| Lettuce root growth promoting bacteria screening and determination of growth promoting properties |
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| DOI：10.7606/j.issn.1000-7601.2020.03.17 |
| Key Words: lettuce plant growth\|promoting rhizobacteria phosphorus\|dissolving bacteria nitrogen\|fixing bacteria plant growth hormone (IAA) |
| Author Name | Affiliation | | HAN Dongrong | Key Laboratory of Grassland Ecosystem, Pratacultural College, Gansu Agricultural University, Lanzhou, Gansu 730070, China | | HOU Dong | Vegetable Research Institute, Gansu Academy of Agricultural Sciences, Lanzhou, Gansu 730070, China | | YAO Tuo | Key Laboratory of Grassland Ecosystem, Pratacultural College, Gansu Agricultural University, Lanzhou, Gansu 730070, China | | LAN Xiaojun | Key Laboratory of Grassland Ecosystem, Pratacultural College, Gansu Agricultural University, Lanzhou, Gansu 730070, China | | ZHU Ruiting | Key Laboratory of Grassland Ecosystem, Pratacultural College, Gansu Agricultural University, Lanzhou, Gansu 730070, China |
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| Abstract: |
| In order to obtain excellent strains of lettuce (Lactuca sativa) root growth\|promoting bacteria and provide excellent strains for the subsequent development of microbial inoculants (bacterial fertilizers),we took the root system of lettuce as the research object and used selective incubation culture medium to separate and screen the ability of lettuce roots in dissolving organic phosphorus (P), inorganic phosphate solubilizing bacteria, and nitrogen(N)\|fixing bacteria, and determine their ability to dissolve P, N fixation, plant growth hormone secretion, and antagonistic ability against plant pathogenic.We also tried to identify excellent strainsby 16S rDNA molecular biology technology. The results shown that 25 strains of P\|dissolving strains were isolated from the roots of lettuce, and their ability to dissolve inorganic P was 60.83~290.66 μg·mL-1 (the highest amount of P in PGBA2 was 290.66 μg·mL-1);The ability to dissolve organic P was generally low, ranging from 8.12 to 71.87 μg·mL-1. The 20 strains of N-fixing strains were isolated, and the nitrogenase activity was 8.37~371.54 nmol·h-1·mL-1 (the most active nitrogenase activity of GNB6 was 371.54 nmol·h-1·mL-1). Fourteen strains of secreted plant growth hormone (IAA) strains were isolated and screened, and the secretion amount was 0.78~5.29 μg·mL-1 (MGBD1 had the strongest ability to secrete IAA at 5.29 μg·mL-1). The strains MGNB4, MGBC3, and PGBA2 had antibacterial activity against Fusarium oxysporum, and the inhibition rate was over 50%. After the molecular biological identification of 9 excellent PGPR strains, the strains MGBC2, MGBC3, and PGBA2 were Acinetobacter calcoaceticus; the strains MGNB3 and MGNB4 were Enterobacter huaxiensis; the strain MGBD1 was Pseudomonas brassicacearum; the strain GND5 was Bacillus subtilis; the strain GNA6 was Microbacterium aerolatum, and the strain GNB6 was Rhizobium radiobacter. The excellent root\|growth promoting bacteria selected in this study can provide excellent strains for the future development of lettuce microbial fertilizer,also enriched the PGPR strain resource bank. |
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