苹果粗皮病两种技干症状的观察与研究

通过盆栽试验及田间调查发现，生理粗皮病（Internal bark necrosis）是由于韧皮部中部分木质化组织的内部发生增生坏死而使得外表隆起，病瘤的发生部位不定。轮纹病的瘤状突起是由于病菌侵染后在皮下扩增，形成了索状菌丝体结构，多数在皮孔部位发生。病枝离体后，生理粗皮病的病瘤不扩展，而轮纹病的病瘤很快扩展为褐斑瘤。生理粗皮病病树的新梢叶片出现缺铁症状，轮纺病的不出现。从各地的调查结果看，当前所发生的粗皮病主要是轮纹病，生理性粗皮病非常少见。

OBSERVATION AND STUDY ON TWO TYPES OF ROUGH BARK SYMPTOMS ON APPLE STEM

Symptoms of rough bark on apple stem were studied.Results show that the proliferation and necrosis of certain xylary tissues in the bark phloem cause the warts of internal bark necrosis (IBN) on apple stem.The occurrence position of IBN on the surface of stem is not fixed.The infection of the fungus and the formation of rope-like mycelium under the cuticle cause the warts of ring rot ( Botryospharia berengriana f.sp. piricola ).The warts often occurr on the lenticels.The warts of IBN do not expand when taken off the tree.However,in vitro warts of ring rot soon expand to large dark brown lesions.A deficiency symptom of iron appears on the shoot of IBN occurred trees other than the ring rot-occurred trees.It is suggested that most of the rough bark symptoms on apple trees are caused by ring rot according to the results of the investigation on the cause of rough bark apple in Liaoning province.IBN is scarce in Liaoning province.