TheCaesalpinia peltophoroides cell cycle under different aeration conditions

Summary Cell cycle parameters were studied inCaesalpinia peltophoroides meristems proliferating under different oxygen tensions. This species has been selected for mixed planting in degraded areas in Brazil, some of which are occasionally flooded. As the species’ adaptation to oxygen deprivation during flooding is not fully understood, the objective of this study was to characterize the meristematic activity of root cells under various oxygen regimes. Synchronous binucleate cells, induced by a pulse of caffeine, showed a cell-cycle time constant under both control (5.6 mg of O₂ per l) and oxygenated conditions (7.9 and 3.2 mg of O₂ per l). The whole cell cycle lasted 10 h, although the relative duration of metaphase and anaphase/early telophase increased in more hypoxic conditions. The species appeared to utilise oxygen diffusing from the shoot to the root system to maintain cell division and root growth.