| Tobacco is an important economic crop.The early growth of tobacco in Guizhou tobacco area is susceptible to low temperature environment.Slow growth and frostbite affect tobacco yield and quality.How to increase tobacco seedling stage growth speed and overcome the effects of early cold current is of great significance.In this experiment,strains with low temperature-promoting effects were screened from the rhizosphere of tobacco under low temperature conditions.The strains were isolated from the rhizosphere soil samples of healthy tobacco plants in Guizhou tobacco-growing areas.There are 66 strains were screened by phytohormone secretion test,and 9 strains were screened by confirmatory test.Finally,9 strains of bacteria were tested for small potted growth promoting effects.Since the colonies of strains 34,98 and 107 were not in the same shape and the growth between the strains had no effect,the two-two compound and the three-pack compound were carried out.The results of two times of pot experiments showed that the effects of strains 112,114 and TD1 on tobacco low temperature growth were mainly reflected in:1.The biomass of tobacco plants increased by 56.8%,71.5%,and 103.6%,respectively,compared with the control treatment.2.The maximum leaf length and width of tobacco plants were significantly different from those of the control.The maximum leaf length of tobacco was 3-5cm longer than the control tobacco,and the maximum leaf width was 2-3 cm wider than the control treatment.3.Strains 114 and TD1 have a promoting effect on tobacco root vigor,higher than the control treatment 200-300?g/g/h;4.The root length,surface area and volume of tobacco plants were significantly different from the control.The length of tobacco roots treated by these three strains increased by 432.1cm,472.2cm and 600.2cm respectively compared with the control.1.5-1.6 times.The root surface area of tobacco increased by 71.1cm2,70.5cm2,106.1cm2 compared with the control,which was 1.5-1.7 times of the control treatment,and the tobacco root volume increased by 0.9cm3,0.8cm3,1.5cm3 compared with the control;5.The soil urease activity has an effect of increasing,increasing 20-220 Ug/d/g;6.The germination rate of tobacco seeds has an effect of increasing at a normal temperature of 25? and a relatively low temperature of 18?.The germination rate is increased by 7.0%,7.0%,and 2.0%under normal temperature conditions,and the germination rate is increased by 8.3%and 7.9%,respectively.6.7%at low temperature.7.Molecular biological identification of strains 112,114 and TD1,which are Arthrobacter nicotinovorans,Bacillus muralis and Pseudomonas seleniipraecipitans,respectively.After 112,114,TD1 strains were subjected to secondary solid fermentation,the effect of large potted growth was verified.The effect of strain 112 on tobacco growth was mainly reflected in:1.The treatment of the 112 strain suspension of tobacco strain biomass strain increased the biomass by 36.6%compared with the control.2.The maximum leaf length,leaf width and stem circumference of the treated strains of 112 strains were higher than those of the control treatments of 12.9%,20.5%and 20.8%,respectively.The maximum leaf,stem diameter and tobacco plant height of the treated tobacco bio-organic fertilizer were 19.8%,17.9%and 77.1%higher than the control treatment,respectively.3.The root length of tobacco treated with strain 112 was 1.99 times of the control,the surface area of root was increased by 34.5%compared with the control,and the length of tobacco root treated by strain 112 was 1.6 times of the control.4.Treatment of strain 112 strains soil acid phosphatase,soil invertase and soil urease activity were 57.7%,48.4%and 32.9%higher than the control,respectively.Through the small pot and large potted verification test,strain No.112 was finally selected as the excellent strain which can be used for trial production in this study. |
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