在江苏省句容县从日本引进的三叶芹(Cryptotaenia canadensis var japonica)蔬菜作物上,观察到一种丛枝病的发生。病害一般在春季返青时开始表现症状。病株分枝增多,形成典型丛枝症状,同时全株矮缩、黄化.叶片变小,花序分化不正常。田间调查表明,施肥水平高的田块发病较轻,肥料不足的发病重;一般田块发病率在15％左右,重的达30％以上,严重影响三叶芹的产量和品质。 取病株幼茎或叶片主脉制备电镜样品。用3％戊二醛和1％锇酸双固定;乙醇梯度脱水;无水丙酮置换两次,用1:1丙酮和Epon812浸透,最后用纯Epon812包埋,60℃聚合,超薄切片,切片经饱和醋酸双 A bushwort disease was observed on a vegetable crop of Cryptotaenia canadensis var. Japonica introduced from Japan in Jurong county, Jiangsu province. Diseases usually start to show symptoms when they turn green in spring. Branches of diseased plants increased, forming typical symptoms of bushy branches, while the whole plant dwarfed and yellowed, the leaves became smaller and the inflorescences were not well differentiated. Field surveys showed that the field with high fertilization level had less incidence and the shortage of fertilizer was more serious. The incidence rate of common field was about 15% and the weight was more than 30%, seriously affecting the yield and quality of the three-leaf celery. Take sick young stems or leaves of the main vein preparation electron microscopy samples. Fixed with 3% glutaraldehyde and 1% osmium tetroxide; dehydrated in ethanol; dehydrated in anhydrous acetone twice; impregnated with 1: 1 acetone and Epon 812; finally embedded in pure Epon812; polymerized at 60 ° C; Double saturated with acetic acid