LAUSR

This study investigated the effect of activated charcoal (AC) and 4amino-3,5,6-trichloro-2-pyridinecarboxylic acid (picloram) on callus induction and occurrence of mitotic aberrations in coffee cells. Explants from the first pair of expanded leaves (1 leaves) of Coffea arabica “Catimor CIFC 7963” were cultured on Murashige and Skoog (MS) medium supplemented with 1 μM 2,4-dichlorophenoxyacetic acid (2,4-D) + 5 μM 6-benzlyaminopurine (BA). The treatments included the following rates of AC application: 0.008%, 0.08%, 0.1%, and 1% (w/v). We also evaluated the effects of growth in MS medium supplemented with 1 μM 2,4-D + 5 μM BA + 10 mM picloram vs. 10 mM picloram as the sole plant growth regulator. The results showed that cells of the 1 leaves on MS medium + 1 μM 2,4-D + 5 μM BA + 0.008% AC were induced to callus (46.88% callus induction). In addition, callus induction (90.63% and 59.38%) was observed in the leaves cultured on MS medium + 1 μM 2,4-D + 5 μM BA + 10 mM picloram and on MS medium+10 mM picloram, respectively. However, the 4-month-old friable calli developed on MS medium containing picloram showed mitotic aberrations. Some of these included binucleated cells, a micronucleus in binucleated cells, and vagrant chromosome cells. These results highlight that both 0.008% AC and 10 mM picloram were able to induce the development of 4-month-old friable callus in a high proportion of C. arabica “Catimor CIFC 7963” cells, but while the former produced no mitotic aberrations, the latter induced mitotic aberrations in cells.