Effect of Culture Medium in Callogenesis from Adult Walnut Leaves (Juglans regia L.)

To define preliminary aspects of walnut (Juglans regia L.) callogenesis in indirect propagation systems, this work analyzed callogenic induction in adult leaves of walnut in broadleaf trees (BTM), Murashige and Skoog (MS) Driver Kuniyuki Walnut (DKW) and Woody Plant (WPM) media. Leaf segments of 1 cm², previously sterilized, were placed in each culture medium, supplemented with 21.4 µM naphtalene acetic acid (NAA) and 8.8 µM 6-benzylaminopurine (BAP). A completely random design was used; the experimental unit was a Petri dish with six callus explants. Each treatment was composed of seven Petri dishes. Callogenesis (%), nodular calli (%) and histology of calli explants were evaluated at 4 weeks by staining 10 µm slices with safranine-fastgreen. There were no significant differences (α = 0.05) in callogenesis among evaluated media; but nodular calli percentages were significantly higher in BTM (75%) and WPM (63%). Only in calli obtained in the BTM medium did the histology show the presence of meristematic zones, but without external expression. These results indicate that the medium influences the morphogenic characteristics of resultant callus. Calli produced in BTM presented better morphogenic potential, with meristems at primary stages of organization. Con el objeto de definir aspectos preliminares de la callogénesis de nogal(Juglans regia L.), para establecer, sistemas de propagación vegetativa vía indirecta, este trabajo analizó la inducción callogénica en hojas adultas de nogal, utilizando los medios de cultivo broadleaves tree (BTM), Murashige y Skoog (MS), Driver Kuniyuki Walnut (DKW) y Woody Plant (WPM). Se utilizaron segmentos foliares de 1 cm² previamente esterilizados fueron dispuestos en cada medio de cultivo suplementado con 21,4 µM de ácido naftalén acético (ANA) y 8,8 µM de 6-bencilaminopurina (BAP). Se utilizó un diseño completamente aleatorio, la unidad experimental correspondió a una placa Petri con seis segmentos foliares. Cada tratamiento estuvo compuesto por siete repeticiones. A las 4 semanas de cultivo se evaluó la callogénesis (%), callos nodulares (%), e histología de macizos callosos, para los que se obtuvieron cortes de 10 µm a los cuales se realizó tinción con safranina-fastgreen. No se registraron diferencias significativas en la inducción de callogénesis entre los medios evaluados (α = 0,05); pero el porcentaje de callos nodulares fue significativamente mayor en los medios BTM (75%) y WPM (63%). Sólo en el medio BTM,