丁基拉草施用於稻田對可培養性固氮細菌族群變化之影響

Effects of Butachlor Application on the Cultivable Nitrogen-Fixing Bacterial Community Variation in the Rice Paddy

陳玟瑾(Wen-Ching Chen) ； 顏瑞泓(Jui-Hung Yen) ； 王一雄(Yei-Shung Wang)

《臺中區農業改良場研究彙報》 114期 (2012/03) Pp. 1-10

https://doi.org/10.6956/BTDAIS.201203.0001

摘要

丁基拉草的施用可提升土壤固氮能力，為進一步了解丁基拉草的施用與土壤固氮細菌族群的關係，並篩選丁基拉草施用下之可培養固氮細菌，本研究施用10倍推薦量的丁基拉草於稻田土壤中，並於不同水稻生長時期測量土壤固氮活性的變化，之後分析可培養性固氮細菌數量的變化、分離篩選型態及16S rDNA編碼相異之可培養之土壤固氮細菌菌株。結果顯示，丁基拉草的施用造成土壤固氮量上升，尤其以孕穗期時之下層土壤其增加量最大。但於水稻成熟期時，上下層土壤固氮能力與對照組相較各增加7.20％及3.40％，顯示一次施用丁基拉草的情形下，土壤固氮能力可於水稻生育期間持續提升。分析土壤固氮細菌族群數量結果顯示，於孕穗期時（約為水稻移植後39天），固氮菌數量有顯著的上升。自控制組及處理組之稻田土壤中篩選出α-、β-及γ-變形菌門、厚壁菌門及放線菌門之可培養性固氮菌。比較兩組樣品所篩選出之菌株，發現無論在上層或下層土壤中，其族群組成亦有差異。因此，施用丁基拉草不但可以增加土壤游離性固氮菌的數量，並可改變其族群組成，兩者同時可能為造成土壤固氮能力上升的原因。

關鍵字

丁基拉草 ； 固氮細菌 ； 稻田

並列摘要

The previous research, reported that the application of butachlor raised soil nitrogen-fixing ability in paddy soils. To the further understanding of correlation between butachlor onto soil diazotrophic community and, to isolate the nitrogen-fixing bacteria under butachlor application, 10-fold butachlor was applied in the rice paddy. Afterward, the soil nitrogen-fixing ability, the population of nitrogen-fixing bacteria, and isolated cultivable diazotrophs based on different morphology and 16 rDNA sequences were measured at different rice growth stages. The results indicated that the application of butachlor could increase soil nitrogen-fixing ability in lower layer, especially at rice flowering stage. And at rice ripening stage, the 7.20% and 3.40% enhancement of soil nitrogen-fixing ability in the upper layer and lower layer, respectively. It was also indicated that only one time of butachlor application, the soil nitrogen-fixing ability increased throughout rice growth stages in the paddy soils. The population of diazotrophs increased significantly at rice booting stage around 39 days after transplanting. Moreover, α-, β- and γ- Proteobacteria, Firmicultes, and Actinobacteria were isolated both from control and treatment in the paddy soils. The composition of the diazotrophs was different in the two samples. Therefore, the application of butachlor will increase the soil nitrogen-fixing ability and changes the diazotrophic composition as well, which is contributed to the increase of soil nitrogen-fixing ability.

並列關鍵字

butachlor ； nitrogen-fixing bacteria ； rice paddy