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Comparación de caracteres anatómicos y morfológicos de raíces de cambur 'Manzano' (Musa AAB) y 'Gran Enano' (Musa AAA)

Revista Científica UDO Agrícola, ISSN 1317-9152, Vol. 9, Nº. 2, 2009, pags. 376-382
Source: OAI

ABSTRACT Plants develop mechanic barriers among which are the amount and quality of surface serum, cell wall thickness, and width of protective tissue cells, which make difficult for pathogenic agents to penetrate. Anatomical and morphological characters of plant roots were compared in �Manzano� and �Gran Enano� banana plants, susceptible and resistant to Fusarium oxysporum f.sp. cubense (race 1), respectively, obtained from a commercial farm in Trujillo state, to analyze their relationship with their resistance or susceptibility to the Panamá disease. Three plants per cultivar were used. Roots were subdivided in three sections: basal, middle and apex and their thickness were measured with a vernier. Semi-permanent preparations with free hand transversal sections of the root were obtained, stained with safranin, mounted with water:glicerol (1:1) and observed with an Olympus Bx40 microscope at 500X. Statistical differences were found between cultivars with regard to root thickness, but not among root sections within each clone. �Manzano� banana roots were thicker (5.00 mm) than the �Grand Nain� ones (3.54 mm). Significant differences were not observed between clons but they were among sections. Cortex width in �Gran Enano� was less than in �Manzano� and no differences were observed among root sections. Diameter of vascular cylinder was similar in both clones and increased from the apex to the base. The total number of vessels was higher in �Manzano� roots; however, root sections did not show differences. Most of the vessels were not damaged, thus they would continue to be active conducting water and nutrients. There was not evidence of the association of the anatomical and morphological characteristics with resistance or susceptibility to pests. Las plantas desarrollan en sus órganos barreras mecánicas, entre estas el espesor, cantidad y calidad de las ceras superficiales, grosor de la pared celular y de las células que constituyen los tejidos protectores; que dificultan la entrada de los agentes patógenos. Se compararon caracteres anatómicos y morfológicos de raíces de plantas de cambur �Manzano� (Musa AAB) y �Gran Enano� (Musa AAA), cultivares susceptibles y resistentes, respectivamente, al ataque de Fusarium oxysporum f. sp. cubense (raza 1)�, obtenidas de una finca ubicada en el estado Trujillo, para analizar su relación con la resistencia o susceptibilidad al ataque del Mal de Panamá. Se utilizaron tres plantas de cada cultivar. Las raíces se subdividieron en tres tercios: apical, medio y basal y se midió su grosor en cada uno con la ayuda de un vernier digital. Se realizaron preparaciones semi-permanentes con secciones transversales a mano alzada, la tinción fue con safranina, el montaje con agua: glicerina (1:1) y la determinación de las variables con un microscopio óptico Olympus Bx40 a un aumento de 500X. Se presentaron diferencias significativas entre los cultivares, en cuanto al grosor de las raíces, pero no entre los tercios en cada clon. Las raíces de cambur �Manzano� resultaron ser más gruesas (5,00 mm) en comparación con las de �Gran Enano� (3,54 mm). No se observaron diferencias entre los clones en relación al espesor de las células rizodérmicas, pero si entre los tercios. El espesor de la corteza en el cultivar �Gran Enano� fue menor que en el �Manzano�, pero no varió significativamente entre las secciones. Los valores del diámetro del cilindro vascular fueron similares y aumentaron desde el tercio apical al basal, para ambos cultivares. El número total de vasos conductores fue mayor en las raíces de �Manzano�, sin embargo, las secciones no mostraron diferencias. La mayoría de los vasos se observaron sanos por lo que la función de estos en las raíces se vería muy poco afectada y los mismos seguirían siendo activos en la conducción de agua y nutrientes. No se observó evidencia de características anatómicas asociadas con la resistencia o susceptibilidad a enfermedades y plagas.

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