Influence of different ethylene inhibitors on somatic embryogenesis and secondary embryogenesis from Coffea canephora P ex Fr.

The effect of cobalt chloride, salicylic acid, and
silver nitrate for embryogenesis was studied in in vitro
cultures of Coffea canephora. Murashige and Skoog (in
Physiol. Plant. 15:473–497, 1962) medium containing 20
and 40 μM either of cobalt chloride, silver nitrate, or
salicylic acid supplemented with 1.1 μM N6 benzyladenine
and 2.85 μM indole-3-acetic acid was used for the study. At
20 and 40 μM silver nitrate treatment, 35–48% explants
responded for embryogenesis, and 38±7 and 153±27
embryos were produced from each callus mass, respectively,
whereas only 5% control explants responded on medium
devoid of silver nitrate, cobalt chloride, or salicylic acid.
Secondary embryogenesis was observed in 70–90% of the
explants, and around 100–150 embryos were produced
from each explant cultured on a medium containing silver
nitrate, and only a 3% response was noticed in control
embryo explants. Yellow friable embryogenic calluses were
obtained from the cut edges of most of the tissues grown in
a medium supplemented with cobalt chloride. The results
clearly demonstrated that, among the tested ethylene
inhibitors, silver nitrate is very effective in reprogramming
the cellular machinery toward embryogenesis.