Organogênese indireta e criopreservação de gemas laterais e de unidades encapsuláveis de mangabeira

Abstract

Mangabeira is a species native to Brazil and has great economic potential, but the percentage of seed germination is low, and presents recalcitrance, which reduces the productivity of the species, influencing the maintenance and upkeep of the plant material. Aimed to: obtain seedlings via indirect organogenesis, as well as lateral buds using cryopreservation techniques droplet vitrification and encapsulation-vitrification. For indirect organogenesis, nodal segments were inoculated in culture medium WPM supplemented with different growth regulators: 2,4-D (0.0, 2.46, 7.38, 12.3 17.22 µM), BAP (0.0, 4.92, 9.84, 14.76 and 19.68 µM) and TDZ (0.0, 4.92, 9.84, 14.76 and 19.68 µM). Regeneration of shoots was performed in culture medium WPM plus kinetin in combination with 2,4-D (0.0 + 0.0, 5.0 + 0.0 and 5.0 + 7.38 µM). For rooting shoots were subjected to treatments with different auxins AIB, ANA and AIA. For cryopreservation, lateral buds were inoculated in WPM culture medium with different concentrations of BAP (0.0, 0.2, 0.8 and 1.6 µM), GA3 (0.0, 0.2, 0.8 and 1.6 µM) and 0.25 µM of BAP in combination with GA3 (0.0, 0.2, 0.8 and 1.6 µM). Buds were pre-grown in culture medium WPM with different concentrations of proline (0.0, 0.1, 0.2 and 0.3 M) for different times (24 and 48 hours) in the absence of light. After the pre-cultivation the shoots were immersed in PVS2 at 0 ° C for different times (0, 15, 30, 60 and 120 minutes) and subsequently subjected to droplet vitrification technique. The encapsulation of lateral buds were obtained in the alginate matrix, the presence or absence of BAP (0.0 or 0.2 µM). The capsules were pre-cultured in liquid culture medium WPM, together with different concentrations of sucrose (0.3, 0.75 and 1 M) for different times (24 and 48 hours). The capsules were subjected to dehydration silica gel or laminar flow with 0, 1, 2 and 3 hours before immersion in PVS2 at 0 ° C for different periods. The highest percentage of number of shoots (72.86%) was obtained at a concentration of 7.38 µM of 2,4-D. Increased shoot regeneration with the combination of kinetin + 5 µM 7.38 µM of 2,4-D was obtained. Shoots showed higher rooting percentage (80%) on treatment with ANA and AIB. The preculture in 0.1 M proline for 24 hours promoted an increase in survival percentage (83.33%). The use of PVS2 for 15 minutes showed higher survival rates (78%). Lateral buds encapsulated in the presence of 0.2 µM of BAP (86%) and pre-cultured in 0.75M sucrose for 24 hours, dehydration associated with the flow chamber for 1 hour, had higher regenerating rate. Cryopreservation of lateral buds encapsulated was successfully obtained using PVS2 for 15 minutes.