Modulation of nitrogen metabolising enzymes and the photosynthetic pigments in wheat upon exogenous application of marigold leachates

Laboratory and pot experiments were conducted to evaluate the influence of leachates of fresh/dry parts of marigold on photosynthetic pigments and nitrogen metabolism of wheat. Considerable decline in chlorophylls and carotenoids and the activities of enzymes of nitrogen metabolism (nitrate reductase, alanine and aspartate aminotransferases, glutamate dehydrogenase and glutamate synthase) was noticed in plants treated with higher concentration of fresh (30% w/v) or dry (10% w/v) leaf and flower leachates of marigold. However, treatment of lower concentrations i.e., 5% (w/v) of leachates of fresh parts and 1% (w/v) leachates of dry parts imparted stimulatory effects. Sodium and potassium contents in different parts of wheat plants showed a significant increase with the increase in the concentration of dry leachates both at pre-flowering and flowering stages. On the other hand, nitrogen and calcium content exhibited a decline with the increase in concentration of leachates. The study indicates that identification of allelochemicals in these leachates may probably help evaluation of marigold as a natural herbicide for sustainable agriculture paving way for further study.