Characterization of carbon metabolism in Opuntia ficus-indica Mill. exhibiting the idling mode of Crassulacean acid metabolism

Autor: Manfred Kluge, Orlando Queiroz, J. Brulfert, Danièle Guerrier
Rok vydání: 1987
Předmět:
Zdroj: Planta. 170:92-98
ISSN: 1432-2048
0032-0935
DOI: 10.1007/bf00392385
Popis: Upon transfer from well-watered conditions to total drought, long-day-grown cladodes of Opuntia ficus-indica Mill. shift from full Crassulacean acid metabolism (CAM) to CAM-idling. Experiments using (14)C-tracers were conducted in order to characterize the carbon-flow pattern in cladodes under both physiological situations. Tracer was applied by (14)CO2 fumigations and NaH(14)CO3 injections during the day-night cycle. The results showed that behind the closed stomata, mesophyll cells of CAM-idling plants retained their full capacity to metabolize CO2 in light and in darkness. Upon the induction of CAM-idling the level of the capacity of phosphoenolpyruvate carboxylase (EC 4.1.1.31) was maintained. By contrast, malate pools decreased, displaying finally only a small or no day-night oscillation. The capacity of NADP-malic enzyme (EC 1.1.1.40) decreased in parallel with the reduction in malate pools. Differences in the labelling patterns, as influenced by the mode of tracer application, are discussed.
Databáze: OpenAIRE
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