Comparative account of allelopathic potential of essential oil of Tagetes minuta L. and its major component cis-β-Ocimene

Abstract

The study aims to explore the chemical composition of volatile essential oil of Tagetes minuta and comparison of its allelopathic potential with cis-β-ocimene, a major component of oil. T. minuta L. is an exotic aromatic plant found growing in northern plains and western Himalayas in India. The water distilled essential oil from aerial parts of T. minuta (at flowering stage) was analyzed by GC-MS. The analysis revealed 27 compounds representing 95.73% of the oil. cis-b-Ocimene (44.56%), dihydrotagetone (28.52%), limonene (3.99%) and tagetone (7.42%) were its major compounds. A comparison of allelopathic effect of cis-b-ocimene was made with T. minuta oil using Cassia occidentalis L., a common wasteland weed, as test plant.  Laboratory study included growth studies in the form of germination, seedling length and dry weight of test plant under both treatments i.e. T. minuta oil and cis-b-ocimene. The inhibitory effect of ocimene was more significant as compared to oil. However, highest concentration (20µg/cc) of both treatments was found to be inhibitory with respect to all parameters.