Inducción in vitro a la poliploidía en Caucaea pichinchae (Orchidaceae), mediante el uso de colchicina

Abstract

Polyploidy induction is one of the most used procedures in the area of cytogenetics, molecular and cellular biology for the improvement of plants under in vitro conditions; however, despite the multiple benefits that this technique provides, no species of the Caucaea genus has actually been exposed to Colchicine or some other type of chemical to genetically enhance them. For this reason, the objective of this research was to develop protocols for the in vitro induction of polyploidy in individuals of the species Caucaea pichinchae through the use of Colchicine. The research was carried out in the Plant Biotechnology Laboratory of the Salesiana Polytechnic University. As plant material, protocorms in the process of dedifferentiation of the species Caucaea pichinchae were used, which were exposed to three concentrations of Colchicine (0.05%, 0.10% and 0.2%) and four exposure times (24, 48, 72 and 96 hours). A completely randomized factorial design with a 3x4 factorial arrangement was used. The data obtained were analyzed using an ANOVA model together with a Turkey test for the comparison of means, where it was determined that the viability of protocorms was highly affected by both exposure time and concentration. Likewise, a Chi square test was used to demonstrate the development of polyploidy in the species. The results indicate that control protocorms maintained only with sterile distilled water did not present cytogenetic changes (2x=10), while those that were exposed with 0.05%, 0.10% and 0.20% Colchicine for 24 hours and with 0.10% exposure for 48 hours, they showed polyploid cells (2x=20), however, when the exposure time increased to 72 and 96 hours with concentrations greater than 0.1%, the protocorms in the process of dedifferentiation presented proportional or complete cell death in its tissue. Finally, for visualization and chromosome counting in Caucaea pichinchae, it began with a phase of pretreatment, fixation, hydrolysis and ending with a double staining, managing to observe the increase in chromosomes in the species.