In India, mungbean is the 3rd major pulse crop cultivated for best source of proteins, carbohydrates and minerals. Seed germination and germination physiology play an important role in crop production. Ornamental plant Delonix regia is planted as shade tree in farm competes with neighboring plant species. Phytotoxins released by dry, dropped leaves of Delonix may have adverse effects on neighboring crop plants. Hence a study was carried out to evaluate the effect of aqueous leachates of leaves of D. regia on germination and some metabolic facets of seedlings of mungbean. In petriplate bioassay root length (74.62%, 17.20%, and 47.31%) and shoot length (76.43%, 16.98% and 46.70%) were reduced due to 20%, 0.2%, and 0.1% respectively. In soil bioassay, decrease in root length (16.09%, 13.73%, 1.02%) was observed. In petriplate bioassay a decrease in starch content (14.55%, 10.97%, 36.42%), reducing sugar (60.94%, 67.45%, 17.45%), total sugar (43.50%, 57.62%, 18.25%) and increase in protein content (54.26%, 13.42%, 42.61%) was observed due to treatment of leaf leachates. In soil bioassay, there was increase in starch (42.24%, 1071.12%, 859.66 %) and total sugar content (20.06%, 63.78%, 23.81%) and decrease in reducing sugar content (32.93%, 3.44%, 15.17%) and soluble protein content (3.64%, 0.298%) in seedlings of mung bean. Leaf leachate showed considerable amount of polyphenols and number of phytochemicals. Inhibition of seed germination, seedling growth and alteration in metabolism of mungbean seedlings may be due to the synergistic effect of appreciable amount of polyphenols and phytochemicals present in the leaf leachates.
