ALLELOPATHIC EFFECT OF AQUEOUS EXTRACTS OF WEEDS ON MEDICINAL PLANTS

the allelopathic influence of various weed extracts on different medicinal plants.

Abstract

A pot experiment was carried out in 2020 to assess the allelopathic influence of various weed extracts on different medicinal plants. The experiment was laid out in a two factorial CR design replicated three times. Factor A comprised of medicinal plants viz. Linum usitatissimum, Nigella sativa, Foeniculum vulgare, Plantago ovata, and Matricaria chamomilla; while factor B included aqueous extracts of Silybum marianum, Parthenium hysterophorus, and Broussonetia papyrifera, along with a herbicide (atrazine) and a control. Data was recorded on germination percentage, root and shoot lengths (cm), fresh and dry biomasses (g), antioxidant activity, total phenolic content, total flavonoid content, chlorophyll content, and antibacterial activity. The results showed that extracts of weeds had stimulatory effects on the growth of medicinal plant species, a phenomenon called hormesis. The aqueous extracts of the tested weeds enhanced the seed germination and significantly affected all the parameters tested in the experiment. The highest shoot length was of L. usitatissimum treated with S. marianum extract and the lowest was recorded also in L. usitatissimum with atrazine application. Similarly, the root length of L. usitatissimum was highest under P. hysterophorus extract application and the lowest was again in L. usitatissimum under B. papyrifera extract. The highest fresh biomass was of M. chamomilla and lowest in P. ovata under P. hysterophorus. Similarly, dry biomass was found highest in M. chamomilla in control, while lowest was of L. usitatissimum under B. papyrifera treatment. The antioxidant content was maximum in F. vulgare under B. papyrifera and minimum in P. ovata under Parthenium. The total flavonoid content was on top in F. vulgare under B. papyrifera and the least flavonoid content was in L. usitatissimum under Parthenium. The total phenolic content was greatest in M. chamomilla under Parthenium and the lowest in F. vulgare treated with atrazine. Moreover, the greatest Escherichia coli content was found in F. vulgare under B. papyrifera the smallest in M. chamomilla under Silybum extract. The highest content of Staphylo coccus bacteria was in N. sativa under atrazine and lowest in F. vulgare under S. marianum. The Agro-bacterium activity was highest in N. sativa under control and lowest in M. chamomilla under atrazine. The Citro bacter was highest in F. vulgare treated with B. papyrifera while lowest in P. ovata under P. hysterophorus. The chlorophyll content was highest in L. usitatissimum and lowest in P. ovata under S. marianum.