采用生长速率法测定了29种植物乙醇提取物对山核桃干腐病和油茶炭疽病的抑制作用,筛选出抑菌效果较好的植物提取物,并对2种病原菌进行室内毒力测定,得出抑菌效果最优的植物提取物,使用光学显微镜观察植物提取物处理后的油茶炭疽病菌菌丝形态变化.结果显示,质量浓度为20 g/L时,丁香和牡丹提取物对2种病原菌抑制效果明显高于其他植物提取物,丁香提取物对山核桃干腐病和油茶炭疽病的抑菌率均为100%,牡丹提取物对山核桃干腐病和油茶炭疽病的抑菌率分别为(93.81±0.51)%和100%;室内毒力试验中,丁香和牡丹提取物对山核桃干腐病的抑菌中浓度值(CE50)分别为2.566和10.268 g/L,对油茶炭疽病的CE50值分别为1.005和10.988 g/L,由它们的抑菌中浓度值可知,相同质量浓度时,丁香对2种病原菌抑菌效果更好;显微镜观察发现,丁香提取物处理后油茶炭疽病菌菌丝出现菌丝隔的数目增多,细胞内原生质体减少,液泡增多等形态变化.%The inhibitory effects of ethanol extracts of 29 plants on Botryosphaeria dothidea and Colletotrichum gloeosporioides were determined by the growth rate method .Two plant extracts with good antifungal effect were screened out and the labora-tory toxicity of the two pathogens was tested to find out the better plant extract .After using the plant extract , the hyphae morphological changes of C.gloeosporioides were observed by optical microscopy .The inhibitory effects of Syzygium aromat-icum extract and Paeonia suffruticosa extract on the two pathogens were higher than that of other plant extracts at the con -centration of 20 g/L.The inhibitory rates of S.aromaticum extract on the two pathogens were both 100%, and the inhibito-ry rates of Paeonia suffruticosa extract on B.dothidea and C.gloeosporioides were, respectively, (93.81±0.51)%and 100%.In the study of laboratory toxicity , the CE50 of the extracts of Syzygium aromaticum and P.suffruticosa on B.do-thidea were 2.566 and 10.268 g/L, and on C.gloeosporoi ideswere 1.005 and 10.988 g/L, respectively .Compared with the values of CE 50 , at the same content , the inhibitory effect of S.aromaticum extract on the two pathogens was better .By mi-croscopic observation , there were changes in the morphology of hyphae of C.gloeosporioides, involving the increased num-ber of the septum of hyphae , the reduction of intracellular protoplast , and the increased vacuoles .
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