The effect of allelopathic rice seedling on rhizosphere soil microbes.

Soil microbe plays an important role in rice allelopathy in paddy. This study showed the effect of allelopathic rice variety PI321777 and non-allelopathic rice variety including “Liaojingjiu”and “Qingguan” on rhizosphere soil microbe in pot culture using spread-plating method and most probale number (MPN), respectively. The results demonstrated that allelopathic rice seedlings significantly affected the number of tested microbes in rhizosphere soil except actionmycete and ammonifying bacteria. The effect of allelopathic rice seedlings was much less than two non-allelopathic rice seedlings. Using t-test statistical analysis method, indicated that obvious difference of number from all microbes tested, except aerobic and anaerobic cellulose decomposing bacteria, occurred between allelopathic and non-allelopathic varieties. By comparison of two non-allelopathic rice varieties, only the number of fungi, actionmycete and aerobic nitrogen-fixing bacteria showed that there significant difference by t-test. Using single factor variance analysis showed that there were obvious difference from bacteria, actionmycete, fungi and aerobic nitrogen-fixing bacteria among the three rice varieties. Thus allelopathicrice seedlings could significantly reduce the populations of tested bacteria, actionmycete, fungi and aerobic nitrogen-fixing bacteria in rhizosphere soil. Allelopathic rice seedlings can release allelochemicals into the soil through root system and thus, the reduction in population of several microbes in rhizosphere soil was significantly correlated with the allelochemicals released by allelopathic rice root system. At present, there has been limited success in finding that the root exudates of the allelopathic rice, reduced the microbes in the paddy soil. Further research on chemical interactions between allelopathic rice variety and rhizosphere soil microbe is warranted.