Adventitious regeneration from tulip, lily and apple explants at different oxygen levels

The effect of different O-2 levels on regeneration of adventitious organs was examined in various systems, viz., shoot regeneration from tulip bulb scale and stalk explants, bulblet regeneration from lily scale explants and root regeneration from apple stem slices. The explants were exposed to 2% O-2 (low O-2), 100% O-2 (high O-2) Or ambient air (20% O-2) Culture under continuous high O-2 conditions had a moderate adverse effect in all systems. Continuous culture at: a low level of O-2 had strong inhibitory effects in tulip and apple, but was promotive in lily. When low O-2 was applied only concurrent with the wound reaction, it had no or even an inhibitory effect (tulip stalks). High O-2, applied directly after cutting apple stem slices, had a slight inhibitory effect on adventitious root formation. Once the regenerated organs had been formed, low O-2 levels inhibited growth (in lily and tulip), and high O-2 levels were stimulating in tulip and inhibitory in lily on organ growth. Our results show that the allegedly toxic effect of O-2 is small Or does not occur.