抗性烤烟品种根际微生物数量及功能多样性差异

以青枯病和黑胫病不同抗性烤烟品种‘红花大金元’、‘云烟-87’和‘K326’为材料(对青枯病和黑胫病的抗性均表现为K326>云烟87>红大),在石林和寻甸两个不同生态区进行田间试验,采用平板稀释计数法和Biolog技术研究不同抗性品种不同生育期根际微生物群落动态及功能多样性的差异.结果表明: 烤烟根际土壤细菌、放线菌和微生物总量与品种抗性均呈正相关,而真菌数量与品种抗性呈负相关;两地移栽后35、55和75 d均有一致规律.不同品种根际微生物对6类碳源的利用和碳源利用率(AWCD)存在一定差异,其中寻甸点移栽后55和75 d抗病烤烟品种对糖类、氨基酸类、羧酸类、多聚物类和胺类的利用程度比感病品种高,而移栽后75 d对酚酸类的利用刚好相反;移栽后55和75 d抗病品种的AWCD值显著大于感病品种.而石林点移栽后35、55和75 d根际微生物对6类碳源的利用能力和AWCD值虽与品种抗性无明显相关关系,但3个品种之间有显著差异.主成分分析表明,两地不同品种根际微生物碳源利用特征均存在差异,且在PC1和PC2上有较好的体现,以移栽后55和75 d差异最显著.表明不同抗性品种间根际微生物的群落结构和功能多样性存在差异,且同一品种因栽培环境的不同，其根际微生物的群落结构和功能多样性也有所变化.

Difference of rhizosphere microbe quantity and functional diversity among three flue-cured tobacco cultivars with different resistance.

Field experiments were conducted in Shilin and Xundian respectively to study the diffe rence of rhizosphere microbe quantity and functional diversity with plate culture method and Biolog technique among Hongda (high susceptibility, S), Yun87 (middle resistance, MR) and K326 (high resistance, R), three flue-cured tobacco cultivars with different resistance to bacterial wilt and black shank. The results indicated that the amounts of bacteria, actinomycetes and the total number of microbes in tobacco plants’ rhizosphere were positively correlated with the cultivar’s resistance, while it was opposite for the fungi. The consistent tendency was obtained not only at 35 d, 55 d and 75 d after transplanting, but also at two experimental sites. Cultivar and experimental conditions greatly affected the utilization of six types of carbon source by rhizospheric microbes, as well as the AWCD value. In Xundian site, rhizospheric microbes’ utilization of carbohydrates, amino acids, carboxylic acids, polymers, amines and the AWCD value were all higher at 55 d and 75 d after transplanting for the resistant cultivar than the susceptible one, but it was opposite at 75 d after transplanting for the phenolic acids. In Shilin, significant differences existed among the three cultivars at 35 d, 55 d and 75 d after transplanting for the indices mentioned above, although they were not consistent with cultivars’ resistance. Principal component (PC) analysis even showed that utilization of carbon sources by rhizosphere microorganisms differed significantly among the three cultivars at the two sites, and it was better reflected by PC1 and PC2 at 55 d and 75 d after transplanting, respectively. In conclusion, rhizosphere microbial community structure and functional diversity were greatly affected not only by the cultivars’ difference in resistance, but also by experimental conditions.