- 期刊
萵苣褐斑病菌之半選擇性培養基
A Semiselective Medium for Detecting Acremonium lactucae, the Causal Agent of Lettuce Brown Spot
摘要
評估十四種碳素源與十八種氮素源對萵苣褐斑病菌Ａcremonium lactucae(AL-0818和AL-0724菌株）菌絲生長的影響，發現蔗糖及半乳糖兩種碳素源可顯促進菌絲的生長；至於氮素源中。則以酪蛋白有助於菌絲的生長。在培養基中，蔗糖和酪蛋白兩者的重量比在10與13.3時，分別有助於促進本菌AL－0724與AL－0818菌株發芽管的生長。比較十八種化學藥對本菌菌絲與發芽管生長的影響，發現貝芬替150ppm，褔多寧50ppm，鏈徽素200ppm和新徽素50ppm 藥劑的劑量均不具抑制本菌的功效。進一步，將蔗糖30g、酪蛋白3g、磷酸氫二鉀1g、硫酸鎂0.5g、氯化鉀0.5g、硫酸鐵0.01g、洋菜粉15g與蒸餾水1L均勻混合，經高溫高壓(121℃,15lb,30min)滅菌後，待溫度降至50Ｃ時，再逐一添加貝芬替150ppm、褔多寧50ppm 、鏈徽素200ppm 和新徽素50ppm 等藥劑配製成SC(Sucrose-Casein)半選擇性培養基。利SC半選擇性棓養基可以由一般栽培田或連作罹田土壤中偵測到本菌的存在，同時發現每克土中含有菌量數約0至4.3*103 cfu間。
並列摘要
Fourteen carbohydrates and eighteen nitrogenous compounds were evaluated for their effects on mycelial growth of two isolates, AL-0818 and AL-0724 of Acremonium lactucae, the causaI agent of brown , spot of lettuce. Among carbon sources, sucrose and galactose were more effective than other carbohydrates to enhance the growth of A. lactucae. As to nitrogenous compounds, casein was the most effective in stimulating growth of the pathogen isolates. The optimum ratio of sucrose and casein by weight was at 10 for AL-0724 or at 13.3 for AL-0818. Eighteen pesticides were respectively added into the basal medium Ca modified Czapek’s medium containing sucrose and casein, SC-medium) for indexing their suppressive effectiveness. Carbendazim at 150ppm and fluton1ani1 at 50ppm were not obvious to inhibit the pathogen. In advance, carbendazim, flutonlanil, streptomycin sulfate, and neomycin sulfate were selected to make up a formulation of the semiselective medium. The relationship between concentrations of the four pesticides and the germ-tube growth length of the pathogen was analyzed for determining the optimal formulation that favored the growth of A. lactucae and suppressed the contamination of undesired microorganisms. Finally, sucrose-casein semiselective medium (SC-semiselective medium) was composed of 30g sucrose, 3g casein, 19 K2HPO4, 0.5g K2Cl, 0.5g MgSO4 ‘7H20, 0.01lg FeSO4. 7H20, l5g agar, l50ppm carbendazim, 50ppm fIutonlanil, 200ppm streptomycin sulfate, 50ppm neomycin sulfate and IL distilled water. The results showed that se semiselective medium was able to accurately detect the pathogen from artificially and naturally infested sons. Generally, population density of the pathogen in naturally infested field soil was 04.3 *103 cfu/g soil by detection with se semiselective medium.