Fig. 8

Monitoring of NDH activity by chlorophyll fluorescence. Mature leaves of three Paphiopedilum species were exposed to actinic light (AL, 200 μmol photons m⁻² s⁻¹) after the measuring light was turned on (Fo, the minimum level of chlorophyll fluorescence). The AL was turned off and the subsequent change in chlorophyll fluorescence was monitored as an indicator of NDH activity. The mature leaf was dark-adapted at 25 °C for 30 min, and the chlorophyll fluorescence was measured at 25 °C