Bean leaves lose the ability to photosynthesize after they have been stored in darkness at 0° (MARGULIES & JAGENDORF I960). The plastids from these aged leaves do not carry out Hill reactions with either NADP or 2,3’,6-trichlorophenolindophenol (TPIP) as acceptors but will reduce NADP when reduced 2,6-dichlorophenolindophenol is provided as an electron donor. The similarity of electron transport properties of plastids from aged leaves and of plastids treated with CMU suggested that both acted at the same site to block evolution of oxygen (MARGULIES & JAGENDORF I960). When aged leaves are placed in light at room temperature, both photosynthesis and Hill reaction activities are restored (MARGULIES & JAGENDORF i960). Fifty percent reactivation occurs within 0.25 hr. Half saturation for reactivation is about 50 footcandles with white fluorescent light. The present investigation was carried out to characterize further the electron transport properties of chloroplasts from aged bean leaves.
Keywords
- Aged Leaf
- Fresh Leaf
- Fluorescence Yield
- Manganese Content
- Sodium Ascorbate
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.