Photoperiod and silver ions modulate in vitro flowering in Oldenlandia herbacea (L.) Roxb.

Oldenlandia herbacea (L.) Roxb. is an important medicinal plant of Indian, Malayan, and Chinese traditional systems of medicines. In vitro flowering system serves as a model system to study flowering physiology, and role of combination of photoperiodic conditions and ethylene inhibitors. Ethylene is responsible for delayed flowering response in plants; hence, it is interesting to explore the role of ethylene inhibitors and photoperiod on flowering mechanism. The present study, for the first time, reports the influence of silver thiosulfate (STS), silver nitrate, and photoperiod (PP) to induce high-frequency in vitro flowering in O. herbacea. The flowers were induced from the in vitro shoots (2.0 floral buds per shoot) on MS medium containing 4 μM 6-benzylaminopurine + 2 μM indole-3-acetic acid + 5 μM STS at 14-h PP. This study could be the foundation to understand the role of PP and silver ions on flowering physiology at molecular level.