Abstract: In order to improve the decomposition efficiency of straw returning to the field, an actinomycete strain with strong cellulose degradability was isolated by using CMC-Na medium, Congo red medium and filter paper plate medium. At the same time, the seed germination method was used to study the growth-promoting effect of the strain on soybean [Glycine max （Linn.） Merr.] seeds. The activities of POD, CAT and SOD and the content of MDA in soybean seeds were also studied. The results showed that the isolated strain had a strong ability to decompose cellulose, and the germination rate and antioxidant enzyme activity of soybean seeds were changed after treated with different concentrations of cellulose-degrading bacteria fermentation broth. When the concentration of fermentation broth was 100.0%, the germination rate of soybean seeds reached the highest, was 74.53%, increasing by 21.96 percent compared with the control（Mendal's medium without bacterial fluid）; the activity of CAT and SOD was the strongest, which increased by 291.45% and 106.64% respectively compared with the control; and the POD activity was 25.6 U/（mL·min）, 101.96% higher than that of the control, but it was 14.65% lower than that of the pure water culture. The content of MDA was the lowest at 16.7%, which was 21.37% lower than that of control. It was preliminarily confirmed that the fermentation broth of cellulose-degrading bacteria contained substances which could promote the germination of soybean seeds and increase the activities of antioxidant enzymes, as well as protective membrane components.

Key words: cellulose-degrading actinomycetes, soybean[Glycine max （Linn.） Merr.], seed germination