Study of the lipoxygenase activity of Brassica in Elevated Level of CO₂ under Moisture Stress Condition

Elevated CO₂ delayed senescence by modifying certain physiological components resulting in increased seed filling period of the Brassica cultivars Pusa Gold and RH-30. The intensity of senescence was low under elevated CO₂ in both the cultivars exposed to irrigated and moisture stress conditions owing to the maintenance of chlorophyll pigments for a prolonged period. Lipoxygenase (LOX) activity was very low at elevated CO₂ under irrigation and also under moisture stress. The LOX activity in cv. RH-30 gradually increased up to flowering stage indicating slow rate chlorophyll degradation and sustained the chlorophylls content for longer period of time, whereas in cv. Pusa Gold the activities of the enzyme sharply increased up to post flowering. The study revealed that the CO₂ had modulating role in delaying senescence by adjusting some physiological processes and that CO₂ has a reverse effect on oxygenation of polyunsaturated fatty acids (PUFA) by LOX.