植物根际促生菌（PGPR）对缓解水稻受土壤锌胁迫的作用

为解决农田重金属污染的严重环境问题,提出利用植物根际促生菌（Plant growth-promoting rhizobacteria,PGPR）来缓解农作物受重金属胁迫的科学设想。研究从大宝山污染土壤中筛选出的Pb2＋、Cd2＋、Cu2＋、Zn2＋耐性菌株,经鉴定为芽孢杆菌属（Bacillussp.DBM）,菌株DBM具有产吲哚乙酸（IAA）和ACC脱氨酶能力,但无产铁载体能力。盆栽试验结果表明,菌株DBM在水稻受重金属Zn（600mg.kg-1）胁迫时能有效保护并促进水稻的生长,使其地上部和地下部干重比不加菌处理对照分别提高97.8%和77.2%。另外,菌株DBM可以增加土壤中Zn的有效态含量,但不能增强水稻对土壤Zn的吸收能力。相反,在Zn600处理下,水稻地上部和地下部Zn浓度分别比不加菌处理对照减少15.1%和19.9%。但由于促生效果也极为显著,其地上部和地下部Zn总量仍分别比不加菌处理对照增加74.2%和48.6%。

Application of Plant Growth-promoting Rhizobacteria（PGPR） for Reducing Zinc Stress on Paddy Rice

The heavy metal pollution in soils has become an increasing problem in China.This study focused on the application of plant growth-promoting rizobacteria（PGPR） to reduce heavy metal stress on crops.One Pb2＋,Cd2＋,Cu2＋,Zn2＋ resistant bacteria,Bacillus sp.DBM,was isolated from contaminated soils of Dabao Mountain.Strain DBM showed some plant growth promoting properties such as producing indole-3-acetic acid（IAA）and 1-aminocyclopropane-1-carboxylate（ACC）deaminase,but it could not produce siderophores.A pot experiment was conducted to study the effects of strain DBM on the plant growth and heavy metal uptake of paddy rice grown in different levels of Zn-contaminated soils.Results showed that the inoculation with strain DBM remarkably increased the growth of host plant,but did not enhance Zn extraction by rice.Growing in the soils with 600 mg·kg-1 Zn,the dry weights of shoot and root of rice treated with strain DBM increased by 97.8% and 77.2%,respectively,and the Zn concentrations in the shoot and root were reduced by 15.1% and 19.9%,respectively,compared to the non-inoculated control.However,total Zn uptakes both in the shoot and root of rice still increased by 74.2% and 48.6%,respectively,which mostly attributed to the remarkable promotion of plant growth by strain DBM.