DARK RESPIRATION UNDER LOW-PRESSURE AND INCREASED ETHYLENE

Responses of plants seedlings to hypobaria (reduced pressure of air) e xposure (up to 8 kPa) and exogenously applied ethylene (10(-4), 10(-5) , 10(-6) kPa) was studied using a gasometric system based on CO2-laser photoacoustic spectrometer. The increase of CO2-evolution (in the dar k) by pea (Pisum sativum L.), wheat (Triticum aestivum L.), maize (Zea mays L.), barley (Hordeum vulgare L.) and pine seedlings (Pinus sylve stris L.) was revealed. Some differences in dynamics of CO2-evolution and signal magnitudes are probably stipulated by the objects specifici ty. The alcohol-dehydrogenase, isocitrate dehydrogenase, glucose-6-pho sphate dehydrogenase, phosphoenolpyruvate carboxylase activity and con tents of malate, pyruvate and lac tate were studied in pea leaves. It was shown that an anaerobic metabolism increases with time and also wh en the air pressure is decreased. An increase of CO2-evolution from et hylene-treated pea seedlings and alcohol-dehydrogenase activation were observed.