Abstract
Interesting observation of earlier investigation on regulation of leaf senescence in pigeon pea with serine prompted us to undertake studies on kinetin (Kn)-serine interaction in senescent leaf discs of Spinacia oleracea L., cv. S-23, over time, in the dark to determine their effectiveness individually, and in combination, on photosynthetic pigments, total soluble proteins, lipid peroxidation and activities of the senescence associated enzymes- protease, lipoxygenase (LOX), guaiacol peroxidase (POD) and superoxide dismutase (SOD). Serine and Kn each individually, and in combination, minimized loss in chlorophyll a and b in all days and carotenoids at day 6. Kinetin and serine retarded protein loss and also curtailed protease activity. POD activity increased in untreated leaf discs up to 6-day; SOD activity decreased in control as leaf discs senescence advanced. Senescence increased POD activity and promoted chlorophyll degradation. Serine along with Kn was able to minimize increases in POD and maintained slightly higher level of SOD activity in all days when compared with the control. Although, combined treatment of serine and Kn could lower malondialdehyde content slightly at day 2, LOX activity was reduced. Serine and Kn can scavenge ROS by regulating antioxidant enzymes during leaf senescence.
Key words: Spinacia oleracea, chlorophyll, lipid peroxidation, lipoxygenase, superoxide dismutase.
