从化感水稻根际土壤中筛选抑草细菌的研究

Screening the Bacteria Herbicide from the Rhizosphere Soils of Allelopathic Rice

从化感水稻PI312777根际土壤中筛选具有抑草作用的细菌,为开发抑草微生物资源提供科学依据。以稀释涂布平板法筛选菌株,以莴苣、稗草为受体,实验室生物测试和盆栽试验相结合,确定候选菌株的抑草活性。实验室生物测试结果表明,有2个菌株Z1和Z2的发酵液对莴苣具有强抑制作用,且对稗草根长的抑制率为50%~60%,株高的抑制率为40%~50%。盆栽试验结果表明,Z1和Z2的发酵液对稗草根长的抑制率分别为28.1%和27.0%,株高的抑制率分别为8.85%和4.48%。菌株发酵液对3种水稻的根长有促进作用,对株高没有影响或小的抑制作用（抑制率3%）。结果表明水稻化感抑草作用与根际微生物有关,暗示从化感水稻根际土壤中筛选抑草细菌是一个可行的思路。

The bacteria were screened from the rhizosphere soil of allelopathic rice PI312777 for weed suppression, which could provide a scientific basis for the development of herbicides source. The plate dilution method was used to isolate microorganisms, and a laboratory bioassay and a soil pot test with lettuce and barnyard grass were used as the receptors to evaluate the bioactivity of culture filtrate of the candidate strains. Laboratory bioassay proved that fermentation broths of two candidate strains Z 1 and Z2 had the strongest inhibition on lettuce growth. And the maximum inhibitory rates of the fermentation broths on root length and plant height of barnyard grass were about 50%-60% and 40%-50%, respectively. In soil pot test, the inhibitory rates of the fermentation broths Z1 and Z2 were 28.1% and 27.0%, respectively on root length of barnyard grass, and 8.85% and 4.48%, respectively on plant height of barnyard grass. The fermentation broths had stimulative effect on root length of 3 rice accessions and no negative effect or little inhibition （inhibitory rate of 3% ）. These results showed that rice allelopathy was correlated to their microorganisms of the rhizosphere soil and suggested that screening bacteria herbicides from the rhizosphere soils of allelopathic rice accessions would be a feasible approach.