim Arbuscular mycorrhizal （AM） fungi were inoculated into the seedlings of Elaeagnus mollis,an endangered plant in China. Our objectives were to study the impact of AM fungi inoculation on the soil micro-area in the rhizosphere of E. mollis seedlings using a greenhouse pot experiment. Methods The experimental design included separate inoculation （Glomus mosseae = GM or Acaulospora delicata = AD） and mixed inoculation （GM ＋ AD）; control groups were not inoculated. We determined the infection rate of AM fungi,biomass,infection rate of mycorrhizae,number of microorganisms in the rhizosphere,soil pH,soil enzyme activity,N and P nutrients in the rhizosphere,etc. Important findings AM fungi infected the three inoculated groups,among which the infection rate of GM ＋ AD was the greatest,up to 90.5%. Compared with the control group,the biomass of inoculated groups improved markedly （p 0.05） and the biomass of the GM ＋ AD group was 2.2 times that of the CK group. AM mycorrhizae impacted microbial populations on the roots; the number of bacteria,actinomycetes and nitrogen-fixing bacteria on the root surface increased significantly （p 0.05）. The AM mycorrhizae made the pH in the rhizosphere de-crease,and this was significantly negatively correlated with the infection rate （p 0.05）. The activity of soil phosphatase,urease and protease in the rhizosphere of inoculated groups increased. Moreover,the increase of their activity was significantly correlated with mycorrhizal infection rate （p 0.01）. The phenomenon that the N and P elements directly absorbed by plants enriched the rhizosphere soil of inoculated groups was significantly correlated with the mycorrhizal infection rate （p 0.05）. AM formation improved the micro-ecological environment of E. mollis seedlings and increased soil fertility in the rhizosphere.