番茄根际微生物种群动态变化及多样性

Variation and Diversity of Microbial Populations in the Rhizosphere Soil of Tomato Plants

采用盆栽试验的方法对番茄根际主要微生物种群在不同生育期的动态变化进行了跟踪研究。结果表明,在番茄整个生育期内,可培养细菌数量在初花期和初果期时最多;放线菌数量从苗期到末期逐渐减少;真菌数量逐渐增多。番茄对细菌根际效应明显。DGGE图谱显示不同生育期番茄根际均具有较高的细菌多样性。根际细菌种类和数量在初花期发生较为显著的变化,初果期根际群落多样性指数(H)和物种丰度(S)值都达到最高,微生物最丰富,是筛选拮抗菌的较好时期。

The total amount of colony forming units（CFU） of bacteria,fungi and actinomycetes in the rhizosphere and surrounding soils were investigated at four different growing stages of tomato plants using traditional plate-counting method.The amount of bacteria reached its peak value at the blossoming stage and the fruiting stage.From seedling stage to late period,actinomycete number decreased gradually with time,but fungi increased.For bacteria,the rhizosphere effect of tomato plant（R/S） was the highest at the early blossoming stage and the early fruiting stage.The variation and diversity of microbial populations in the rhizosphere soil of tomato plants were also studied using cultivation-independent analysis.DGGE profile indicated high diversity of microbial populations in the rhizosphere soil at different growth stages.The bacterial species kept stable but the population of particular species changed in different patterns.Manifest change in rhizosphere bacterial species and populations occurred at the early blossoming stage,and the most abundant bacterial species was observed at the early fruiting stage.This investigation successfully revealed the community features of the culturable and unculturable microbes in the rhizosphere soil of tomato plants,and indicated that the most abundant bacterial species occurred at the fruiting stage,suggesting this stage a suitable period for screening antagonistic bacteria.