Causal Factors and Control of the Necrotic Disorder of Berries in 'Muscat of Alexandria' Grape

葡萄浆果坏死病，在日本被称为“Shukuka-byo”，被认为是由于生理崩溃，但这种疾病的预防还不清楚。扫描电镜观察到，在受害浆果的花托和基部的筛分子和邻近薄壁细胞中有大量椭圆形至球形的颗粒，而在健康浆果中很少见到。颗粒多为Ca。0.5-1.0 μ m的直径，但有的较小，有的较大，有的表面光滑，有的表面粗糙。在接种有组织的培养基上的克隆中观察到0.2-2.0 μ m的粗糙颗粒，并且在所遭受的浆果的离心汁的沉淀部分中也观察到0.2-1.8 μ m的光滑颗粒。但透射电镜观察未发现微生物，仅发现一些0.2-1.0 μ m大小的圆形结构，无明显的膜和内部结构，推测是线粒体分解的产物。木质部汁液含有一些0.05- 0.2 μ m的生物体状颗粒，具有膜。MLO样菌落周围的组织经常产生的健康和/或遭受浆果和花托的阶段II成熟，但不是周围的组织从尖端培养的葡萄藤，种植在一个网状温室保护叶蝉，并没有表现出任何症状的坏死性疾病。通过移植，菌落不再生长，并且也不穿过抵靠组织放置的用于透析的纤维素膜生长。在液体培养基的12，000次离心（G）后，从沉淀级分中的颗粒中检测到核酸。除了对试管中无菌培养的插条进行基础处理的一个实例外，通过几次接种未阐明颗粒的致病性。

The necrotic disorder of grape berries, so called 'Shukuka-byo' in Japanese, has been considered due to physiological breakdown, but prevention of this disorder is yet obscure. Authors supposed that it should be a vascular disease infected by unknown organisms because of its first browning symptom appeared on vascular bundles, and preventive effectiveness of some antibiotic treatments.Numerous oval to spherical granules were observed in sieve elements and adjacent parenchymatous cells at receptacles and the basal portion of suffered berries, but rare in healthy berries through SEM. The granules were mostly ca. 0.5-1.0 mum of diameter, but some were smaller and others larger, and some were smooth in its surface but others rough. Rough granules of 0.2-2.0 mum were observed in the clonies on the medium inoculated with tissues, and smooth granules of 0.2-1.8 mum were also observed in the precipitated fraction of centrifuged juice of suffered berries. But we could not find any microorganisms through TEM, except some orbicular structures of 0.2-1.0 mum without clear membrane and interior, which were supposed to be broken down mitochondria. Xylem sap contained some organism-like granules of 0.05- 0.2 mum with membrane. MLO-like colonies were frequently produced around the tissues of healthy and/or suffered berries and receptacles on the StageII to maturation, but not around the tissues from the tip-cultured grapevines, which were planted in a netted greenhouse protected from leafhoppers and did not show any symptoms of the necrotic disorder. The colonies did not grow any more by its transplanting, and also did not grow through the cellulose films for dialysis laying against the tissues. Nucleic acids were detected from the granules in precipitate fraction after 12,000 centrifugation(G) of liquid culture medium. Pathogenisity of the granules was not elucidated by several inoculation, except a instance of basal treatment to the aseptic cultured cuttings in tubes.