Allelopathic effects of Xanthium strumarium L. on seed germination and seedling growth of crops

The allelopathic effects of aqueous leachates from roots, shoots, leaves and fruits of Xanthium strumarium at maturity and soil taken from underneath the X. strumarium was studied on germination and seedling growth of 6 crops (wheat, barley, maize, rice, cotton and sunflower). The dried X. strumarium plant parts were soaked individually in water (1:20, w/v) for 24 h. The leaf leachates caused maximum reduction in germination and germination index of test crops. Mean germination time was reduced in the order: maize > barley > rice> wheat > cotton > sunflower. The inhibitory effects on germination followed the order: maize > sunflower > barley > cotton > rice.

Leaf leachate caused maximum inhibition in seedling emergence of wheat, barley and rice, whereas, fruit leachates were most inhibitory to seedling emergence of maize, cotton and sunflower. The leaf leachates caused maximum reduction in seedling growth (shoot and root length) of wheat and barley, while fruit leachate were deleterious to maize, rice (expect dry weight) cotton and sunflower. Shoot leachates did not effect the shoot length, dry weight and seedling emergence of wheat, barley and maize. Soil beneath the X. strumarium plant also did not affect the seedling growth and seedling emergence of all crops.