金属抗性促生菌对玉米生长和锌积累的影响

摘要

Objective]Effects of metal resistant plant growth promoting bacteria ( PGPB ) on corn growth and Zn accumulation were studied to provide a fundamental groundwork for mitigating the stress of heavy metal on crop growth and decreasing heavy metal uptake .[Method] A pot experiment was carried out to study the effects of inoculation with two Zn resistant PGPB ,Ⅱ2 R3 andⅣ8 R3 on corn plant growth and Zn uptake from Zn contaminated soils (0, 200, 400 and 800 mg· kg -1 Zn addition).[Result and conclu-sion] The strains Ⅱ2 R3 and Ⅳ8 R3 not only grew well with different concentrations of Zn , but also ab-sorbed or accumulated much higher Zn from the growing medium .Individual inoculation of strain Ⅳ8 R3 to the soil with 200 or 400 mg· kg -1 Zn addition both promoted the corn growth .For the soils with 800 mg· kg -1 Zn addition , simultaneous inoculation with strains Ⅱ2 R3 andⅣ8 R3 promoted the corn growth . Individual or simultaneous inoculation with strains Ⅱ2 R3 andⅣ8 R3 to the soils at three Zn pollution levels (200, 400 and 800 mg· kg -1 Zn addition) decreased the soil bioavailable Zn concentration .For the soil with a high Zn pollution level ( 800 mg · kg -1 Zn addition ) , the inoculation of strains Ⅱ2 R3 orⅡ2 R3 +Ⅳ8 R3 decreased Zn uptake and transportation in corn .However, all of three inoculation treatments had no significant effects on Zn uptake of corn when strains Ⅱ2 R3 ,Ⅳ8 R3 ,Ⅱ2 R3 +Ⅳ8 R3 were inoculated to the soils with 200 or 400 mg· kg -1 Zn addition.The results indicate that inoculation with metal resistant PGPB to high Zn-contaminated soil can promote the corn growth and inhibite the uptake and transporta-tion of Zn in corn .Inoculation with strains Ⅱ2 R3 orⅣ8 R3 to high Zn-contaminated soils can inhibite the uptake and transportation of Zn in corn .The effects of inoculation with strains Ⅱ2 R3 or Ⅳ8 R3 on corn growth are related to the different levels of Zn pollution and characterization of the strains .%目的探讨金属抗性促生菌对锌污染土壤中玉米生长和Zn吸收的影响，为利用微生物缓解重金属对农作物胁迫和减少重金属吸收提供理论依据。方法通过盆栽试验研究接种促生菌Ⅱ2 R3和Ⅳ8 R3是否能够缓减Zn对玉米的毒害作用，减少玉米对Zn的吸收和积累。结果和结论促生菌Ⅱ2 R3、Ⅳ8 R3不仅有很强的抗Zn胁迫能力，而且具有较强地吸附、积累Zn的能力。在中、轻度Zn污染（200和400 mg· kg －1）土壤上，单独接种促生菌Ⅳ8 R3促进了玉米的生长；当土壤Zn污染水平达到800 mg· kg－1时，同时接种促生菌Ⅳ8 R3＋Ⅱ2 R3显著促进玉米的生长。单独或同时接种促生菌Ⅳ8 R3、Ⅱ2 R3使不同Zn污染水平土壤中的有效Zn含量均显著降低。当土壤Zn含量达到800 mg· kg－1时，单独接种菌株Ⅱ2 R3或同时接种Ⅱ2 R3＋Ⅳ8 R3均显著抑制玉米对Zn的吸收和向地上部转运，而在中、轻度Zn污染（Zn≤400 mg· kg－1）土壤上，3种接种处理对玉米吸收Zn均没有显著影响。表明在高锌污染（800 mg· kg－1）土壤中，接种促生菌Ⅳ8 R3、Ⅱ2 R3能显著抑制玉米对Zn的吸收和向地上部转运；菌株Ⅳ8 R3、Ⅱ2 R3对玉米生长的影响与土壤Zn污染水平和菌株的性质有关。