PGPR对莠去津污染土壤中结缕草生长及生理的影响

PGPR in Atrazine Contaminated Soil:Effect on the Growth and Physiology of Zoysia japonica Steud

探究接种植物根际促生菌(PGPR)对结缕草幼苗生长与生理代谢的影响,为莠去津污染土壤中种植草坪草提供理论依据。采用双因素试验设计,以结缕草幼苗为材料,将幼苗分为PGPR(荧光假单胞杆菌,Pseudomonas fluorescens)接种和未接种两组,进行莠去津处理(浓度梯度为0、3、15、75 mg/kg),并测定不同莠去津浓度下接种PGPR对结缕草的生长指标、防御性酶活性、光合参数和叶绿素荧光参数的影响。结果表明,接种荧光假单胞杆菌促进了结缕草生长,对不同浓度的莠去津胁迫均具有一定的缓解作用,其中3 mg/kg莠去津浓度下接种菌剂的促进作用最为明显,与对照相比,接菌后结缕草叶片叶绿素a、b分别提高45.8%和39.5%;净光合速率(Pn)增加184.83%;最大光化学效率(Fv/Fm)和PSII潜在活性(Fv/Fo)分别提高9.9%和41.04%;过氧化物酶(POD)活性、可溶性蛋白和脯氨酸含量分别是对照的2.96倍、1.94倍和2.37倍;结缕草株高、地上部鲜重及地上部干重分别比对照增加71.43%、47.69%和78.13%。综上,接种PGPR可促进结缕草的生长,增加叶绿素含量,提高光合作用能力,对缓解低浓度莠去津毒害效果显著。

To provide a theoretical basis for planting Zoysia japonica Steud seedlings in atrazine contaminated soil,the effects of plant rhizosphere growth promoting bacteria(PGPR)on plant growth and physiological characteristics of Zoysia japonica Steud seedlings in atrazine contaminated soil were investigated.A two-factor experimental design was conducted.One-year-old Zoysia japonica Steud seedlings were used as materials,the seedlings were divided into two groups of PGPR(Pseudomonas fluorescens)inoculated and non-inoculated,and treated with atrazine(concentration gradient:0,3,15,75 mg/kg).The growth index,defensive enzyme activity,photosynthetic parameters and chlorophyll fluorescence of the seedlings under different atrazine concentrations were measured.The results showed that the inoculation of Pseudomonas fluorescens promoted the growth of Zoysia japonica Steud and alleviated the stress of atrazine at different concentrations.And the promoting effect of inoculation was the most obvious at the atrazine concentration of 3 mg/kg.Compared with the non-inoculated plants,the chlorophyll a and b of Zoysia japonica Steud leaves increased by 45.8%and 39.5%,respectively;net photosynthetic rate(Pn)increased by 184.83%;the maximum photochemical efficiency(Fv/Fm)and PSII potential activity(Fv/Fo)increased by 9.9%and 41.04%,respectively;peroxidase(POD)activity,soluble protein and proline content were 2.96,1.94 and 2.37 times that of those of the control,The plant height,shoot fresh weight and dry weight of Zoysia japonica Steud increased by 71.43%,47.69%and 78.13%,respectively.In conclusion,PGPR inoculation can promote the growth of Zoysia japonica Steud,increase chlorophyll content,improve photosynthesis,and has a significant effect on alleviating the toxicity of low concentration atrazine.