苜蓿种带真菌及其致病性测定

Seed borne fungi of lucerne and their pathogenicity to lucerne seed and seedling

对来自我国新疆、内蒙古、吉林、陕西、甘肃、宁夏、山东、黑龙江、山西、河北和江苏等 11个省 (自治区 )苜蓿产区的 30个审定登记品种的 38个苜蓿种子样品进行了系统的种带真菌检测研究 ;测定了 2 1种 2 5个真菌分离物对苜蓿幼苗根组织的入侵性及 19种真菌对苜蓿种子萌发和幼苗生长的影响。结果表明 ,种样带菌率为 0 .75%～ 10 0 % ;共鉴定出 36属 4 0种种带真菌 ,检出率为 0 .0 1%～ 36 .8% ,其中青霉、细交链孢、粉红单端孢、黑曲霉、多主枝孢和黄曲霉为苜蓿常见的种带真菌 ,且对种子或幼苗造成不同程度的危害 ;尖镰孢、燕麦镰孢、不全壳二孢、立枯丝核菌、根腐离蠕孢、色二孢、细交链孢和多主枝孢是苜蓿的种带病原真菌 ,其中尖镰孢使种子全部烂死、无一萌发 ;所有参试的 19种真菌使苜蓿幼苗腐烂的严重度显著地(P<0 .5)

Thirty eight seed samples belonging to 30 registered lucerne varieties were collected and tested for seed borne fungi. The seed samples were produced in 11 provinces(Automonous Regions) in China, which included Xinjiang, Inner Mongolia, Jilin, Shaanxi, Gansu, Ningxia, Shandong, Heilongjiang, Shanxi, Hebei and Jiangsu. Invasiveness of 25 isolates of 21 fungal species from seed to seedling root tissue and effects of 19 fungal species on seed germination and seedling growth of lucerne were tested. Percentage frequency of fungi isolated from each seed sample was 0.75% to 100%, and 40 fungal species of 36 genera were identified. Among them, Penicillium spp., Alternaria alternata (Fr.) Keiss., Trichothecium roseum(Bull.) Link, Aspergillus niger Tiegh., Cladosporium herbarum(Pers.) Link and A.flavus Link were isolated most frequently and caused damage to seed and seeling in some extent in invasiveness test. The pathogenicity tests showed that Fusarium oxysporum Schlecht., F.avenaceum (Fr.) Sacc., Ascochyta imperfecta Peck, Rhizoctonia solani Kuhn, Bipolaris sorokiniana (Sacc. et Sorok..) Shoem, Diplodia sp., Alt. alternata and Cl.herbarum were the seed borne pathogeic fungi of lucerne. Compared to uninoculated control, all 19 fungal species tested reduced lucerne seed germination and increased root rot index significantly (P<0.05), whereas F.oxysporum killed all seeds tested.