IN-VITRO MORPHOGENIC RESPONSE OF CELERY (Apium graveolens) EXPLANTS TO GROWTH REGULATORS

ABSTRACT

This study was conducted to investigate the callus formation of celery explants inoculated on Murashige and Skoog medium supplemented with growth regulator. The experiment was carried out in the Tissue Culture Laboratory, Nigerian Institute for Oil Palm Research (NIFOR), Edo State during the period of November 2023 to March 2024. The experiments were to determine suitable protocol of sterilants (HgCl₂ and NaClO) for in vitro culture of Apium graveolens explants and to determine the optimum growth regulator combination concentrations for growth response in Murashige and Skoog’s medium. The sterilants were applied serially starting with 0.2% HgCl₂ for 1min and 2mins followed by 2% NaClO for 2mins and 4mins. The levels of growth regulators evaluated in Murashige and Skoog’s medium were: celery inoculated on MS medium supplements without growth regulator, celery inoculated on MS medium with 0.5ppm of 2,4-D and 0.6ppm of Kinetin and celery inoculated on MS medium with 0.3ppm of Kinetin and 1.0ppm of NAA with ten replicates each; celery inoculated on MS medium with 1.0ppm of 2,4-D and 0.3ppm of Kinetin and celery inoculated on MS medium with 0.5ppm of NAA and 0.6ppm of BAP with four replicates each. Results showed explants treated with surface sterilants (HgCl₂ and NaClO) for a shorter duration (1 and 2mins) were all contaminated but with longer duration (2 and 4mins), not all cultures were contaminated. Out of 38 cultures, 6 cultures were healthy and 32 cultures were contaminated. Morphogenic response was observed and recorded for the treatment, 0.5ppm of NAA and 0.6ppm of BAP having a moderately higher response than the other treatments. It was also observed that treatment 0.5ppm of 2,4-D and 0.6ppm of Kinetin had no response to callus and suffered from microbial contamination.