Metabolismo respiratório de raízes de espécies arbóreas tropicais submetidas à inundação

Aiming at elucidating certain aspects of the respiratory metabolism of roots of flood-tolerant tropical tree species (Lonchocarpus muehlbergianus, Sebastiania commersoniana and Sesbania virgata) as well as flood-intolerant species (Peltophorum dubium and Schinus terebinthifolius), plants were submitted to 2, 10 and 60 days of flooding. After these periods, the absorption of O2 and liberation of CO2 by the roots were determined. The respiratory metabolism of the roots of tolerant species presented a drop due to flooding. Only S. commersoniana presented a recovery in respiration after 60 days of flooding. The intolerant species S. terebinthifolius did not present alterations caused by flooding in its aerobic metabolism, whereas P. dubium, also intolerant, presented a drop in the absortion of O2 with two days of hypoxia, and recovery after 60 days. The liberation of CO2 in the tolerant species followed the same pattern of O2 absorption, with the exception of S. commersoniana, which presented a reduction in the liberation of CO2 after 60 days of flooding similar to what happened to P. dubium. In S. terebinthifolius there was no significant reduction with flooding. The difficulty in establishing a difference pattern in the respiratory metabolism of the species studied, concerning tolerance to flooding, emphasizes the complexity of tropical plant responses.