Allelopathic potential of petal leachates of Cassia fistula L. against an invasive weed Alternanthera tenella L.
In Laboratory bioassays, the allelopathic potential of aqueous petal leachates of Cassia fistula L. were studied against A. tenella. Petal leachates of C. fistula at all concentrations inhibited the seed germination and seedling growth A. tenella in both petriplate and soil bioassays. Seed germination and seedling growth was inhibited due to the phenolic compounds (Gallic acid, Catechol and Tannic acid) except Gallic acid and Catechol in soil bioassay. Petal leachates caused adverse effects than standard phenolic compounds. The 20% petal leachate of C. fistula contained (42.67 mg/100 ml) total phenolics using the GC-MS, we detected and identified following phytochemicals : 2, 3-dihydro-3, 5-dihydroxy-6-methyl-4H-pyran-4-one; 2, 4, 5-Trimethyl-1, 3-dioxolane; Hexahydro-1, 2, 4, 5 tetramethyl-1, 2, 4, 5-tetrazine; Diphenyl ether; 1, 1-Dimethyl-4, 4-diethyl-. DELTA.-tetrazene; o-Hydroxybiphenyl in petal leachates of Cassia fistula. Spectrophotometric analysis quantified 35.78 mg/100 ml o-Hydroxybiphenyl. In petri plate and soil bioassays the o-Hydroxybiphenyl at 5, 10 and 15 ppm concentrations of C. fistula inhibited the seed germination and seedling growth of A. tenella.