FH-1和NJ-1混合菌发酵液缓解铅与莠去津复合胁迫下的大豆生长

Mitigation of Soybean Growth under Combined Lead and Atrazine Stress by FH-1 and NJ-1 Mixed Bacterial Fermentation Broth

为探究FH-1和NJ-1混合菌发酵液缓解铅(Pb^(2+))与莠去津复合胁迫对大豆种子及幼苗生长发育的影响。本研究采用液相色谱法测定了不同Pb^(2+)浓度下FH-1和NJ-1(3∶2)混合细菌对莠去津降解的影响。结果表明:添加0.02,0.04,0.06,0.08,0.1和0.2mol·L^(-1)Pb^(2+)后,第1天时低浓度0.02mol·L^(-1)Pb^(2+)对莠去津降解率有促进作用,随着Pb^(2+)浓度的增加莠去津降解率均受到抑制作用;当培养第3天和第5天时,添加各浓度Pb^(2+)后莠去津降解率均受到抑制作用。同时种子萌发试验和幼苗盆栽试验进一步表明,Pb^(2+)与莠去津复合胁迫对大豆种子萌发、幼苗生长及根部发育均有显著抑制作用(P<0.05),且高于单一胁迫;而加入FH-1和NJ-1混合菌发酵液后,大豆种子发芽率和发芽长度分别提高了36.36%和46.76%。幼苗的相对茎叶干重和根长分别恢复38.60%和60.20%。此外,FH-1和NJ-1混合菌发酵液灌根后,将Pb^(2+)与莠去津复合胁迫下大豆幼苗根部SOD和POD活性分别提高了38.21%和6.17%,MDA含量降低了59.27%。而添加混合菌发酵液后使受Pb^(2+)与莠去津复合胁迫影响下土壤的根系活力与细菌数量分别恢复了37.63%和37.55%。因此FH-1和NJ-1混合菌发酵液可以通过诱导抗性提高抗氧化酶活性与根系活力,减轻Pb^(2+)与莠去津复合胁迫下对大豆的伤害,进而促进幼苗生长。

To investigate the effects of the fermentation broth of mixed bacteria FH-1 and NJ-1 in mitigating the combined stress of lead(Pb^(2+))and atrazine on the growth and development of soybean seeds and seedlings.The effects of mixed bacteria FH-1 and NJ-1 on the degradation of atrazine at different concentrations of Pb^(2+)were determined by liquid chromatography.The experimental results indicate that,after adding 0.02,0.04,0.06,0.08,0.1 and 0.2 mol·L^(-1)Pb^(2+).At the first day,the low concentration of 0.02 mol·L^(-1)Pb^(2+)promoted the degradation rate of atrazine,and with the increase of Pb^(2+)concentration,the degradation rate of atrazine was inhibited.At the third and fifth days of culture,the degradation rate of atrazine was inhibited by adding Pb^(2+)atrazine at different concentrations.The results of seed germination test and seedling pot test showed that the combined stress of Pb^(2+)and atrazine significantly inhibited soybean seed germination,seedling growth and root development(P<0.05),and was higher than that of single stress;while the germination length and germination rate of soybean seeds increased by 46.76%and 36.36%,respectively,after the addition of mixed bacterial fermentation broth.Meanwhile,the relative stem and leaf dry weight and root length of seedlings were restored by 38.60%and 60.20%,respectively.In addition,root irrigation with the mixed bacterial fermentation solution increased the SOD and POD activities of seedlings roots under complex stress by 38.21%and 6.17%,respectively,and reduced the MDA content by 59.27%.And the reduced root vigor and bacterial population in the soil affected by the combined stress recovered 3763%and 37.55%,respectively,after the addition of the mixed bacterial fermentation broth.Therefore,the fermentation broth of FH-1 and NJ-1 mixed bacteria can improve the antioxidant enzyme activity and root vigor to mitigate the damage of Pb^(2+)and atrazine combined stress on soybean seedlings,and then promote seedling growth.