【作者】 刘亚亚；

【导师】 陈垣；

【作者基本信息】 甘肃农业大学 ， 药用植物资源与利用， 2010， 硕士

【摘要】 本文对甘肃礼县掌叶大黄(Rheum palmatum L.)根腐病病原物进行了分离鉴定,并对分离得到的主要病原菌进行生物学特性研究和防治药剂筛选。研究结果归纳如下：1.掌叶大黄根腐病主要致病菌分别为粉红单端孢霉(Thichothecium roseum(Bull.) Link.)、尖孢镰刀菌(F.oxysporum schlecht.)和立枯丝核菌(Rhizotonia solani kUhu.)。刺伤大黄幼根接种致病菌后,根腐病发病率均较无刺伤接种显著提高,掌叶大黄根腐病病原菌主要是通过伤口进行侵染的,在生产过程中,应尽量避免对其根部造成伤口。2.粉红单端孢霉最适碳源为麦芽糖；最适氮源为硝酸钠；紫外灯照射2h后黑暗培养促进菌丝生长,持续光照有助于产孢；最适生长pH为6；最适生长温度为25-30℃。尖孢镰刀菌最适菌丝生长的碳源为蔗糖,而葡萄糖最利于产孢；硝酸钠可促进菌丝生长,但硝酸铵较能促进其产孢；持续黑暗促进菌丝生长,紫外灯照射2h后黑暗培养可促进其产孢；最适菌丝生长pH为6,最适产孢pH为8；最适生长温度为25-30℃。立枯丝核菌最适碳源为可溶性淀粉；硝酸钠可促进菌丝生长,但硝酸铵可促进其产孢；光暗交替抑制菌丝生长；最适生长pH为5；最适生长温度为20-25℃。3.掌叶大黄根腐病病原菌经不同高温处理15 min后,再置25℃黑暗条件下培养,对耐高温性表现显著的差异。粉红单端孢霉(T.roseum(Bull.) Link.)在培养3-7 d时生长抑制起始温度分别为47、60、68、67和68℃,LTso分别为69、79、80、83和83℃,菌丝生长最大抑制速率分别为0.0080、0.0067、0.0071、0.0066和0.0065 cm/℃；尖孢镰刀菌(F.oxysporum schlecht.)在培养3-7d时生长抑制起始温度分别为43、51、59、61和77℃,LTso分别为61、73、82、86和92℃,菌丝生长最大抑制速率分别为0.0178、0.0162、0.0149、0.0149和0.0120 cm/℃。两种病原物的生长抑制起始温度和LTso均随培养时间的增加呈递增趋势,而生长最大抑制速率却随培养时间的增加呈递减趋势,说明病原物在受到高温胁迫后随着时间的延长,对温度的耐受力提高。立枯丝核菌(Rhizotonia solani kUhu.)对温度较敏感,其致死温度和时间为50℃下处理15 min。4.12种供试杀菌剂中,对3种病原菌抑菌效果较好的有4种,分别是治高40%可湿性粉剂、50%多菌灵可湿性粉剂、强生和代森锰锌70%可湿性粉剂,这4种药剂对尖孢镰刀菌的有效中浓度(EC50)分别为17.74、27.29、236.84和853.99 mg/L,对尖孢镰刀菌EC50分别为56.92、1.34E-12、400.53和2155.04 mg/L,对立枯丝核菌以治高效果最为突出,多菌灵其次,代森锰锌70%可湿性粉剂最差。更多还原

【Abstract】 In this article, with Chinese traditional medical herb Rheum palmatum L.in Lixian county of Gansu Province.as material, Isolation and identification of the pathogens causing Rheum palmatum L. root rot, Studies on biological characteristics of the pathogen of the Rheum palmatum L. Root rot and Fungicide screen assays in lab were studied. The main results are as follows:1. The chief pathogens causing Rheum palmatum L. root rot were Thichothecium roseum (Bull.) Link., F. oxysporum schlecht., Rhizotonia solani kUhu.. The incidence of the root rot after inoculation pathogens by gore radicles were significantly higher than that by non-gore radicles. All above reveals that the wound is helpful for the root rot pathogens to infect in the plants. It suggests that the transplant and cultivation should be careful to keep the plant integrality preventing the wound.2. As T.roseum (Bull.) Link, the best carbon resources was Maltose; The best nitrogen resources was carbamide and potassium nitrate; Ultraviolet irradiation 2 houre under dark condition could promote mycelia growth, but it could restrain sporulation, light could promote mycelia for sporulation; the optimal pH was 6;The optimal temperature was 25-30℃. As F.oxysporum schlecht., sucrose was the best medium for pathogen growth, but glucose was the best medium for sporulation; sodium nitrate was the best medium for pathogen growth, but ammonium nilrate was the best medium for sporulation; Whole darkness promote mycelia growth, but ultraviolet irradiation 2 houre under dark condition could promote sporulation; The optimal pH was 6 for pathogen growth,and the optimal pH was 8 for sporulation; The optimal temperature was 25-30℃.As R.solani kUhu. the best carbon resources was Tragantine;The best nitrogen resources was ammonium nitrate; The alternation of darkness and light could restrain mycelia growth, The optimal pH was 5;The optimal temperature was 20-25℃.3. The linear result based on Logistic equation fitting mycelium growth with treatment temperatures shouwed that the pathogens causing R. palmatum L. root rot by High temperature processed 15 min,Cultivated in the condition of 25℃,No light. As T.roseum (Bull.) Link., The Growth inhibition starting temperatures were 47,60,68,67 and 68℃, LT50 were 69,79,80,83 and 83℃,Maximum inhibition rate of mycelium growth were 0.0178,0.0162,0.0149,0.0149 and 0.0120 cm/℃; As F. oxysporum schlecht., The Growth inhibition starting temperatures were 43,51,59,61 and 77℃, LT50 were 61,73,82,86 and 92℃, Maximum inhibition rate of mycelium growth were 0.0178,0.0162,0.0149,0.0149 and 0.0120 cm/℃. As R. solani kUhu.,Was sensitivity to temperatures, The Lethal temperature and time were 50℃and 15 min.4. Of 12 kinds of fungicides, there were 4 fungicides such as Zhigao, carbendazim, qiangsheng and Mancozeb had inhibition effect on the pathogens causing R. palmatum L.root rot. Their EC50 were 17.74,7.29,236.84 and 853.99 mg/L respectively to T. roseum (Bull.) Link. Their EC50 to F. oxysporum schlecht. were 56.92,1.34E-12,400.53 and 2155.04 mg/L respectively. Zhigao and carbendazim had the best and better control effects on R. solani kUhu, while the effect of Mancozeb followed.更多还原