Yan Zhinong, Reddy M S, Kloepper Joseph W
Department of Entomology and Plant Pathology, Auburn University, AL 36849-5409, USA.
Can J Microbiol. 2003 Jun;49(6):383-9. doi: 10.1139/w03-051.
Plant-growth-promoting rhizobacteria (PGPR) are used on crops most often as seed treatments; however, an alternative application method for transplanted vegetables is mixing PGPR into the soilless medium in which the transplants are grown. Studies were undertaken to compare root colonization and persistence of rifampicin-resistant mutants of PGPR strains Bacillus pumilus SE34 and Pseudomonas fluorescens 89B61, SE34r and 89B61r, on tomato as a function of application method. When the bacteria were incorporated into Promix soilless medium at log 6, 7, and 8 colony- forming units/g, populations of strain SE34r per gram of medium maintained the initial inoculum densities, while populations of 89B61r decreased approximately one to two orders of magnitude by 4 weeks after planting. The populations of each PGPR strain colonizing roots after application into the soilless medium showed a similar pattern at 6 weeks as that at 4 weeks after planting, with higher populations on the whole roots and lateral roots than on the taproots. Strain SE34r but not 89B61r moved upwards and colonized the phyllosphere when incorporated into the soilless medium. Following application as seed treatment, populations of SE34r were significantly higher on upper roots and on the taproot than were populations following application through the soilless medium. Conversely, populations were higher on lower roots and lateral roots following application through the soilless medium than were populations following application as seed treatment. While strain SE34 enhanced plant growth with application both to the medium and as seed treatment, the level of growth promotion was significantly greater with application in the soilless medium. The results indicate that PGPR can be successfully incorporated into soilless media in vegetable transplant production systems.
植物促生根际细菌（PGPR）最常作为种子处理剂用于农作物；然而，对于移栽蔬菜，另一种施用方法是将PGPR混入移栽蔬菜生长所用的无土培养基中。开展了多项研究，以比较PGPR菌株短小芽孢杆菌SE34和荧光假单胞菌89B61的耐利福平突变体SE34r和89B61r在番茄上的定殖情况及持久性，作为施用方法的函数。当将这些细菌以每克培养基6、7和8个菌落形成单位的对数浓度掺入ProMix无土培养基中时，每克培养基中SE34r菌株的数量维持了初始接种密度，而89B61r菌株的数量在种植后4周时下降了约一到两个数量级。在无土培养基中施用后定殖于根部的每种PGPR菌株数量，在种植后6周时呈现出与4周时相似的模式，整个根系和侧根上的数量高于主根。当掺入无土培养基中时，SE34r菌株而非89B61r菌株向上移动并定殖于叶际。作为种子处理施用后，SE34r菌株在上部根系和主根上的数量显著高于通过无土培养基施用后的数量。相反，通过无土培养基施用后，下部根系和侧根上的数量高于作为种子处理施用后的数量。虽然SE34菌株在施用于培养基和作为种子处理时均能促进植物生长，但在无土培养基中施用时的促生长水平显著更高。结果表明，PGPR可以成功地掺入蔬菜移栽生产系统的无土培养基中。
