枯草芽孢杆菌TR21在香蕉体内及根际的定殖动态

通过浓度梯度诱导法，获得了抗链霉素300 μg/ml、菌落形态及对香蕉枯萎病菌拮抗活性保持不变的枯草芽孢杆菌（Bacillus subtilis）TR21标记菌株，并采用伤根、灌根和叶腋接种法，研究了其在香蕉体内及根际的定殖情况。结果表明，采用伤根和灌根法接种，标记菌株均能够在香蕉体内定殖和传导，伤根接种定殖总量最大，接种后1 d，球茎中菌量达3.33×106 cfu?g-1，且标记菌株在香蕉根表和根际土壤中也显示出很好的定殖能力，接种后15 d，根表菌量分别为6.18×103 cfu?g-1、5.53×103 cfu?g-1，根际土壤中菌量分别为1.13×104 cfu?g-1、1.04×104 cfu?g-1；2种接种方法中，标记菌株在香蕉体内及根际的定殖动态总体呈下降趋势。采用叶腋法接种，标记菌株仅能在叶片中定殖，其定殖动态表现为“由升到降”趋势。

Colonization of Bacillus subtilis Strain TR21 in Banana Plant and Rhizosphere

In order to investigate the colonization of Bacillus subtilis strain TR21 in banana plant and rhizosphere with different inoculation methods, colonizing dynamics of TR21 marked strain in banana plant, root surface and rhizosphere soil were investigated with inoculations of injuring root, drenching root and dropping leaf axil. The results showed that the most amount of the marked strain were 4.18 × 10 3 cfu/g or 2.28×10 3 cfu/g in root when inoculated by injuring root and drenching root methods, respectively, and 1 d after inoculation, the population of marked strain were 3.33×10 6 cfu/g or 6.5×10 2 cfu/g in corm, respectively; 15 d after inoculation, the population of marked strain in root surface were 6.18 × 10 3 cfu/g or 5.53 × 10 3 cfu/g, respectively, and in the rhizosphere soil were 1.13×10 4 cfu/g or 1.04×10 4 cfu/g, respectively; with these two inoculation methods, the population of marked strain showed the downward trend generally in banana plant, root surface and rhizosphere soil during 1 to 15 d after inoculation. Inoculated by dropping leaf axil method, the marked strain could only colonize in leaf, the population showed a trend ＂ first increasing then decreasing ＂ . The TR21 strain could colonize and transfer in banana tissues when inoculated by three methods, and it also displayed good colonization in the rhizosphere soil and root surface.