EFFECT OF DIFFERENT ANTIMICROBIAL AGENTS ON THE FIBER DEVELOPMENT OF IN VITRO

The outer epidermal layer of the cotton ovule may differentiate in vitro to form a mass of white fluffy fibers in an appropriate liquid medium. The in vitro cultured fibers provide a model for studying not only the cellular physiology and development mechanism but also generate a key resource for promoter evaluation in developing fibers. However, the potential uses of in vitro cultured ovules are restricted due to the frequent problem of bacterial and fungal contamination. In this study, the effect of Ampicillin, Gentamicin and Sodium Azide on cotton fiber development was observed at various concentrations (100 µg/mL, 50 µg/mL and 0.5 µg/mL respectively) which were added in the media as contamination controlling agents. The in vitro grown ovules were evaluated at 5, 10, 15 and 20 DPA (days post anthesis) for fiber length, percent viable ovules producing fiber, ovules fresh weight and ovules dry weight. It was observed that ovules grown on the media containing either Gentamicin or Sodium Azide were unable to initiate normal number of fiber cells. Addition of Ampicillin to cultures enhanced the fiber length, ovule weight and percentage of viable ovules with fibers. The inhibitory effect of Gentamicin on fiber growth was reversible, when ovules were transferred to Gentamicin-free medium within 3 days after culture initiation. However, Sodium Azide resulted in irreversible fiber development inhibition. These results indicate that Ampicillin was not only efficient to control contamination but also enhanced the fiber and ovule development process