枯草芽孢杆菌RSS-1R菌株在油菜植株和土壤中的 定殖以及对微生物种群数量的影响

通过双抗药性标记法(抗利福平和硫酸链霉素)和扫描电子显微镜观察法研究了枯草芽孢杆菌RSS-1R菌株在油菜植株和根际土壤的定殖。结果表明,喷雾处理后2~6 d内,油菜植株上RSS-1R菌株的平均菌量从3.67×105 cfu·g-1鲜组织下降到1.00×103 cfu·g-1鲜组织;到处理后10 d,油菜植株上即检测不到RSS-1R菌株;喷雾处理30 d内,油菜根际土壤中菌株RSS-1R种群数量呈现出先上升后下降的趋势。灌根处理后,菌株RSS-1R可在油菜根际土壤中稳定定殖30 d以上,且其种群数量无显著变化。同时研究了RSS-1R菌株对油菜周围微生物种群数量的影响。结果表明,喷雾处理2~10 d后,油菜植株上的细菌种群数量由6.30×106 cfu·g-1湿土下降到3.00×105 cfu·g-1湿土,处理后10 d,油菜植株上的细菌种群数量恢复到对照水平。喷雾处理10 d内油菜根际土壤中的细菌种群数量与对照差异不显著,但是处理后20 d,油菜根际土壤中的细菌种群菌量显著增加。灌根处理后,油菜根际土壤中的细菌种群数量呈现出先增加后下降的趋势,处理后30 d,油菜根际土壤中的细菌种群数量恢复到对照水平。无论是喷雾还是灌根处理均不影响油菜植株或根际土壤中的真菌和放线菌的种群数量。

Colonization of Bacillus subtilis strain RSS-1R on rapeseed plants and in rhizospheric soil and its influence on the quantity of microbial population around rapeseed plants

The double resistance labeling technique (Rifampicin and Streptomycin) and scanning electron microscope observation were adopted to investigate the colonization of Bacillus subtilis strain RSS-1R on rapeseed plants and in the rhizospheric soil. The results indicated that RSS-1R population on rapeseed plants significantly decreased after spraying of RSS-1R suspension, which was reduced from 3.67×10⁵ cfu·g^-1 fresh tissue at 2 days post-inoculation (dpi) to 1.00×10³ cfu·g^-1 fresh tissue at 6 dpi. RSS-1R was not detected on rapeseed plants since 10 dpi; whereas, the RSS-1R population showed a tendency of increase first and then decrease in the rhizospheric soil during the period of 30 dpi. RSS-1R could stably colonize at least 30 d in the rhizospheric soil without significant change of the population after the treatment of irrigating root. The quantity of microbial population on rapeseed plants and in the rhizospheric soil was also analyzed in this study. The results showed that the quantity of bacteria on rapeseed plants was obviously decreased after spraying with RSS-1R suspension, which was reduced from 6.30×10⁶ cfu·g^-1 wet soil at 2 dpi to 3.00×10⁵ cfu·g^-1 wet soil at 10 dpi, and then the bacteria