从烟草根际土壤分离到107个细菌分离物,通过室内平板对峙培养筛选,筛选到13株对烟草黑胫病菌有拮抗作用的菌株,其中,LZ-7菌株的室内平板抑菌效果最好,抑菌圈直径达27.82 mm。经盆栽试验,LZ-7、A3控病作用较好,防治效果分别达59.12%和55.84%。通过16 S rDNA序列测定与分析,LZ-7与Bacillus pumilus的同源性为99%,初步鉴定证明该菌株属于短小芽孢杆菌。
[Objective] This study was conducted to investigate the effects of different plant spacing on tobacco grade structure, growth stages, agronomic traits, yield and chemical composition under fixed row spacing. [Method] Under fixed row spacing （120 cm）, 4 treatments were designed （40, 50, 60 and 45 cm）. The growth stages, agronomic traits, economic traits and chemical composition of flue-cured tobacco leaves were compared and analyzed. [Result] with the increase of plant spacing, there were no significant differences in the emergence time of growth stages be- tween different treatment groups before resettling stage, and the resettling stage ap- peared 1-2 d in advance. At different tobacco growth stages, the changing trends of tobacco agronomic traits with the change of plant spacing were different. [Conclusion] With the increase of plant spacing, the planting density of tobacco de- creased, and the nicotine content increased; and the yield of tobacco decreased continuously, while the quality was improved, but when the plant spacing was im- proved to certain degree, the quality of tobacco also decreased, and at the plant spacing of 50 cm, the output value of tobacco was the highest.
