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Induction of embryogenic calluses from soybean (Glycine max) roots.

2004; Pontifical Catholic University of Chile; Volume: 31; Issue: 1 Linguagem: Inglês

10.7764/rcia.v31i1.1306

0718-3267

María del Pilar Bueno, Cecília Severin, Susana Gattuso, Graciela Giubileo,

Soybean genetics and cultivation

The use of calluses for the improvement of plants is an alternative procedure for the in vitro selection of characters such as disease resistance, tolerance to draught and salinity or other extreme conditions. The objective of this research is to develop a system for embryogenic callus production from soybean roots (Glycine max) and to identify its origin through histological techniques. Apexes (1 cm in length) of soybean roots were placed in a medium MS of Murashige and Skoog after seven days of emergence: MS1 with 135.7 μM 2,4 diclorophenoxiacetic acid (2,4-D) and MS2 with 13.3 μM benciladenine (BA) and 0.2 μM naftalen acetic acid (NAA), with 2 % of sucrose and 7 % of agar. The explants were kept dark for 15 days and were then subjected to a 16-h photoperiod. The calluses obtained were transferred to medium MS, for embryo production, supplemented with 1.66 μM indol butiric acid (IBA) and BA at different concentrations: 0.89; 1.78; 3.55 and 4.44 μM. The frequency of callus formation was 70 %. In the zone of the pericycle, histological studies showed the presence of cells with meristematic characteristics, like large central nucleus and dense cytoplasm before the seventh day from the in vitro inoculation, which indicates the initiation of callogenesis. The formation of embryogenic zones was observed in calluses alter 45 days of inoculation, while nodular formations with embryogenic characteristics were obtained after 40 days. To our knowledge, this is the first report about embryogenic callus production from soybean roots. El empleo de callos en programas de mejoramiento genetico es una via alternativa en la seleccion in vitro para caracteres como resistencia a patogenos, sequia, tolerancia a salinidad u otras condiciones extremas. El objetivo del presente trabajo fue desarrollar un sistema de produccion de callos embriogenicos a partir de raices de soja (Glycine max (L.) Merr) cv. Williams e identificar el origen de los mismos mediante tecnicas histologicas. Se sembraron apices de raices de soja de 7 dias (1 mm) en medio MS de Murashige y Skoog conteniendo 135,7 μM de acido 2,4 diclorofenoxiacetico (2,4-D) MS1 y 13,3 μM de benciladenina (BA) y 0,2 μM de acido naftalen acetico (ANA) MS2, en ambos casos con agar-agar 2% y 0,7%. Los explantos permanecieron 15 dias en oscuridad y luego con fotoperiodo de 16 h. Los callos obtenidos fueron transferidos a medio para la produccion de embriones: MS, suplementado con 1,66 μM de acido indol butirico (AIB) y distintas concentraciones de benciladenina (BA) 0,89; 1,78; 3,55 and 4,44 μM. La frecuencia de formacion de callos fue 70%. A traves de estudios histologicos se determino la presencia, en la zona del periciclo, de celulas con caracteristicas meristematicas, nucleo central grande y citoplasma denso antes de los 7 dias desde la siembra in vitro, lo que estaria indicando el momento de la callogenesis. La aparicion de zonas embriogenicas se visualizaron en los callos a partir de los 45 dias, las observaciones histologicas muestran a los 40 dias formaciones nodulosas con caracteristicas embriogenicas. Los resultados de este trabajo constituyen la primera mencion sobre la produccion de callos embriogenicos en raices de soja