陕西省猕猴桃枝腐病研究初报

Study on a New Bacterial Twig Blight of Kiwi Tree

通过田间调查和室内研究相结合的方法,对近年来严重威胁陕西省猕猴桃生产的枝腐病进行了调查研究。田间调查结果表明,该病害主要在秋冬及早春发生,以危害当年的结果枝为主,引起枝条皮层腐烂及整枝枯死。全省各地发病程度在年份间有差异,严重时病株率和病枝率分别达98％和33％。利用常规的病原菌分离培养及接种方法证明该病害为细菌性病害,病原细菌的形态特点及生理生化特性研究结果表明,该病原菌为一种假单胞杆菌(Pseudomonas sp.),菌体短杆状,大小为1.0～3.0舯A×0.5～1.0 μm,极生单鞭毛。电镜观察发现,该病原细菌主要分布在枝干皮层细胞间隙,并且在发病后期的组织中易观察到由5～15个菌体集结成团的现象。

A new bacterial twig blight of kiwi tree was studied indoor and outdoor. The investigation revealed that the disease occurred in winter and early spring (Dec. -Mar. ) and caused rot and necrosis of twigs of bearing fruit. The diseased plants were as high as 98 % of total trees investigated and the diseased twigs were 33% of totals investigated in some orchard. The isolation and injection tests showed that the causation of kiwi twig blight was a kind of bacterium (Pseudomanas sp. ). The observation of transmission electronmicroscope and light microscope showed that the bacterial cell was short rods, pollar single flagellum. The single bacterial cell is 1. 0-3. 0 μm×0. 5-1. 0μm averagely. The bacterial cells were easily found extracellularly in the cortex of infected twigs. While the symptoms became very obvious and severe, the union of bacterial cells were easily found in the infected tissue. The field investigation showed that the disease occurrence was closely related with the climate such as lower temperature and the higher moisture as well as the status of trees.