梭梭根际枯草芽孢杆菌WM13⁃24对多年生黑麦草耐盐性的影响

Induced salt tolerance of ryegrass by Bacillus subtilis strain WM13⁃24 from the rhizosphere of Haloxylon ammodendron

以从梭梭根际分离得到的促生细菌枯草芽孢杆菌WM13⁃24为供试菌株,大肠杆菌DH5α和枯草芽孢杆菌GB03分别为阴性对照和阳性对照,研究WM13⁃24对多年生黑麦草耐盐性的影响。结果表明:1)在不同浓度NaCl处理(0,150和300 mmol/L)下,接种WM13⁃24提高了黑麦草的生物量、叶绿素含量、根长和根系活力。尤其是在150 mmol/L NaCl胁迫下,与空白对照相比,接种WM13⁃24处理的黑麦草植株叶绿素a和叶绿素b含量分别显著提高44.05%和53.79%,根长和根系活力分别显著提高69.21%和49.47%(P<0.05);300 mmol/L NaCl胁迫下,根长和根系活力分别显著提高24.07%和58.48%(P<0.05)。2)不同浓度NaCl胁迫下,接种WM13⁃24提高了黑麦草的过氧化氢酶活性,降低了相对质膜透性和丙二醛含量。尤其是在300 mmol/L NaCl胁迫下,与空白对照相比,接种WM13⁃24显著提高黑麦草叶片过氧化氢酶活性64.21%,相对质膜透性和丙二醛含量分别显著降低了24.56%和54.24%(P<0.05)。3)不同浓度NaCl胁迫下,接种根际有益细菌提高了黑麦草的可溶性糖和脯氨酸含量,降低了叶片渗透势,尤其在300 mmol/L NaCl胁迫下,与空白对照相比,接种WM13⁃24分别显著提高黑麦草叶片可溶性糖和脯氨酸含量84.41%和82.71%(P<0.05)。4)接种根际有益细菌提高了在不同浓度NaCl胁迫下黑麦草地上部和根中的K+含量,降低了Na+含量,从而提高了K+/Na+比,尤其是在300 mmol/L NaCl胁迫下,与空白对照相比,接种WM13⁃24显著提高根中的K+/Na+比87.93%(P<0.05)。本研究结果为利用荒漠植物根际促生细菌提高草类植物耐盐性和在盐碱地区建植牧草和草坪草奠定了一定的理论和实践基础。

In this paper,the effects of a PGPR strain,Bacillus subtilis WM13⁃24 isolated from the rhizosphere of Haloxylon ammodendron,on salt tolerance of perennial ryegrass(Lolium perenne)were investigated.At the same time,Escherichia coli DH5αand B.subtilis GB03 were used as the negative control and the positive control,respectively.The results were as follows:1)under various salt treatments(0,150 and 300 mmol/L NaCl),inoculation of WM13⁃24 increased the biomass,chlorophyll content,root length and root vigour of ryegrass.Especially,under 150 mmol/L NaCl,inoculation of WM13⁃24 increased the contents of leaf chlorophyll a and chlorophyll b significantly by 44.05%and 53.79%,respectively,and the root length and root vigour significantly by 69.21%and 49.47%,respectively,compared with the blank control(P<0.05).Under 300 mmol/L NaCl,root length and root vigour were increased significantly by 24.07%and 58.48%by inoculation of WM13⁃24,respectively(P<0.05).2)Under various NaCl treatments,inoculation of WM13⁃24 increased catalase(CAT)activity and reduced relative membrane permeability(RMP)and malondialdehyde(MDA)content of ryegrass.Especially,under 300 mmol/L NaCl,CAT activity of ryegrass was increased significantly by 64.21%,and relative membrane permeability and MDA content were reduced significantly by 24.56%and 54.24%by inoculation of WM13⁃24,respectively(P<0.05).3)Under various NaCl treatments,inoculation of the PGPR strains increased soluble sugar and proline contents and reduced osmotic potential of ryegrass.Especially,under 300 mmol/L NaCl,the contents of soluble sugar and proline in ryegrass plants inoculated with WM13⁃24 were significantly increased by 84.41%and 82.71%,respectively(P<0.05).4)Inoculation of the PGPR strains increased K+content in both shoots and roots of ryegrass under various NaCl treatments,and decreased Na+content,resulted in increased K+/Na+ratio.Especially,under 300 mmol/L NaCl,root K+/Na+ratio of ryegrass plants inoculated with WM13⁃24 was increased significantly by 87.93%(P<0.05).In summary,this study laid a theoretical and practical basis for the application of PGPR from the rhizosphere of desert plants in improving the salt tolerance of grass and forage plants and cultivating forage crops and turf grasses in saline⁃alkali areas.