Alves Marcelo de Carvalho, Pozza Edson Ampélio
Soil and Rural Engineering Department, Federal University of Mato Grosso, Cuiabá, Mato Grosso, Brazil.
Microsc Res Tech. 2009 Jul;72(7):482-8. doi: 10.1002/jemt.20695.
The aim of this study was to test the standard scanning electron microscopy (SEM) as a potential alternative to study seed-borne fungi in seeds, by two different conditions of blotter test and water restriction treatment. In the blotter test, seeds were subjected to conditions that enabled pathogen growth and expression, whereas the water restriction method consisted in preventing seed germination during the incubation period, resulting in the artificial inoculation of fungi. In the first condition, seeds of common bean (Phaseolus vulgaris L.), maize (Zea mays L.), and cotton (Gossypium hirsutum L.) were submitted to the standard blotter test and then prepared and observed with SEM. In the second condition, seeds of cotton (G. hirsutum), soybean (Glycine max L.), and common bean (P. vulgaris L.) were, respectively, inoculated with Colletotrichum gossypii var. cephalosporioides, Colletotrichum truncatum, and Colletotrichum lindemuthianum by the water restriction technique, followed by preparation and observation with SEM. The standard SEM methodology was adopted to prepare the specimens. Considering the seeds submitted to the blotter test, it was possible to identify Fusarium sp. on maize, C. gossypii var. cephalosporioides, and Fusarium oxysporum on cotton, Aspergillus flavus, Penicillium sp., Rhizopus sp., and Mucor sp. on common bean. Structures of C. gossypii var. cephalosporioides, C. truncatum, and C. lindemuthianum were observed in the surface of inoculated seeds.
本研究的目的是通过两种不同条件的吸水纸检验和水分限制处理，测试标准扫描电子显微镜（SEM）作为研究种子中种传真菌的一种潜在替代方法。在吸水纸检验中，种子处于能使病原体生长和表达的条件下，而水分限制方法则是在培养期阻止种子萌发，从而实现真菌的人工接种。在第一种条件下，将菜豆（Phaseolus vulgaris L.）、玉米（Zea mays L.）和棉花（Gossypium hirsutum L.）的种子进行标准吸水纸检验，然后制备并通过扫描电子显微镜观察。在第二种条件下，分别通过水分限制技术用棉炭疽菌变种头孢霉型（Colletotrichum gossypii var. cephalosporioides）、截形炭疽菌（Colletotrichum truncatum）和菜豆炭疽菌（Colletotrichum lindemuthianum）接种棉花（G. hirsutum）、大豆（Glycine max L.）和菜豆（P. vulgaris L.）的种子，随后制备并通过扫描电子显微镜观察。采用标准扫描电子显微镜方法制备标本。对于经过吸水纸检验的种子，在玉米上可鉴定出镰孢菌属（Fusarium sp.），在棉花上可鉴定出棉炭疽菌变种头孢霉型和尖孢镰刀菌（Fusarium oxysporum），在菜豆上可鉴定出黄曲霉（Aspergillus flavus）、青霉属（Penicillium sp.）、根霉属（Rhizopus sp.）和毛霉属（Mucor sp.）。在接种种子的表面观察到了棉炭疽菌变种头孢霉型、截形炭疽菌和菜豆炭疽菌的结构。
