抑草圈种植下水稻和稗草根际土壤酶活性和微生物群落变化

Soil enzyme activity and microbial community in rhizosphere of rice and barnyard grass co-cultured by inhibitory-circle method

采用稻/稗共培抑草圈土壤盆栽法研究化感水稻PI312777和非化感水稻Lemont与稗草共培下水稻化感潜力、根际土壤酶活性及土壤微生物群落的变化.结果表明,化感水稻PI312777显著抑制12 cm处稗草的生长,PI312777根际土壤过氧化物酶和蔗糖酶活性高于Lemont,稗草根际土壤的蔗糖酶、脲酶活性降低;PI312777根际土壤微生物对氨基酸类、糖类和酚酸类碳源的利用程度显著高于Lemont,稗草根际土壤微生物对氨基酸类、多聚物类、酚酸类、羧酸类的利用率显著下降.相关性分析表明,水稻对稗草的抑制率与水稻根际土壤的过氧化物酶和蔗糖酶活性显著负相关,与水稻根际土壤微生物对羧酸类、多聚物类和酚酸类碳源的利用率相关,与稗草根际土壤微生物对氨基酸类和酚酸类碳源的利用率相关.水稻对稗草的化感作用与供体和受体植株根际的土壤酶活性和土壤微生物种群变化密切相关,对水稻化感作用的微生态起重要的调节作用.

Allelopathic potential, rhizosphere soil enzyme activity and soil microbial community of co-cultured rice seedlings(allelopathic rice PI312777 and non-allelopathic rice Lemont) and barnyard grass were studied in potted soil by inhibitory-circle method. The results showed that allelopathic rice PI312777 significantly inhibited the growth of barnyard grass grown at a distance of 12 cm. The activities of peroxidase and sucrase in the rhizosphere soil of PI312777 were higher than those of Lemont, and the activities of sucrase and urease in the rhizosphere soil of barnyard grass were reduced. Utilizations of amino acids, sugars and phenolic acids by microorganisms from the rhizosphere soil of PI312777 were significantly higher than those from Lemont, but the utilizations of amino acids, polymers, phenolic acids and carboxylic acids by microorganisms from the rhizosphere soil of barnyard grass were decreased at a distance of 12 cm from PI312777. The inhibition effect of rice on barnyard grass was significantly negatively correlated with the activities of peroxidase and sucrase in rice rhizosphere soil, and correlated with the microbial utilizations of carboxylic acids, polymers and phenolic acids in rice rhizosphere soil. Rice allelopathic potential was also correlated with the utilization of amines and phenolic acids by microorganism from the rhizosphere soil of barnyard grass. To summarize, rice allelopathy was closely related to the enzyme activities and microbial activities in the rhizosphere soils of rice seedlings and barnyard grass, which exerted some certain regulatory effect on soil micro-ecology.