Rice callus physiology - Identification of volatile emissions and their effects on culture growth

Rice (Oryza sativa L.) callus cultures modified the atmosphere of the headspace of the vessel used for culture maintenance by producing carbon dioxide, ethanol and ethylene, while utilizing oxygen. Small quantities of acetaldehyde and ethane were also measured in one cultivar. Under these conditions of culture maintenance, callus from some cultivars were much more difficult to keep alive than callus from others. The largest proportion of necrotic callus was produced from cultures growing under conditions of high ethylene production and low oxygen utilization. When callus was exposed to a controlled flowing gas mixture similar to that accumulated above necrotic callus, growth of 2 necrosis-susceptible cultivars was more strongly inhibited than growth of 2 necrosis-tolerant cultivars. The poor callus growth was associated with higher ethylene production and a lower rate of oxygen utilization