Cultivo in vitro de Cochlospermum regium (Schrank) Pilger

Abstract

Cochlospermum regium is a native species to the Cerrado that has economic importance because of its medicinal potential. The destruction of the biome and the unrestricted use of C. regium roots by local human populations, which are aimed at producing phytotherapics, has aggravated its risk to extinction. However, studies concerning the micropropagation of the species are still scarce, especially when considering the development of protocols that seek to define the best conditions for their in vitro culture, such as the chemical sterilization of the culture medium and indirect organogenesis. This study aimed at: (i) Developing a protocol for multiplication of axillary buds of Cochlospermum regium through chemical sterilization of the culture medium, being the experiment conducted in a completely randomized design with factorial arrangement (4x5) with plots split through time. In this experiment, we used four preparations of the culture medium (M1 – autoclaved, M2 – 0.001%, M3 – 0.003%and M4 – 0.005% of active chlorine added to the culture medium) and five subcultures;(ii) Developing an indirect organogenesis protocol aimed at callus formation and regeneration of shoots, where the treatments were the combination of the type of explant (cotyledon, hypocotyl and root) and the type of plant growth regulator (2,4-D, TDZ and NAA). The experiments were conducted in a completely randomized design in factorial scheme (3x3). As regards the multiplication protocol of axillary buds concerning the chemical sterilization of the culture medium, the conventional preparation of the culture medium (autoclaved) showed the best results in comparison to the culture medium supplemented with active chlorine. However, it was possible to recommend the use of 0.005% of active chlorine for the chemical sterilization of the culture medium (without autoclaving), showing satisfactory control of contaminants (such as bacteria and fungi)/It also exhibited the best shoot proliferation results. As what concerns indirect organogenesis, we found that TDZ (thidiazuron) was the growth regulator that most favored callus induction regardless of the explant used. Mean while, when associated with the hypocotyl explant type, it resulted in the best responses and the regeneration of adventitious shoots.