Experimental Transmission of Citrus Blight in South Africa
Experimental Transmission of Citrus Blight in South Africa
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南非柑橘枯萎病的实验传播
DOI：
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发表时间：
1991
期刊：
影响因子：
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通讯作者：
R. Lee
中科院分区：
文献类型：
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作者：
L. Marais;R. Lee
将12棵健康的4年生瓦伦西亚甜橙子树移植到同一品种的15年生果园中，其中柑橘枯萎病发生率很高。将树成对种植在受枯萎病影响的树的北侧和南侧。将一对健康受体树之一的几个根接近嫁接到相邻枯萎供体树的根上。23个月后，6棵受体树中有4棵表现出典型的枯萎病视觉症状。嫁接后三年，症状受体树木减少了水分吸收，显着较高浓度的锌在树干韧皮部和无定形插头在树干木质部的船只。六棵对照树都没有出现这些典型的枯萎病症状。索引词。根移植1979年，Da Graca和货车Vuuren（4）首次报道了南非共和国类似柑橘枯萎病的衰退。1982年，从德兰士瓦东部和北方的几个柑橘产区收到了这种严重衰退的报告，因此在南非和斯威士兰的主要柑橘产区进行了调查，以核实柑橘枯萎病的存在并确定其分布（7，10，11）。正是在这次调查中，开发了注射器注射技术作为柑橘枯萎病的快速诊断试验（8）。也是在1982年，佛罗里达阿尔弗雷德湖的CREC的研究人员和南非的研究人员开始合作研究枯萎病。为了进一步证实南非的柑橘枯萎病实际上与佛罗里达的柑橘枯萎病相同，并获得更多关于枯萎病生物体的病原学数据，决定在枯萎病严重的地区进行传播实验。这些实验是基于Tucker等人（15）和Lee等人（9）进行的实验，他们证明了受枯萎病影响的树木根部存在感染因子。所有以前的研究，包括霍普金斯最近的工作（5），一直无法人工复制所有已知的症状，疾病的结果树。本文报道了一个传递试验的结果，即将表面健康的4年生树的根近接于15年生枯萎病树上
Twelve healthy 4-yr-old Valencia sweet orange trees on Troyer citrange rootstock were transplanted to a 15-yr-old orchard of the same variety in which a high incidence of citrus blight occurred. The trees were planted in pairs on the north and south sides of a blight affected tree. Several roots of one of the pair of healthy receptor trees were approach-grafted to roots of the adjacent blighted donor trees. After 23 months, four of six of the receptor trees exhibited typical visual symptoms of blight. Three years after grafting, symptomatic receptor trees had reduced water uptake, significantly higher concentrations of zinc in trunk phloem and amorphous plugs in vessels of the trunk xylem. None of the six control trees developed these typical blight symptoms. Index words. root grafts. The first description of a decline resembling citrus blight in the Republic of South Africa was reported in 1979 by Da Graca and Van Vuuren (4). In 1982 reports of severe cases of this type of decline were received from several Eastern and Northern Transvaal citrus producing areas, consequently a survey was conducted in the major citrus producing areas of South Africa and Swaziland to verify the presence of citrus blight and to determine its distribution (7, 10, 11). I t was during this survey that the syringe injection technique as a rapid diagnostic test for citrus blight was developed (8). It was also in 1982 that cooperative blight research between researchers at CREC, Lake Alfred, Florida and researchers in South Africa commenced. To further verify that citrus blight in South Africa was in fact identical to that in Florida and to gain more etiological data on the blight organism it was decided to conduct transmission experiments in areas where blight was severe. These experiments were based on those conducted by Tucker, et al. (15) and Lee, et al. (9) who demonstrated the presence of an infectious agent in the roots of blight affected trees. All previous research, including most recent work by Hopkins (5), has been unable to artificially reproduce all of the known symptoms of the disease in bearing trees. This paper reports on the results obtained in one of the transmission experiments in which roots of apparently healthy 4-yr-old trees were approach grafted to 15-yr-old blighted