摘要
用烟草赤星病菌的6个菌株测定了病菌在低温保存、连续培养和连续接种过程中致病力的表现,病菌在1—4℃下保存4年后,侵入寄主的能力不变,引起病斑扩展的能力略有减弱。连续23代继代培养的结果表明,致病力表现稳定,菌株TBA28的侵染能力(接种幼苗后的发病率)和引起病斑扩展的能力(病情指数)分别稳定在100％和60—80之间,另外5个菌株的这两项值分别在60—100％和20—40之间变化。连续11代继代接种的结果也表明了类似趋势,菌株TBA28一直表现出最强的致病力,两项测定值分别为近100％和40左右,其余菌株均保持较弱的致病力。这些结果表明,病菌致病力经低温保存虽有减弱,经人工培养和接种可恢复到原有的水平,而连续培养或连续接种不引起致病力的减弱或增强。
Six strains of Alternaria alternata were tested for their pathogenicity variations during being cold-preserved, successively cultured and successively inoculated to tobacco seedlings. After the pathogen had been cold-preserved for 4 years, it showed no reduction of host-invading capability and slight weakening of brown spot-expanding ability. During successive culture, the pathogenicity of the pathogen was principally stable indicated by certain ranges of invading ability (IA) and brown spot-expanding ability (EA) to the plant seedlings. The strongest virulent strain TBA28 gave consistantly 100% of IA and 60—80 of EA. Other 5 strains gave 60—100% of IA and 20—40 of EA. The similar tendency was also found in successive inoculation, in which about 100% of IA and 40 of EA were shown by the strain TBA28 and more lower tested values of IA and EA by other 5 strains. These results suggested that neither reduction was caused by successive coulture nor enhancement was induced by successive inoculation for pathogenicity of tobacco brown spot pathogen.
出处
《山东科学》
CAS
1993年第2期18-21,29,共5页
Shandong Science
关键词
烟草
赤星病菌
致病力
变异
tobacco brown spot pathogen
pathogenicity
variation
