The Ability of Glutathione and Ascorbic Acid to Increasing Growth Vigor and Enhancing the Allelopathic Capability of Marjoram (Origanum majorana L.) Against Growth Retardatory Weeds
A pot trial was conducted to study the potential effect of Glutathione (GSH) and Ascorbic acid (ASA) either applied alone or in combination at different rates of concentration (50-250 and 25-100 mg L-1, respectively) on controlling weeds and yield productivity of marjoram (Origanum majorana L.). The two compounds and their combinations were applied as a post-emergence application after 30 days from sowing. Applying the two compounds alone at different concentrations significantly inhibited the broad and narrow-leaved weeds by up to 56 and 60%, respectively. The combined effect of the two compounds was more efficient in this regard (up to 100% weed reduction) than the individual application. Marjoram growth and development was seriously affected (up to 63% growth induction) at all levels of studied criteria. The effect was more pronounced on increasing the elementary components of total sugar, total nitrogen and oil yield (up to 91%); irrespective of the rate and sort of application. The in vitro study of the allelopathic influence of marjoram oil extracts against seed germination (%) and seedling root and shoot length of certain broad and narrow-leaved weeds (e.g., Amaranthus cruentus and Echinochloa crus-galli) revealed of more superiority of the treated plants rather than the untreated one. GLC analysis also showed a significant increasing in the terpene (oxygen-containing monoterpenes in particular) and phenolic substances in the treated plants. It has been suggested that applying GSH or ASA either alone or in combination might have a direct and/or indirect impact on increasing the allelopathic capacity of marjoram plants by increasing their content of the terpene and phenolic substances, which could be the key factor of the allelopathic influence of marjoram plants in their vicinity.
Cited References Fulltext