| 摘要: | 立枯絲核菌(Rhizoctonia solani Kuhn AG-4)為臺灣生產百合種球重要限制因子之一；由各地土壤及百合植株鎖分離得到之325株細菌與8株真菌，經對峙、共同培養即在鱗片上競爭佔據等之篩選檢定，挑選出六株細菌菌株，進行六次溫室生物檢定，確定Bacillus megaterium S26及#18兩株菌株均可顯著地(P=0.05)減少百合植株莖部的壞疽及倒伏，而百合種球之鮮重及乾重亦較未處理對照組為佳。此外，在溫室中，將低濃度的拮抗菌(104CFU/ml)和62.5ppm殺菌劑待克利(difenoconazole)混合施用，所獲得之防治效果，較單獨施用125ppm待克利為佳，且和健康對照組無顯著性(P=0.05)差異；但在田間施用拮抗菌的防治效果不彰。B.megaterium S26及#18對病原菌的生長具有明顯的抑制效果，該拮抗菌並且可附著於R.solani菌絲上，引起菌絲變形、膨大和凹陷，甚至會造成菌絲崩潰溶解的現象。B.megaterium#18的無菌濾液對R.solani亦有相同的抑制效果。
Lily root rot caused by Rhizoctonia solani AG-4 is one of the limiting factors for producing healthy lily bulbs in Taiwan. A total of 325 isolates of bacteria and 8 isolates of fungi were obtained from the rhizosphere soil and tissues of lilies. Six isolates of bacteria were able to inhibit the mycelial growth of R. solani on cultural media and had better competitive saprophytic ability to colonize on lily bulbs. Among them, Bacillus megaterium S26 and #18 were proved to have the ability in reducing significantly (P=0.05) damping-off of lily seedlings. Besides, the antagonists increased significantly (P=0.05) the fresh and dry weights of lilies. In greenhouse, lily bulbs treated with the mixture solution of low concentration of B. megaterium S26 or #18 (104 CFU/ml) and difenoconazole (62.5 ppm) grew significantly (P=0.05) better than bulbs treated with 125ppm difenoconazole only, but not significantly different from those of the healthy controls. However, the effects of control1ing R. solani by the same antagonists in the fields were not as obvious as those tests in greenhouse. One percentage of cultural filtrates of B. megaterium #18, which ,was cultured in PDB for 6 days, was effective to inhibit the mycelial growth of R. solani. Meanwhile, B. megateriulll S26 could colonize on the hyphae of R. solani and caused malformation and lysis of the infected hyphae eventully. |
