The effect of red onion bulb extract concentration as a growth regulator on the growth of Cattleya sp. orchid plantlets

Cattleya orchids are one of the most popular types of ornamental orchids due to their beautiful flowers and economic value. Tissue culture is an in vitro plant propagation technique that uses sterile artificial media to produce large quantities of uniform, disease-free seedlings. Red onion bulb extract contains plant growth hormones such as auxin, gibberellin, and vitamin Bl, which play a crucial role in stimulating plant growth, particularly root formation and tissue mass increase. This study aims to investigate the effect of red onion bulb extract concentration as a plant growth regulator (PGR) on the in vitro growth of Cattleya orchid plantlets. The method used was a Randomized Block Design with treatments of red onion extract at concentrations of control, 50, 75, 100 g/L, along with a control using MS % medium, each repeated six times. The parameters observed included increases in plantlets height and fresh weight during culture. The results showed that red onion extract significantly influenced plantlets growth, with the l00 g/L concentration yielding the highest increase in fresh weight (0.123 g). These findings indicate the potential of red onion extract as an effective plant growth regulator for Cattleya orchid tissue culture.