Oxidation during the induction of somatic embryogenesis with immature male flowers of Grand Nain (Musa AAA)

The bananas and plantains (Musa spp.) are economically important crops in the world. Their classical improvement has very limitations which could be overcome with transgenic plants. Plant trangenesis require an efficient method for multiplication and regeneration like somatic embryogenesis. For somatic embryogenesis induction the more used explant are immature male flowers; however the application of this method has practice difficulties for flower extractions. More recently was reported a more simple methodology applied in the cultivar Dwarf Brazilian (Musa AAB) to process the male immature flowers but is not described the oxidation problems that could be occurred for the application of this methodology. The objective of this research was to evaluate the phenolic oxidation during the somatic embryogenesis induction in explants with immature male flowers of Grand Nain using both methods for the explants extraction. Male buds were reduced and sterilized with isopropyl alcohol, washed with sterile water and reduced again. From each sterilized male bud were extracted immature male flowers with two methods: the conventional method (isolating floral hands) and the new method (separating the acorn). All the explants were cultured during 7 to 9 month in semisolid media, in dark at 27 +/- 4 degrees C. A low percentage of explants were obtained with intense oxidation in the flowers, so much when using the conventional method (7.35%) as the novel methodology (0.25%). In general, the oxidation didn't affect the establishment of the explants and the extraction of the same ones was simpler when applying the new method.