The Selecting Of Sainfoin Rhizobium And Bionomics Study In Alpine Region

Based on the 28 rhizobium strains of sainfoin collected from Gannan area in Gansu province, screened out 8 comprenhensively excellent-expressed strains according to phenotype and metabolic characteristics research.(1) When synthesizing colony formation time and rhizobium generation, the result indicated that all the tested strains were fast-growing rhizobium, among all of which, the fastest strain STD111IB, whose generation time reached 1.07h. Most strains'generation time were between 2-4h.(2) Observed the tested strains after 10 months'process under minus 10 degrees condition , 23 strains grew normally, which accounted for 82 percent of the total number, except STF11IA, STD11IIB, STD1-11IA, STD1-11IIA and STD411IIA. It was concluded that sainfoins in this area had strong cold-resistence ability. Screened out 10% NaCl-resistance strains STD 111 IA, STD26 IB, STD411 IB, STF11 IA; cultivated strains HND26 IA, HND26 IB, HND26 II, STD111 IA, STD26 IB, STD411 IA and STD 411 IIA on culture medium at the PH value of 4.0; strains HND 26 IA, HND26 IB, HND26 II, STD111 IA, STD111 IB,STD 11 IB, STD 26 IB, STD411IB, STF11 IA and STF 11 IIIA can be cultivated on culture medium at the PH value of 11.0. The strain STF 11 IIIA can grew on culture medium at the PH value of 12.0, whose alkali-tolerent ability was strongest among all the strains. According to comprehensive analysis, strains HND26ⅠA , HND26ⅠB , HND26Ⅱ, STD111ⅠA and STD26ⅠB were stronger in both alkali and acid tolerent ability, and can grew well in both acid and alkali culture mediums at the PH value of 4.0 and 11.0, respectively. According to comprehensive evaluation, strains STD 111 IA and STD 26 IB owned strongest comprehensive stress resistance ability, and can grew under acid stress of 10% NaCl, at the PH value of 4.0 along with the alkali stress at the PH value of 11.0.(3) The acid and alkali secretion test indicated that all of the 28 tested strains owned acid-secreting ability. Strains of strong acid-secreting ability often owned strong alkali-secreting ability. Strain STF 11 IIIA was the strongeat in both acid and alkali secreting ability.(4) 13 of the 28 tested strains owned phosphorous resolving ability, the 3 strains, HBD 26 IA, HND 26 II and HND 26 IB, which collected in Hezuo owned the strongest phosphorous ability. Took D/d ratio as relative index of phosphorous resolving ability, the 3 D/d ratio were 1.51, 1.49 and 1.46, respectively.(5) According to the growth hormone secreting ability test, all of the 28 strains varied obviously. The strongest growth hormone secreting strains were STF 26 IA and STD 11 IA, which were 9.87mg/ml and 9.41mg/ml, respectively. (6) All the 28 strains owned stronger nitrogenase activity, with the strongest strain STD 411 IIB, which as high as 7.50mmolC2H4/ml/h.(7) Established the best multivariated linear regression equation between total nitrogen, nitrogenase activety, above ground biomass and various character index respectively: total nitrogen ? = ?=21.8773+0.6679X7-0.4315X8+0.1239X10;above ground biomass ? = 0.4263+0.1841X5+0.0391X7+1.4132X11; (X1= total nitrogen, X2 = salt-resistance, X3 = alkali-resistance, X4 = acid-resistance, X5 = phosphorous resolving, X6 = growth hormone secretion, X7 = acid secretion, X8 = generation time, X9 = nitrogenase activety, X10 = root nodule number, X11 = root nodule weight, X12 = above ground biomass).(8) Evaluated cultured and metabolic characteristics of various sainfoins'rhizhobium by using grey system correlation theory and dicision method in fuzzy mathematics method, the obtained weighted cofficient sort by counting was: total nitrogen> alkali-resistance > acid-resistance> phosphorous resolving> nitrogenase activety> above ground biomass > Rhizobium strains weight> Rhizobium strains number> acid-resistance>generation time> growth hormone secretion> salt-resistance(9) Established rhizobium strain materials'comprehensive appraisal model as follow:ψ= 0.117ζ1 +0.060ζ2 +0.103ζ3 +101ζ4 +0.090ζ5 +0.061ζ6 +0.070ζ7 +0.068ζ8 +0.089ζ9 +0.073ζ10 +0.083ζ11+0.085ζ12 (ζ1 was total nitrogen,ζ2 was salt resistance,ζ3 was alkali resistance,ζ4was acid resistance,ζ5was phosphorous resolving,ζ6was growth hormone secretion, was acid secretion ability,ζ8was generation time,ζ9was nitrogenase activity,ζ10was root nodule number,ζ11 was root nodule weight,ζ12was above ground biomass).(10) Scored on the 28 rhizobium strains according to synthetical evaluation model. Screened out 15 strains that comprehensively excellent expressed, and ranked in order, was STD11ⅠA,STD411ⅠB,STD411ⅡB,STD26ⅠB,STD411ⅠA,STF11ⅠB,STF11ⅢA,HND26ⅠA,STD11ⅠB,STD411ⅡA,HND26Ⅱ,STD111ⅡA,STD26ⅡB,STF11ⅡA,STF26ⅠA respectively. Among which, STD11ⅠA scored highest at 6.886 and STD11ⅡA,STD111ⅠA scored lowest at 5.401.