不同根瘤菌与紫云英主栽品种的共生匹配性

Symbiotic compatibility of different rhizobia strains with important Chinese milk vetch(Astragalus sinicus)cultivars

研究不同根瘤菌与我国紫云英主栽品种的共生匹配性,筛选广谱且固氮能力强的菌株用于接种,对提高紫云英固氮能力具有重要的实践意义。本研究以8株分离自不同主产区的根瘤菌和8个紫云英主栽品种为研究对象,水培试管验证8株根瘤菌中有6株可以与8个主栽品种建立良好的共生关系,选取共生效果较好的4株进行蛭石盆栽复筛试验,测定紫云英的有效瘤数、根瘤鲜重、固氮酶活性、干重、氮素积累量。结果显示,与不接种的阴性对照相比,接种根瘤菌能显著增加紫云英的干重和氮素积累量。不同紫云英品种与4株复筛菌株共生固氮体系中地上部及地下部干重、地上部及地下部氮素积累量分别是不接种对照的3。23~7。12倍、1。64~4。12倍、12。72~37。84倍和5。42~13。63倍。不同紫云英品种与4株复筛菌株共生固氮体系的固氮能力有差异,弋江籽、宁波大桥与4株复筛菌株共生固氮体系中的地上部及地下部干重、地上部及地下部氮素积累量显著高于信紫1号,分别是信紫1号的1。78~1。87倍、1。68~1。99倍、1。14~2。08倍、1。74~2。40倍。菌株7653R与8个主栽品种的共生固氮体系中平均有效瘤数、根瘤鲜重、固氮酶活性显著大于其他3株菌株,是其他3株菌株的1。17~1。19倍、1。15~1。22倍、1。38~1。45倍。双因素交互分析显示根瘤菌菌株对紫云英的有效瘤数、根瘤鲜重、干重、氮素积累量的贡献率为50。79%~87。64%,大于紫云英品种(7。17%~32。83%)。本研究初步建立了不同根瘤菌菌株与紫云英主栽品种的匹配关系,为在田间试验中进一步筛选和应用这些菌株提供了理论支撑。

Symbiotic compatibility of different rhizobia strains with important Chinese milk vetch(CMV)cultivars was studied to identify rhizobia with a broad host compatibility high nitrogen fixation ability for CMV crop inoculation,with a view to improving CMV nitrogen fixation ability and performance.Eight rhizobia strains isolated from different geographic CMV production regions and eight important CMV cultivars were used in the research.A hydroponic tube test showed six of the eight rhizobia strains could establish good symbiosis with all of the eight tested CMV cultivars.Four rhizobia strains with better symbiosis were re-tested in a vermiculite pot experiment in which the effective nodule number,nodule fresh weight,nitrogenase activity,dry weight,and nitrogen accumulation of CMV were recorded and analyzed.It was found that compared with the uninoculated control,rhizobia inoculation significantly increased the dry weight and nitrogen accumulation of CMV.Across the eight tested CMV cultivars and four rhizobia strains,CMV shoot dry weights were 3.23-7.12 times higher and root dry weights were 1.64-4.12 times higher in inoculated than in uninoculated plants.Similarly,shoot nitrogen accumulation was 12.72-37.84times higher,and root nitrogen accumulation 5.42-13.63 times higher in inoculated plants than in the control treatment.There were also differences between CMV cultivars and rhizobia strains in nitrogen fixation ability.The eight cultivars tested differed in their response to inoculation.CMV cultivars Yijiangzi and Ningbodaqiao were generally more responsive,and cultivar Xinzi No.1 was generally less responsive.For cultivars Yijiangzi and,Ningbodaqiao,shoot dry weight was 1.78-1.87 times higher;root dry weight was 1.68-1.99 times higher;shoot nitrogen accumulation was 1.14-2.08 times higher and root nitrogen accumulation was 1.74-2.40 times higher than for cultivar Xinzi No.1.Among the four rhizobia strains re-tested in the pot trial,strain 7653R was superior to the other three(13005,13025 and 13052).Averaged over the eight tested CMV cultivars,the effective nodule number was 1.17-1.19 times higher;the nodule fresh weight was 1.15-1.22 times higher,and nitrogenase activity was 1.38-1.45 times higher for rhizobia strain 7653R than for the other 3 strains.ANOVAs for CMV and rhizobia strain effects and their interaction showed that the contribution of rhizobia strains to effective nodule number,nodule fresh weight,nodule dry weight,and nitrogen accumulation was 50.79%-87.64%,compared with a7.17%-32.83%contribution of CMV cultivars.Symbiotic compatibilities among different rhizobia strains and the main CMV cultivars were elucidated,and these data provide a knowledge base for further screening of rhizobia strains with excellent field performance.