Estabelecimento e calogênese in vitro a partir de folhas e flores do bacurizeiro (Platonia insignis Mart)

Abstract

The bacurizeiro is a tree fruit tree native to the Brazilian Amazon, with high socioeconomic value is still in the process of domestication, is at risk of genetic erosion due to the pressure of land use by agriculture, and the lack of adequate propagation techniques. Thus, as a viable alternative for the species, micropropagation through somatic embryogenesis stands out, a technique that explores the totipotentiality and high plasticity that plant cells can provide, being an important tool for large-scale propagation of plants. An efficient propagation protocol will help to overcome the difficulties in producing seedlings for the formation of orchards of the species and will enable the selection of plants with the agronomic characteristics of interest. Therefore, the objective of this work is to determine whether leaf and floral explants are efficient for inducing bacuri callogenesis. For the induction of somatic embryogenesis, flowers and leaves from different matrices in regions of the state of Maranhão were used, composing four experiments. In all tests, floral and foliar explants underwent a disinfestation process according to the type of explant, before and during manipulation in laminar flow. Then the explants were carefully excised and inoculated in culture media with different combinations of growth regulators. Evaluations were performed regarding oxidation (%), callus induction (%), contamination (%) and survival (%) of explants. For the explants from flowers, the ovary segments were the only ones to present callus formation, therefore, indicated for the induction of bacuri somatic embryogenesis. The segments of ovaries in the culture media containing the three concentrations of Picloran plus the culture medium containing the lowest concentration of 2,4-D provided superior callus responses (%) when compared to the other culture media. The leaf explants did not provide the formation of calluses, and the contamination prevented the progress of the work, therefore, new experiments are needed that seek an efficient disinfestation protocol. Thus, the floral explants showed a high potential for the induction of callogenesis, and the ovary of the bacuri flower was the most responsive explant, in addition, culture medium with high concentrations of Picloram are efficient for the induction of calluses in the ovary of the flower from bacuri